Introductory Chapter: Indoor Environmental Quality

*Muhammad Abdul Mujeebu*

### **1. Overview**

The term "indoor environmental quality" (IEQ ) represents a domain that encompasses diverse sub-domains that affect the human life inside a building. These include indoor air quality (IAQ ), lighting, thermal comfort, acoustics, drinking water, ergonomics, electromagnetic radiation, and many related factors [1], as depicted in **Figure 1**. Enhanced environmental quality can improve the quality of life of the occupants, increase the resale value of the building, and minimize the penalties on building owners.

IEQ in offices and other workplaces has a crucial role on the return on investment of businesses. A workplace with high IEQ obviously improves the workers' health and mood, thereby increasing their productivity. Therefore, the additional cost of maintaining high IEQ levels in workplaces will be paid back in a reasonable period and generates additional monetary returns thereafter. It should be noted that buildings being rated as "sustainable and green" do not truly guaranty their compliance with the desired IEQ level [2–5]. Therefore, IEQ should be given specific focus while designing new buildings as well as in building retrofit plans.

**Figure 1.** *IEQ components.*

### **2. Indoor air quality**

Indoor air quality (IAQ ), which depends on airborne contaminants inside a building (or in a broader sense, any other enclosure such as a vehicle or an animal house), is one of the crucial factors that determine the quality of the indoor environment. Providing adequate air quality for the occupants is one of the most important functionalities of a building. Lung cancer (due to radon), Legionnaires' disease, carbon monoxide poisoning, allergy, and asthma are among the serious health implications of poor IAQ [6]. The "sick building syndrome" resulting from inadequate levels of IAQ significantly affects the health and productivity of office employees [7]. Though tremendous efforts are in progress to realize energyefficient, green, and sustainable buildings, maintaining a safe level of IAQ in these buildings is an ongoing challenge. This is due to the fact that many energy-efficient measures in a building (such as reduced outdoor air ventilation rate, increased thermal insulation, and efficient cooling equipment) can have a detrimental impact on IAQ. Thus, alongside energy efficiency and sustainability, there has been a growing concern over air pollution inside buildings. Therefore, attempts to ensure energy efficiency and sustainability in buildings should simultaneously ensure enhanced health, comfort, and productivity of the occupants [6].

There are two major approaches to tackle IAQ issues in buildings: one is to increase the ventilation rate of outdoor air into the building, and the other is to minimize or control the sources of air pollution within and outside the building. Having said that, the first strategy would work only when the outdoor air is clean enough to improve IAQ [7]. The various sources that affect IAQ are, but not limited to, volatile organic compounds, biological pollutants, oxides of carbon and nitrogen, particulate matter, tobacco smoke, radon, mold, formaldehyde, pesticides, and combustion products. Heseltine and Rosen [8] outlined health issues associated with building moisture and biological agents, and the most important health problems identified are respiratory symptoms, allergies, asthma, and perturbation of the immunological system. A recent review [9] has revealed that carpets play a crucial role in IAQ, as they act as a sink for indoor air pollutants such as particles, allergens, and other biological pollutants.

### **3. Thermal comfort**

The term "thermal comfort" refers to a condition that is governed by many environmental and human factors; in other words, physiological, physical, and sociopsychological factors. The environmental factors include air temperature, air velocity, humidity, radiant temperature, and relative humidity, while the major human factors are clothing and metabolic heat. The various other factors include physical health, mental condition, availability of food and drink, and acclimatization. This condition is mostly subjective, which cannot be directly quantified. It has been established that the thermal comfort level is acceptable if at least 80% of the occupants feel comfortable with it. Djongyang et al. [10] and Taleghani et al. [11] provided detailed insights into the thermal comfort in buildings.

#### **4. Lighting comfort**

Visible light falls in a narrow range in the electromagnetic spectrum, between ultraviolet and infrared wavelength ranges. Light has both particle and wave

**3**

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

objects and affects the retina.

daylighting.

**5. Acoustic comfort**

cally 20–20,000 Hz.

these characteristics.

properties; when treated as a wave, light has a frequency that depends on the color of the struck surface. For instance, white surface reflects back most of the incident light, while a black surface absorbs most of it. The main aspects of lighting comfort are light level (intensity or brightness), contrast, and glare. The light intensity requirement depends on the type of activity in the building; for instance, operating rooms need a brighter level than living rooms. The term "contrast" refers to the ease of understanding or legibility; higher contrast gives higher clarity (e.g., black text on white paper provides the highest contrast). Glare is always undesirable as it causes a high level of discomfort in viewing the

The visual comfort level is evaluated by means of some established glare metrics or indices; for example, glare probability (DGP) and daylight glare index (DGI) are used for assessing discomfort due to daylighting, while unified glare index (UGI), visual comfort probability (VCP), and CIE glare index (CGI) are employed for measuring the discomfort level of artificial lighting [12–15]. Several other indices are also available, as summarized by Carlucci et al. [12]. Galatioto and Beccali [16] reviewed the various aspects and concerns associated with the assessment of indoor

Building acoustics deals with controlling the quality of sound inside a building. It has two parts, namely, room acoustics and building acoustics, which deal with the sound propagation within a room and between rooms (through walls, doors, and floors), respectively. While the room acoustics focuses mainly on the sound quality (e.g., easy communication and high level of intelligibility in office spaces), the building acoustics is concerned with the "unsolicited" sound (e.g., the noise in a room should not be a nuisance to other rooms). The acoustic comfort in a building has a crucial impact on the health, well-being, communication, and productivity of the occupants. The acoustic comfort can be affected by factors such as the geometry and volume of a space, generation of sound within or outside the space, airborne noise transmission, impact noise, and the acoustic characteristics (absorption, transmission, and reflection of sound) of the interior surfaces. The measuring unit of sound intensity is decibels (dB), and of sound pitch is hertz (Hz). The comfortable range of sound for humans is typi-

The common parameters used for evaluating the acoustic performance of a building are reverberation time (RT), sound pressure level (SPL), early decay time (EDT), clarity (C50 for speech and C80 for music), sound definition or speech intelligibility (D or D50), and speech transmission index (STI). RT is defined as the time for the sound level to decay by 60 dB after a sound source has been switched off. EDT is similar to RT, but it is the initial rate of sound decay in a room, measured as the slope of a line 0–10 dB decay below the maximum sound level. D50 is defined as the ratio of the early received sound energy (0–50 ms after direct sound arrival) to the total received energy. Clarity is defined as the ratio of the energy in the early sound (received in the first 80 ms) to that in the reverberant sound. STI is a measure of speech transmission quality, which indicates the degree to which a transmission channel degrades speech intelligibility. STI ranges from 0 to 1; a speech transferred through a channel with STI of 1 is perfectly intelligible, but the intelligibility reduces as the STI approaches zero. International standards and guidelines (e.g., ISO 18233) are available for the measurement of

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

*Indoor Environmental Quality*

**2. Indoor air quality**

Indoor air quality (IAQ ), which depends on airborne contaminants inside a building (or in a broader sense, any other enclosure such as a vehicle or an animal house), is one of the crucial factors that determine the quality of the indoor environment. Providing adequate air quality for the occupants is one of the most important functionalities of a building. Lung cancer (due to radon), Legionnaires' disease, carbon monoxide poisoning, allergy, and asthma are among the serious health implications of poor IAQ [6]. The "sick building syndrome" resulting from inadequate levels of IAQ significantly affects the health and productivity of office employees [7]. Though tremendous efforts are in progress to realize energyefficient, green, and sustainable buildings, maintaining a safe level of IAQ in these buildings is an ongoing challenge. This is due to the fact that many energy-efficient measures in a building (such as reduced outdoor air ventilation rate, increased thermal insulation, and efficient cooling equipment) can have a detrimental impact on IAQ. Thus, alongside energy efficiency and sustainability, there has been a growing concern over air pollution inside buildings. Therefore, attempts to ensure energy efficiency and sustainability in buildings should simultaneously ensure enhanced

There are two major approaches to tackle IAQ issues in buildings: one is to increase the ventilation rate of outdoor air into the building, and the other is to minimize or control the sources of air pollution within and outside the building. Having said that, the first strategy would work only when the outdoor air is clean enough to improve IAQ [7]. The various sources that affect IAQ are, but not limited to, volatile organic compounds, biological pollutants, oxides of carbon and nitrogen, particulate matter, tobacco smoke, radon, mold, formaldehyde, pesticides, and combustion products. Heseltine and Rosen [8] outlined health issues associated with building moisture and biological agents, and the most important health problems identified are respiratory symptoms, allergies, asthma, and perturbation of the immunological system. A recent review [9] has revealed that carpets play a crucial role in IAQ, as they act as a sink for indoor air pollutants such as particles,

The term "thermal comfort" refers to a condition that is governed by many environmental and human factors; in other words, physiological, physical, and sociopsychological factors. The environmental factors include air temperature, air velocity, humidity, radiant temperature, and relative humidity, while the major human factors are clothing and metabolic heat. The various other factors include physical health, mental condition, availability of food and drink, and acclimatization. This condition is mostly subjective, which cannot be directly quantified. It has been established that the thermal comfort level is acceptable if at least 80% of the occupants feel comfortable with it. Djongyang et al. [10] and Taleghani et al. [11] provided detailed insights into the thermal comfort in

Visible light falls in a narrow range in the electromagnetic spectrum, between

ultraviolet and infrared wavelength ranges. Light has both particle and wave

health, comfort, and productivity of the occupants [6].

allergens, and other biological pollutants.

**3. Thermal comfort**

**2**

buildings.

**4. Lighting comfort**

properties; when treated as a wave, light has a frequency that depends on the color of the struck surface. For instance, white surface reflects back most of the incident light, while a black surface absorbs most of it. The main aspects of lighting comfort are light level (intensity or brightness), contrast, and glare. The light intensity requirement depends on the type of activity in the building; for instance, operating rooms need a brighter level than living rooms. The term "contrast" refers to the ease of understanding or legibility; higher contrast gives higher clarity (e.g., black text on white paper provides the highest contrast). Glare is always undesirable as it causes a high level of discomfort in viewing the objects and affects the retina.

The visual comfort level is evaluated by means of some established glare metrics or indices; for example, glare probability (DGP) and daylight glare index (DGI) are used for assessing discomfort due to daylighting, while unified glare index (UGI), visual comfort probability (VCP), and CIE glare index (CGI) are employed for measuring the discomfort level of artificial lighting [12–15]. Several other indices are also available, as summarized by Carlucci et al. [12]. Galatioto and Beccali [16] reviewed the various aspects and concerns associated with the assessment of indoor daylighting.

### **5. Acoustic comfort**

Building acoustics deals with controlling the quality of sound inside a building. It has two parts, namely, room acoustics and building acoustics, which deal with the sound propagation within a room and between rooms (through walls, doors, and floors), respectively. While the room acoustics focuses mainly on the sound quality (e.g., easy communication and high level of intelligibility in office spaces), the building acoustics is concerned with the "unsolicited" sound (e.g., the noise in a room should not be a nuisance to other rooms). The acoustic comfort in a building has a crucial impact on the health, well-being, communication, and productivity of the occupants. The acoustic comfort can be affected by factors such as the geometry and volume of a space, generation of sound within or outside the space, airborne noise transmission, impact noise, and the acoustic characteristics (absorption, transmission, and reflection of sound) of the interior surfaces. The measuring unit of sound intensity is decibels (dB), and of sound pitch is hertz (Hz). The comfortable range of sound for humans is typically 20–20,000 Hz.

The common parameters used for evaluating the acoustic performance of a building are reverberation time (RT), sound pressure level (SPL), early decay time (EDT), clarity (C50 for speech and C80 for music), sound definition or speech intelligibility (D or D50), and speech transmission index (STI). RT is defined as the time for the sound level to decay by 60 dB after a sound source has been switched off. EDT is similar to RT, but it is the initial rate of sound decay in a room, measured as the slope of a line 0–10 dB decay below the maximum sound level. D50 is defined as the ratio of the early received sound energy (0–50 ms after direct sound arrival) to the total received energy. Clarity is defined as the ratio of the energy in the early sound (received in the first 80 ms) to that in the reverberant sound. STI is a measure of speech transmission quality, which indicates the degree to which a transmission channel degrades speech intelligibility. STI ranges from 0 to 1; a speech transferred through a channel with STI of 1 is perfectly intelligible, but the intelligibility reduces as the STI approaches zero. International standards and guidelines (e.g., ISO 18233) are available for the measurement of these characteristics.

Extensive researches are in progress, on the acoustic comfort in buildings. In recent works, Tong et al. [17] studied the acoustical performance of classrooms and laboratories in a public school exposed to traffic environment, while Jeong et al. [18] focused on the acoustic design and evaluation of a concert hall. Tan et al. [19] introduced application of building information modeling to improve indoor acoustic performance. Few other studies include those reported by Lam et al. [20], Imran et al. [21], and Renterghem [22].

### **6. Ergonomics**

Ergonomics deals with the design of objects, systems, and environment, in a manner that ensures human comfort. In fact, ergonomics encompasses all components of IEQ, simply because the prime objective of IEQ is human health and comfort. It covers diverse disciplines such as anatomy, physiology, psychology, and design. An indoor ergonomist should be specialized in the interrelationship between the human mind and body and the various aspects of a building such as architecture, interior design, building services, structure, materials, and microclimate. In general, environmental ergonomics deals with the interaction between people and their physical environment with particular importance on thermal comfort, lighting, noise, and vibration. Similar to ergonomics in a residential environment, ergonomics in offices and workplace is also a scientific discipline and a topic of research. Edmonds [23] defines the following factors that affect the workplace ergonomics: tasks, tools, equipment, area and space, environment, and organizational pattern. The Southeast Asian Network of Ergonomics Societies (SEANES) has introduced ergonomic checkpoints for indoor and outdoor workplaces for the purpose of motivating workers to recognize hazards in the work environment and adopt precautionary measures accordingly [24]. Similarly, Ushada et al. [25] developed environmental ergonomic control system for small and medium sized, by using worker workload and workstation temperature difference.

### **7. Electromagnetic field and radiation**

Electromagnetic field is created by moving electric charges, microwaves, radio waves, electrical currents, and transformers. The low-frequency electromagnetic radiation prevailing mostly in indoors (due to electrical appliances, computers, wireless devices, etc.) can have detrimental effect on human health, and there are international regulations to deal with this problem (e.g., International Radiation Protection Association (IRPA)) [26]. Most of the regulations agree that exposure to electromagnetic field beyond the safe range of 0–300 Hz is harmful for the human body [27]. The possibility of health hazards such as acute lymphoblastic leukemia in children due to electromagnetic field exposure was well established decades ago [28] and continues to be a significant topic of research [26, 29–31].

#### **8. Water quality**

Adequate, safe, and accessible supply of drinking water is vital for the sustenance of human life especially in indoor environments where access to natural sources of water such as wells, ponds, rivers, and lakes is limited. Drinking water

**5**

[53, 54].

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

ability [32].

identified.

**9. IEQ research trends**

**9.1 IEQ of common buildings**

quality has a direct impact on human health. Infants, young children, weak and elderly people, and those who live in unhygienic environment are largely prone to waterborne deceases [32]. There is no universally applicable legislative framework for the implementation of standards to maintain drinking water quality. An approach that works in one country or region may not be suitable for other countries. Therefore, each country should develop its own legislation according to its requirements and capacity for implementation. However, while developing standards, the most common aspects that need to be taken into account are microbial safety, chemical safety, radiological safety, disinfection, and accept-

A huge number of literatures are available on the research on various aspects of IEQ, and a comprehensive review of these literatures is beyond the scope of this chapter. Many researchers have compiled them in their review articles [7, 33–42]. However, a brief overview of the exemplary researches is presented here. Most of the researches were on post-occupancy evaluation (POE) on IEQ of different types of common buildings (e.g., healthcare, office, educational, residential, etc.), through field measurements and user satisfaction surveys, while many other researchers were interested on POE of sustainable and green buildings. In these researches, the findings are usually compared with the prevailing local or global (as applicable) standards, and recommendations are made to address the issues

Reynolds et al. [43] measured the physical, mechanical, and environmental factors affecting IEQ of office buildings in the United States (US). The measurements included endotoxin, total bioaerosols, and psychosocial parameters. Addressing the impact of IEQ on the occupant's productivity in offices, Kang et al. [44] investigated open-plan research offices in 19 Chinese universities by conducting survey on 231 subjects. The study identified five factors that significantly affected the office productivity, which are layout, air quality, thermal comfort, lighting, and acoustic comfort, where the acoustic comfort had the maximum impact. In a similar study [45], experiments were performed on the effect of indoor temperature on the IEQ user perception and productivity in office buildings, by choosing 9 females and 12 males. The parameters measured were air temperature, globe temperature, relative humidity, carbon dioxide (CO2) concentration, and lighting and noise comforts. The indoor air temperature was varied by keeping the other IEQ parameters fixed. It was shown that the thermal environment had a significant impact on the thermal comfort and other IEQ factors. Kim et al. [46] focused on the impact of IEQ and work stress on the physiological responses of office workers and concluded that the most noticeable result of the experiment in this study is that a high CO2 concentration and work stress could detrimentally influence the physiological and physiological responses, leading to abnormal variations in blood pressure. Similar studies on the effect of IEQ on office workers' performance are those reported by Haapakangas et al. [47], Suk [14], Zuo and Malone Beach [48], Ali et al. [49], Huang et al. [50], Frontczak et al. [51], Wong et al. [52], and Kosonen and Tan

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

quality has a direct impact on human health. Infants, young children, weak and elderly people, and those who live in unhygienic environment are largely prone to waterborne deceases [32]. There is no universally applicable legislative framework for the implementation of standards to maintain drinking water quality. An approach that works in one country or region may not be suitable for other countries. Therefore, each country should develop its own legislation according to its requirements and capacity for implementation. However, while developing standards, the most common aspects that need to be taken into account are microbial safety, chemical safety, radiological safety, disinfection, and acceptability [32].

### **9. IEQ research trends**

*Indoor Environmental Quality*

**6. Ergonomics**

Imran et al. [21], and Renterghem [22].

workstation temperature difference.

topic of research [26, 29–31].

**8. Water quality**

**7. Electromagnetic field and radiation**

Extensive researches are in progress, on the acoustic comfort in buildings. In recent works, Tong et al. [17] studied the acoustical performance of classrooms and laboratories in a public school exposed to traffic environment, while Jeong et al. [18] focused on the acoustic design and evaluation of a concert hall. Tan et al. [19] introduced application of building information modeling to improve indoor acoustic performance. Few other studies include those reported by Lam et al. [20],

Ergonomics deals with the design of objects, systems, and environment, in a manner that ensures human comfort. In fact, ergonomics encompasses all components of IEQ, simply because the prime objective of IEQ is human health and comfort. It covers diverse disciplines such as anatomy, physiology, psychology, and design. An indoor ergonomist should be specialized in the interrelationship between the human mind and body and the various aspects of a building such as architecture, interior design, building services, structure, materials, and microclimate. In general, environmental ergonomics deals with the interaction between people and their physical environment with particular importance on thermal comfort, lighting, noise, and vibration. Similar to ergonomics in a residential environment, ergonomics in offices and workplace is also a scientific discipline and a topic of research. Edmonds [23] defines the following factors that affect the workplace ergonomics: tasks, tools, equipment, area and space, environment, and organizational pattern. The Southeast Asian Network of Ergonomics Societies (SEANES) has introduced ergonomic checkpoints for indoor and outdoor workplaces for the purpose of motivating workers to recognize hazards in the work environment and adopt precautionary measures accordingly [24]. Similarly, Ushada et al. [25] developed environmental ergonomic control system for small and medium sized, by using worker workload and

Electromagnetic field is created by moving electric charges, microwaves, radio waves, electrical currents, and transformers. The low-frequency electromagnetic radiation prevailing mostly in indoors (due to electrical appliances, computers, wireless devices, etc.) can have detrimental effect on human health, and there are international regulations to deal with this problem (e.g., International Radiation Protection Association (IRPA)) [26]. Most of the regulations agree that exposure to electromagnetic field beyond the safe range of 0–300 Hz is harmful for the human body [27]. The possibility of health hazards such as acute lymphoblastic leukemia in children due to electromagnetic field exposure was well established decades ago [28] and continues to be a significant

Adequate, safe, and accessible supply of drinking water is vital for the sustenance of human life especially in indoor environments where access to natural sources of water such as wells, ponds, rivers, and lakes is limited. Drinking water

**4**

A huge number of literatures are available on the research on various aspects of IEQ, and a comprehensive review of these literatures is beyond the scope of this chapter. Many researchers have compiled them in their review articles [7, 33–42]. However, a brief overview of the exemplary researches is presented here. Most of the researches were on post-occupancy evaluation (POE) on IEQ of different types of common buildings (e.g., healthcare, office, educational, residential, etc.), through field measurements and user satisfaction surveys, while many other researchers were interested on POE of sustainable and green buildings. In these researches, the findings are usually compared with the prevailing local or global (as applicable) standards, and recommendations are made to address the issues identified.

#### **9.1 IEQ of common buildings**

Reynolds et al. [43] measured the physical, mechanical, and environmental factors affecting IEQ of office buildings in the United States (US). The measurements included endotoxin, total bioaerosols, and psychosocial parameters. Addressing the impact of IEQ on the occupant's productivity in offices, Kang et al. [44] investigated open-plan research offices in 19 Chinese universities by conducting survey on 231 subjects. The study identified five factors that significantly affected the office productivity, which are layout, air quality, thermal comfort, lighting, and acoustic comfort, where the acoustic comfort had the maximum impact. In a similar study [45], experiments were performed on the effect of indoor temperature on the IEQ user perception and productivity in office buildings, by choosing 9 females and 12 males. The parameters measured were air temperature, globe temperature, relative humidity, carbon dioxide (CO2) concentration, and lighting and noise comforts. The indoor air temperature was varied by keeping the other IEQ parameters fixed. It was shown that the thermal environment had a significant impact on the thermal comfort and other IEQ factors. Kim et al. [46] focused on the impact of IEQ and work stress on the physiological responses of office workers and concluded that the most noticeable result of the experiment in this study is that a high CO2 concentration and work stress could detrimentally influence the physiological and physiological responses, leading to abnormal variations in blood pressure. Similar studies on the effect of IEQ on office workers' performance are those reported by Haapakangas et al. [47], Suk [14], Zuo and Malone Beach [48], Ali et al. [49], Huang et al. [50], Frontczak et al. [51], Wong et al. [52], and Kosonen and Tan [53, 54].

Almeida and De Freitas [55] performed onsite measurements of temperature, relative humidity, CO2 concentration, and ventilation rates in the classrooms of nine retrofitted and non-retrofitted school buildings in Portugal. The measurements were done during winter, mid-season, and summer conditions. In their observations, the non-retrofitted schools lack in the desired IEQ level, while retrofitted buildings did not have mechanical ventilation systems. Shan et al. [56] investigated the influence of indoor thermal condition and IAQ on students' health and performance through life cycle costing (LCC) approach, by considering two university classrooms. In the proposed LCC approach, metrics were defined for students' health (or well-being) and performance, which were subsequently translated into monetary values to quantify the impact of IEQ. The indicators considered for health and performance were sick leave and students' grade achievement, respectively. The findings of this study indicated the significance of incorporating students' health and performance into the design and operation of educational buildings. Few other researches focusing on educational buildings are those of Kim et al. [57], Vilčeková et al. [58], Jamaludin et al. [59], De Giuli et al. [60], and Nasir et al. [61].

Lai et al. [62] developed an IEQ assessment model for residential buildings in Hong Kong. The empirical model developed by using the data collected from 125 occupants from 32 residential buildings was useful to assess the acceptance level in terms of operative temperature, CO2 concentration, and acoustic and lighting comforts. The study revealed that both thermal and acoustic comforts were the decisive contributors, while IAQ was the least. Huang et al. [63] studied the effect of IEQ of long-term care (LTC) facilities on the occupants' behavior, through survey. Garcia et al. [64] performed retrospective descriptive secondary analyses on the data collected (air exchange rates, temperature, and humidity) from indoor, outdoor, and personal air in residential buildings. Addressing the IEQ of healthcare buildings, Andrade et al. [65] performed user perception survey on hospital buildings in Portugal, considering physical and social aspects. De Giuli et al. [66] conducted survey and field measurements of three medical wards in a general hospital in Italy.

#### **9.2 IEQ of sustainable and green buildings**

As already mentioned, the IEQ level of sustainable and green buildings has been a concern of many researchers. Choi [67] proposed an explanatory model to understand the relationships among the occupants' perceptions on the IEQ level, overall facility, productivity, and sustainability ethic, in sustainable buildings. Hwang and Kim [68] performed post-occupancy evaluation (POE) of open offices in a Korean building that was certified as "1st Grade Building" Green. The studied parameters were indoor temperature, relative humidity, vertical temperature distribution, air velocity, predicted mean vote (PMV), radiant temperature, outdoor temperature, and humidity. Measurements were also done on the major indoor air contaminants, illuminance, and SPL. An online survey was also conducted among the occupants to know their perception on the IEQ level. The performance of this building was found to be satisfactory in terms of PMV and lighting, while it was weak for IAQ and acoustic comfort. Ravindu et al. [69] explored the IEQ level of a LEED-certified factory building in Sri Lanka, through questionnaire survey. They found that the building was performing low with regard to thermal comfort, ventilation, and ability to control indoor the environment. Altomonte et al. [3] studied the occupant satisfaction on IEQ in LEED- and BREEAM-certified office buildings and highlighted the importance of incorporating IEQ in the criteria for sustainable and green building certifications.

**7**

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

Indoor environmental quality is a very important scientific domain that deals with various aspects that govern the health, comfort, and productivity of the occupants and determine the value of a building. However, even though there is increasing awareness on the demand for sustainable, green, and highperformance buildings, ensuring the desired level of IEQ is often not given the deserving care. Consequently, most of the sustainable and green buildings lack in complying with the IEQ requirements. The building owners should rewrite their mindset to take into account the enormous potential for monetary returns and health benefits through improving the IEQ of the building. The following good practices are generally recommended to ensure a comfortable level of

• Follow scientific practices of design, construction, renovation, operation, and

• Enhance the esthetics and indoor environment by proper integration of natural

• Minimize the dependence of artificial lighting and electrical equipment such as air conditioner, elevator, and fans, with a view to improve human health and

• Ensure thermal comfort through proper design of the interior and microclimate.

• Facilitate proper ventilation and maintain acceptable air quality, by following

• Adopt proper design and maintenance of HVAC system, and proper design and construction of the envelope, to prevent mold, fungi, airborne bacteria, and

• Minimize the spread of pathogens by minimizing exposure to washrooms and

• Avoid using products and materials, which contain harmful ingredients (such

• Ensure noise comfort and privacy, by suitably adopting the materials for walls,

• Avoid unpleasant odors through selective use of products, regular and safe waste disposal, careful selection of cleaning products, isolation of contami-

• Establish a comfortable and healthy indoor lighting, through optimum integration of artificial and natural lightings, and use of energy-efficient, user-

floors, and ceiling, and other standard means for acoustic comfort.

maintenance, in compliance with the international standards.

• Adopt "source control" by minimizing the causes that lead to poor IEQ.

**10. Concluding remarks**

and man-made facilities.

standard guidelines.

radon.

minimize energy consumption.

by proper maintenance procedures.

as formaldehyde) and produce harmful emissions.

nants, prohibition of smoking, and related measures.

friendly, and eco-friendly artificial lighting.

IEQ:

## **10. Concluding remarks**

*Indoor Environmental Quality*

Almeida and De Freitas [55] performed onsite measurements of temperature, relative humidity, CO2 concentration, and ventilation rates in the classrooms of nine retrofitted and non-retrofitted school buildings in Portugal. The measurements were done during winter, mid-season, and summer conditions. In their observations, the non-retrofitted schools lack in the desired IEQ level, while retrofitted buildings did not have mechanical ventilation systems. Shan et al. [56] investigated the influence of indoor thermal condition and IAQ on students' health and performance through life cycle costing (LCC) approach, by considering two university classrooms. In the proposed LCC approach, metrics were defined for students' health (or well-being) and performance, which were subsequently translated into monetary values to quantify the impact of IEQ. The indicators considered for health and performance were sick leave and students' grade achievement, respectively. The findings of this study indicated the significance of incorporating students' health and performance into the design and operation of educational buildings. Few other researches focusing on educational buildings are those of Kim et al. [57], Vilčeková

et al. [58], Jamaludin et al. [59], De Giuli et al. [60], and Nasir et al. [61].

**9.2 IEQ of sustainable and green buildings**

sustainable and green building certifications.

Lai et al. [62] developed an IEQ assessment model for residential buildings in Hong Kong. The empirical model developed by using the data collected from 125 occupants from 32 residential buildings was useful to assess the acceptance level in terms of operative temperature, CO2 concentration, and acoustic and lighting comforts. The study revealed that both thermal and acoustic comforts were the decisive contributors, while IAQ was the least. Huang et al. [63] studied the effect of IEQ of long-term care (LTC) facilities on the occupants' behavior, through survey. Garcia et al. [64] performed retrospective descriptive secondary analyses on the data collected (air exchange rates, temperature, and humidity) from indoor, outdoor, and personal air in residential buildings. Addressing the IEQ of healthcare buildings, Andrade et al. [65] performed user perception survey on hospital buildings in Portugal, considering physical and social aspects. De Giuli et al. [66] conducted survey and field measurements of three medical wards in a general hospital in Italy.

As already mentioned, the IEQ level of sustainable and green buildings has been a concern of many researchers. Choi [67] proposed an explanatory model to understand the relationships among the occupants' perceptions on the IEQ level, overall facility, productivity, and sustainability ethic, in sustainable buildings. Hwang and Kim [68] performed post-occupancy evaluation (POE) of open offices in a Korean building that was certified as "1st Grade Building" Green. The studied parameters were indoor temperature, relative humidity, vertical temperature distribution, air velocity, predicted mean vote (PMV), radiant temperature, outdoor temperature, and humidity. Measurements were also done on the major indoor air contaminants, illuminance, and SPL. An online survey was also conducted among the occupants to know their perception on the IEQ level. The performance of this building was found to be satisfactory in terms of PMV and lighting, while it was weak for IAQ and acoustic comfort. Ravindu et al. [69] explored the IEQ level of a LEED-certified factory building in Sri Lanka, through questionnaire survey. They found that the building was performing low with regard to thermal comfort, ventilation, and ability to control indoor the environment. Altomonte et al. [3] studied the occupant satisfaction on IEQ in LEED- and BREEAM-certified office buildings and highlighted the importance of incorporating IEQ in the criteria for

**6**

Indoor environmental quality is a very important scientific domain that deals with various aspects that govern the health, comfort, and productivity of the occupants and determine the value of a building. However, even though there is increasing awareness on the demand for sustainable, green, and highperformance buildings, ensuring the desired level of IEQ is often not given the deserving care. Consequently, most of the sustainable and green buildings lack in complying with the IEQ requirements. The building owners should rewrite their mindset to take into account the enormous potential for monetary returns and health benefits through improving the IEQ of the building. The following good practices are generally recommended to ensure a comfortable level of IEQ:


## **Author details**

Muhammad Abdul Mujeebu Department of Building Engineering, College of Architecture and Planning, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia

\*Address all correspondence to: mmalmujeebu@uod.edu.sa

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**9**

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

Health Organization Regional Office for

[9] Becher R, Øvrevik J, Schwarze PE, Nilsen S, Hongslo JK, Bakke JV. Do carpets impair indoor air quality and cause adverse health outcomes: A review. International Journal of Environmental Research and Public

[10] Djongyang N, Tchinda R, Njomo D. Thermal comfort: A review paper. Renewable and Sustainable Energy Reviews. 2010;**14**(9):2626-2640

[11] Taleghani M, Tenpierik M, Kurvers S, Van Den Dobbelsteen A. A review into thermal comfort in buildings. Renewable and Sustainable Energy

[12] Carlucci S, Causone F, De Rosa F, Pagliano L. A review of indices for assessing visual comfort with a view to their use in optimization processes to support building integrated design. Renewable and Sustainable Energy Reviews. 2015;**47**(7491):1016-1033

[13] Xue P, Mak CM, Huang Y. Quantification of luminous comfort with dynamic daylight metrics in residential buildings. Energy and Buildings. 2016;**117**:99-108

[14] Suk JY. Luminance and vertical eye illuminance thresholds for occupants' visual comfort in daylit office environments. Building and Environment. 2019;**148**:107-115

[15] Suk JY, Schiler M, Kensek K. Absolute glare factor and relative glare factor based metric: Predicting and quantifying levels of daylight glare in office space. Energy and Buildings.

[16] Galatioto A, Beccali M. Aspects and issues of daylighting assessment:

2016;**130**:8-19

Europe; 2009

Health. 2018;**15**(2):E184

Reviews. 2013;**26**:201-215

[1] Almeida RMSF, de Freitas VP, Delgado JMPQ. School buildings rehabilitation-indoor environmental quality and enclosure optimization. In: Almeida RMSF, de Freitas VP, Delgado JMPQ , editors. School Buildings Rehabilitation. Switzerland AG: Springer Nature; 2015. pp. 5-17

[2] Spengler JD, Chen QY. Indoor air quality factors in designing a healthy building. Annual Review of Energy and the Environment. Amsterdam, Netherlands: Elsevier

[3] Altomonte S, Saadouni S, Kent MG, Schiavon S. Satisfaction with indoor environmental quality in BREEAM and non-BREEAM certified office buildings. Architectural Science Review.

Rismanchi B. Ten questions concerning

[5] Holmgren M, Kabanshi A, Sörqvist P.

buildings: Distinguishing physical and psychological factors. Building and Environment. 2017;**114**:140-147

[6] Persily AK, Emmerich SJ. Indoor air quality in sustainable, energy efficient buildings. HVAC & R Research.

[7] Al horr Y, Arif M, Katafygiotou M, Mazroei A, Kaushik A, Elsarrag E. Impact of indoor environmental quality on occupant well-being and comfort: A review of the literature. International Journal of Sustainable Built

Environment. 2016;**5**(1):1-11

[8] Heseltine E, Rosen J. WHO Guidelines for Indoor Air Quality: Dampness and Mould. Germany: World

B.V; 2000;**25**:567-601

2017;**60**(4):343-355

[4] Steinemann A, Wargocki P,

green buildings and indoor air quality. Building and Environment.

Occupant perception of 'green'

2017;**112**(2017):351-358

2012;**18**(1-2):4-20

**References**

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

### **References**

*Indoor Environmental Quality*

indoor environment.

facilities.

**8**

**Author details**

Muhammad Abdul Mujeebu

provided the original work is properly cited.

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Department of Building Engineering, College of Architecture and Planning, Imam

Abdulrahman Bin Faisal University, Dammam, Saudi Arabia

\*Address all correspondence to: mmalmujeebu@uod.edu.sa

• Maintain availability and accessibility of safe and clean drinking water in

• Restrict and be aware of exposure to electromagnetic field and radiation, in the

• Ensure indoor ergonomic quality by providing ergonomic furniture and other

• Regularly conduct occupant surveys and post-occupancy evaluations.

compliance with the water quality standards.

[1] Almeida RMSF, de Freitas VP, Delgado JMPQ. School buildings rehabilitation-indoor environmental quality and enclosure optimization. In: Almeida RMSF, de Freitas VP, Delgado JMPQ , editors. School Buildings Rehabilitation. Switzerland AG: Springer Nature; 2015. pp. 5-17

[2] Spengler JD, Chen QY. Indoor air quality factors in designing a healthy building. Annual Review of Energy and the Environment. Amsterdam, Netherlands: Elsevier B.V; 2000;**25**:567-601

[3] Altomonte S, Saadouni S, Kent MG, Schiavon S. Satisfaction with indoor environmental quality in BREEAM and non-BREEAM certified office buildings. Architectural Science Review. 2017;**60**(4):343-355

[4] Steinemann A, Wargocki P, Rismanchi B. Ten questions concerning green buildings and indoor air quality. Building and Environment. 2017;**112**(2017):351-358

[5] Holmgren M, Kabanshi A, Sörqvist P. Occupant perception of 'green' buildings: Distinguishing physical and psychological factors. Building and Environment. 2017;**114**:140-147

[6] Persily AK, Emmerich SJ. Indoor air quality in sustainable, energy efficient buildings. HVAC & R Research. 2012;**18**(1-2):4-20

[7] Al horr Y, Arif M, Katafygiotou M, Mazroei A, Kaushik A, Elsarrag E. Impact of indoor environmental quality on occupant well-being and comfort: A review of the literature. International Journal of Sustainable Built Environment. 2016;**5**(1):1-11

[8] Heseltine E, Rosen J. WHO Guidelines for Indoor Air Quality: Dampness and Mould. Germany: World Health Organization Regional Office for Europe; 2009

[9] Becher R, Øvrevik J, Schwarze PE, Nilsen S, Hongslo JK, Bakke JV. Do carpets impair indoor air quality and cause adverse health outcomes: A review. International Journal of Environmental Research and Public Health. 2018;**15**(2):E184

[10] Djongyang N, Tchinda R, Njomo D. Thermal comfort: A review paper. Renewable and Sustainable Energy Reviews. 2010;**14**(9):2626-2640

[11] Taleghani M, Tenpierik M, Kurvers S, Van Den Dobbelsteen A. A review into thermal comfort in buildings. Renewable and Sustainable Energy Reviews. 2013;**26**:201-215

[12] Carlucci S, Causone F, De Rosa F, Pagliano L. A review of indices for assessing visual comfort with a view to their use in optimization processes to support building integrated design. Renewable and Sustainable Energy Reviews. 2015;**47**(7491):1016-1033

[13] Xue P, Mak CM, Huang Y. Quantification of luminous comfort with dynamic daylight metrics in residential buildings. Energy and Buildings. 2016;**117**:99-108

[14] Suk JY. Luminance and vertical eye illuminance thresholds for occupants' visual comfort in daylit office environments. Building and Environment. 2019;**148**:107-115

[15] Suk JY, Schiler M, Kensek K. Absolute glare factor and relative glare factor based metric: Predicting and quantifying levels of daylight glare in office space. Energy and Buildings. 2016;**130**:8-19

[16] Galatioto A, Beccali M. Aspects and issues of daylighting assessment: A review study. Renewable and Sustainable Energy Reviews. 2016;**66**:852-860

[17] Tong Y, Abu Bakar H, Sari KM, Ewon U, Labeni M, Fauzan N. Effect of urban noise to the acoustical performance of the secondary school's learning spaces—A case study in Batu Pahat. IOP Conference Series: Materials Science and Engineering. 2017;**271**(012029):1-8

[18] Jeong K , Hong T, Kim SH, Kim J, Lee S. "Acoustic design of a classical concert hall and evaluation of its acoustic performance—A case study," Preprint, vol. 2018050309, no. May, pp. 1-12, 2018

[19] Tan Y, Fang Y, Zhou T, Wang Q, Cheng JCP, Kong H. Improve indoor acoustics performance by using building information modeling. In: 34th International Symposium on Automation and Robotics in Construction (ISARC 2017); 28 June-1 July 2017; Taipei, Taiwan. 2017

[20] Lam A, Hodgson M, Prodi N, Visentin C. Effects of classroom acoustics on speech intelligibility and response time: A comparison between native and non-native listeners. Building Acoustics. 2018;**25**(1):35-42

[21] Imran M, Heimes A, Vorländer M. Auralization of airborne sound transmission for coupled rooms in virtual reality. In: 44th Annual Conference on Acoustics (DAGA 2018); 19-22 March 2018; Munich, Germany. 2018

[22] Van Renterghem T. Improving the noise reduction by green roofs due to solar panels and substrate shaping. Building Acoustics. 2018;**25**(3):219-232

[23] Edmonds J. Overview of human factors engineering. In: Human Factors in the Chemical and Process Industries. Amsterdam, Netherlands: Elsevier B.V., Elsevier Inc.; 2016. pp. 153-167

[24] Khalid H, Kogi K, Helander M. Ergonomics intervention of workplaces using SEANES ergonomic checkpoints. In: 20th Congress of the International Ergonomics Association (IEA 2018); 2018. pp. 1125-1134

[25] Ushada M, Suyantohadi A, Khuriyati N, Okayama T. Identification of environmental ergonomics control system for Indonesian SMEs. In: 3rd International Conference on Control, Automation and Robotics; 24-26 April 2017; Nagoya, Japan. 2017. pp. 453-456

[26] Fayed I, Bedda M. Electromagnetic radiation and its effects on human beings: Survey and environmental recommendations. In: 15th Scientific Symposium for Hajj, Umrah and Madinah visit—Scientific Portal for 1436AH; 27-28 May 2015; Saudi Arabia. 2015. pp. 35-47

[27] Valberg PA, van Deventer TE, Repacholi MH. Workgroup report: Base stations and wireless networks- -radiofrequency (RF) exposures and health consequences. Environmental Health Perspectives. 2007;**115**(3):416

[28] Linet MS, Hatch EE, Kleinerman RA, Robison LL, Kaune WT, Friedman DR, et al. Residential exposure to magnetic fields and acute lymphoblastic leukemia in children. The New England Journal of Medicine. 1997;**337**(1):1-8

[29] Kheifets L, Repacholi M, Saunders R, Van Deventer E. The sensitivity of children to electromagnetic fields. Pediatrics. 2005;**116**:303-313

[30] Verloock L, Joseph W, Vermeeren G, Martens L. Procedure for assessment of general public exposure from WLAN in offices and in wireless sensor network testbed. Health Physics. 2010;**98**(4):628-638

**11**

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

> review of the literature. Building and Environment. 2016;**105**:369-389

[40] Kolokotsa D, Santamouris M. Review of the indoor environmental quality and energy consumption studies for low income households in Europe. Science of the Total Environment.

[41] Sarbu I, Sebarchievici C. Aspects of indoor environmental quality assessment in buildings. Energy and

[42] Heinzerling D, Schiavon S, Webster T, Arens E. Indoor environmental quality assessment models: A literature review and a proposed weighting and classification scheme. Building and Environment. 2013;**70**:210-222

[43] Reynolds SJ, Black DW, Borin SS, Breuer G, Burmeister LF, Fuortes LJ, et al. Indoor environmental quality in six commercial office buildings in the Midwest United States. Applied Occupational and Environmental Hygiene. 2010;**16**(11):1065-1077

[44] Kang S, Ou D, Mak CM. The impact of indoor environmental quality on work productivity in university openplan research offices. Building and Environment. 2017;**124**:78-89

[45] Geng Y, Ji W, Lin B, Zhu Y. The impact of thermal environment on occupant IEQ perception and productivity. Building and Environment. 2017;**121**:158-167

[46] Kim J, Kong M, Hong T, Jeong K, Lee M. Physiological response of building occupants based on their activity and the indoor environmental quality condition changes. Building and

Environment. 2018;**145**:96-103

[47] Haapakangas A, Hallman DM, Mathiassen SE, Jahncke H. Self-rated productivity and employee wellbeing in activity-based offices: The

Buildings. 2013;**60**:410-419

2015;**536**:316-330

field exposures in kindergarten children. Journal of Exposure Science & Environmental Epidemiology.

[32] WHO. Guidelines for Drinking-Water quality: First Addendum to Third Edition, Vol 1—Recommendations. Geneva, Switzerland: World Health

[33] Bluyssen PM, Janssen S, van den Brink LH, de Kluizenaar Y. Assessment of wellbeing in an indoor office environment. Building and Environment. 2011;**46**(12):2632-2640

[34] Yu CWF, Jeong TK. Building environmental assessment schemes for rating of IAQ in sustainable buildings. Indoor and Built Environment.

[35] Kim J, de Dear R, Cândido C, Zhang H, Arens E. Gender differences in office occupant perception of indoor environmental quality (IEQ ). Building and Environment. 2013;**70**:245-256

[36] Sakhare VV, Ralegaonkar RV. Indoor environmental quality:

Review of parameters and assessment models. Architectural Science Review.

[37] Rashid M. A review of the empirical literature on the relationships between indoor environment and stress in health care and office settings— Problems and prospects of sharing evidence. Environment and Behavior.

[38] Nimlyat PS, Kandar MZ. Appraisal of indoor environmental quality (IEQ ) in healthcare facilities: A literature review. Sustainable Cities and Society.

[39] Al Horr Y, Arif M, Kaushik A, Mazroei A, Katafygiotou M, Elsarrag E. Occupant productivity and office indoor environment quality: A

2017;**27**(5):497-504

Organization; 2006

2011;**20**(1):5-15

2014;**57**(2):147-154

2015;**40**(2):21

2015;**17**:61-68

[31] Bhatt CR, Redmayne M, Billah B, Abramson MJ, Benke G. Radiofrequency-electromagnetic *Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

field exposures in kindergarten children. Journal of Exposure Science & Environmental Epidemiology. 2017;**27**(5):497-504

*Indoor Environmental Quality*

2016;**66**:852-860

2017;**271**(012029):1-8

pp. 1-12, 2018

A review study. Renewable and Sustainable Energy Reviews.

[24] Khalid H, Kogi K, Helander M. Ergonomics intervention of workplaces using SEANES ergonomic checkpoints. In: 20th Congress of the International Ergonomics Association (IEA 2018);

[25] Ushada M, Suyantohadi A,

Khuriyati N, Okayama T. Identification of environmental ergonomics control system for Indonesian SMEs. In: 3rd International Conference on Control, Automation and Robotics; 24-26 April 2017; Nagoya, Japan. 2017. pp. 453-456

[26] Fayed I, Bedda M. Electromagnetic radiation and its effects on human beings: Survey and environmental recommendations. In: 15th Scientific Symposium for Hajj, Umrah and Madinah visit—Scientific Portal for 1436AH; 27-28 May 2015; Saudi Arabia.

[27] Valberg PA, van Deventer TE, Repacholi MH. Workgroup report: Base stations and wireless networks- -radiofrequency (RF) exposures and health consequences. Environmental Health Perspectives. 2007;**115**(3):416

[28] Linet MS, Hatch EE, Kleinerman RA, Robison LL, Kaune WT, Friedman DR, et al. Residential exposure to magnetic fields and acute lymphoblastic leukemia in children. The New England Journal of Medicine. 1997;**337**(1):1-8

[29] Kheifets L, Repacholi M, Saunders R, Van Deventer E. The sensitivity of children to electromagnetic fields.

[30] Verloock L, Joseph W, Vermeeren G, Martens L. Procedure for assessment

of general public exposure from WLAN in offices and in wireless sensor network testbed. Health Physics.

[31] Bhatt CR, Redmayne M, Billah B, Abramson MJ, Benke G. Radiofrequency-electromagnetic

2010;**98**(4):628-638

Pediatrics. 2005;**116**:303-313

2018. pp. 1125-1134

2015. pp. 35-47

[17] Tong Y, Abu Bakar H, Sari KM, Ewon U, Labeni M, Fauzan N. Effect of urban noise to the acoustical performance of the secondary school's learning spaces—A case study in Batu Pahat. IOP Conference Series: Materials Science and Engineering.

[18] Jeong K , Hong T, Kim SH, Kim J, Lee S. "Acoustic design of a classical concert hall and evaluation of its acoustic performance—A case study," Preprint, vol. 2018050309, no. May,

[19] Tan Y, Fang Y, Zhou T, Wang Q, Cheng JCP, Kong H. Improve indoor acoustics performance by using building information modeling. In: 34th International Symposium on Automation and Robotics in Construction (ISARC 2017); 28 June-1

July 2017; Taipei, Taiwan. 2017

Acoustics. 2018;**25**(1):35-42

2018; Munich, Germany. 2018

[20] Lam A, Hodgson M, Prodi N, Visentin C. Effects of classroom acoustics on speech intelligibility and response time: A comparison between native and non-native listeners. Building

[21] Imran M, Heimes A, Vorländer M. Auralization of airborne sound

transmission for coupled rooms in virtual reality. In: 44th Annual Conference on Acoustics (DAGA 2018); 19-22 March

[22] Van Renterghem T. Improving the noise reduction by green roofs due to solar panels and substrate shaping. Building Acoustics. 2018;**25**(3):219-232

[23] Edmonds J. Overview of human factors engineering. In: Human Factors in the Chemical and Process Industries. Amsterdam, Netherlands: Elsevier B.V.,

Elsevier Inc.; 2016. pp. 153-167

**10**

[32] WHO. Guidelines for Drinking-Water quality: First Addendum to Third Edition, Vol 1—Recommendations. Geneva, Switzerland: World Health Organization; 2006

[33] Bluyssen PM, Janssen S, van den Brink LH, de Kluizenaar Y. Assessment of wellbeing in an indoor office environment. Building and Environment. 2011;**46**(12):2632-2640

[34] Yu CWF, Jeong TK. Building environmental assessment schemes for rating of IAQ in sustainable buildings. Indoor and Built Environment. 2011;**20**(1):5-15

[35] Kim J, de Dear R, Cândido C, Zhang H, Arens E. Gender differences in office occupant perception of indoor environmental quality (IEQ ). Building and Environment. 2013;**70**:245-256

[36] Sakhare VV, Ralegaonkar RV. Indoor environmental quality: Review of parameters and assessment models. Architectural Science Review. 2014;**57**(2):147-154

[37] Rashid M. A review of the empirical literature on the relationships between indoor environment and stress in health care and office settings— Problems and prospects of sharing evidence. Environment and Behavior. 2015;**40**(2):21

[38] Nimlyat PS, Kandar MZ. Appraisal of indoor environmental quality (IEQ ) in healthcare facilities: A literature review. Sustainable Cities and Society. 2015;**17**:61-68

[39] Al Horr Y, Arif M, Kaushik A, Mazroei A, Katafygiotou M, Elsarrag E. Occupant productivity and office indoor environment quality: A

review of the literature. Building and Environment. 2016;**105**:369-389

[40] Kolokotsa D, Santamouris M. Review of the indoor environmental quality and energy consumption studies for low income households in Europe. Science of the Total Environment. 2015;**536**:316-330

[41] Sarbu I, Sebarchievici C. Aspects of indoor environmental quality assessment in buildings. Energy and Buildings. 2013;**60**:410-419

[42] Heinzerling D, Schiavon S, Webster T, Arens E. Indoor environmental quality assessment models: A literature review and a proposed weighting and classification scheme. Building and Environment. 2013;**70**:210-222

[43] Reynolds SJ, Black DW, Borin SS, Breuer G, Burmeister LF, Fuortes LJ, et al. Indoor environmental quality in six commercial office buildings in the Midwest United States. Applied Occupational and Environmental Hygiene. 2010;**16**(11):1065-1077

[44] Kang S, Ou D, Mak CM. The impact of indoor environmental quality on work productivity in university openplan research offices. Building and Environment. 2017;**124**:78-89

[45] Geng Y, Ji W, Lin B, Zhu Y. The impact of thermal environment on occupant IEQ perception and productivity. Building and Environment. 2017;**121**:158-167

[46] Kim J, Kong M, Hong T, Jeong K, Lee M. Physiological response of building occupants based on their activity and the indoor environmental quality condition changes. Building and Environment. 2018;**145**:96-103

[47] Haapakangas A, Hallman DM, Mathiassen SE, Jahncke H. Self-rated productivity and employee wellbeing in activity-based offices: The

role of environmental perceptions and workspace use. Building and Environment. 2018;**145**:115-124

[48] Zuo Q, Malone Beach EE. Assessing staff satisfaction with indoor environmental quality in assisted living facilities. Journal of Interior Design. 2017;**42**(1):67-84

[49] Ali AS, Chua SJL, Lim MEL. The effect of physical environment comfort on employees' performance in office buildings: A case study of three public universities in Malaysia. Structural Survey. 2015;**33**(4-5):294-308

[50] Huang L, Zhu Y, Ouyang Q, Cao B. A study on the effects of thermal, luminous, and acoustic environments on indoor environmental comfort in offices. Building and Environment. 2012;**49**(1):304-309

[51] Frontczak M, Schiavon S, Goins J, Arens E, Zhang H, Wargocki P. Quantitative relationships between occupant satisfaction and satisfaction aspects of indoor environmental quality and building design. Indoor Air. 2012;**22**(2):119-131

[52] Wong LT, Mui KW, Hui PS. A multivariate-logistic model for acceptance of indoor environmental quality (IEQ ) in offices. Building and Environment. 2008;**43**(1):1-6

[53] Kosonen R, Tan F. Assessment of productivity loss in airconditioned buildings using PMV index. Energy and Buildings. 2004;**36**(10):987-993

[54] Kosonen R, Tan F. The effect of perceived indoor air quality on productivity loss. Energy and Buildings. 2004;**36**(10):981-986

[55] Almeida RMSF, De Freitas VP. Indoor environmental quality of classrooms in Southern European

climate. Energy and Buildings. 2014;**81**:127-140

[56] Shan X, Melina AN, Yang EH. Impact of indoor environmental quality on students' wellbeing and performance in educational building through life cycle costing perspective. Journal of Cleaner Production. 2018;**204**:298-309

[57] Kim J, Hong T, Jeong J, Lee M, Lee M, Jeong K, et al. Establishment of an optimal occupant behavior considering the energy consumption and indoor environmental quality by region. Applied Energy. 2017;**204**:1431-1443

[58] Vilčeková S, Kapalo P, Mečiarová Ľ, Burdová EK, Imreczeová V. Investigation of indoor environment quality in classroom-case study. Procedia Engineering. 2017;**190**:496-503

[59] Jamaludin NM, Mahyuddin N, Akashah FW. Assessment of indoor environmental quality (IEQ ): Students well-being in University classroom with the application of landscaping. MATEC Web of Conferences. 2016;**66**:00061

[60] De Giuli V, Da Pos O, De Carli M. Indoor environmental quality and pupil perception in Italian primary schools. Building and Environment. 2012;**56**:335-345

[61] Nasir ARM, Musa AR, Che-Ani AI, Utaberta N, Abdullah NAG, Tawil NM. Identification of indoor environmental quality (IEQ ) parameter in creating conducive learning environment for architecture studio. Procedia Engineering. 2011;**20**:354-362

[62] Lai ACK, Mui KW, Wong LT, Law LY. An evaluation model for indoor environmental quality (IEQ ) acceptance in residential buildings. Energy and Buildings. 2009;**41**(9):930-936

[63] Huang YC, Chu CL, Chang Lee SN, Lan SJ, Hsieh CH, Hsieh YP. Building

**13**

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

users' perceptions of importance of indoor environmental quality in long-term care facilities. Building and Environment. 2013;**67**:224-230

Journal of Biometeorology.

2017;**61**(3):513-525

2012;**32**(2):97-111

of Minnesota; 2011

[64] Garcia F, Shendell DG, Madrigano J. Relationship among environmental quality variables, housing variables, and residential needs: A secondary analysis of the relationship among indoor, outdoor, and personal air (RIOPA) concentrations database. International

[65] Andrade C, Lima ML, Fornara F, Bonaiuto M. Users' views of hospital environmental quality: Validation of the perceived hospital environment quality indicators (PHEQIs). Journal of Environmental Psychology.

[66] De Giuli V, Zecchin R, Salmaso L, Corain L, De Carli M. Measured and perceived indoor environmental quality: Padua Hospital case study. Building and

[67] Choi S. The relationships among indoor environmental quality, occupant satisfaction, work performance, and sustainability ethic in sustainable buildings [PhD thesis]. The University

[68] Hwang T, Kim JT. Assessment of indoor environmental quality in open-plan offices. Indoor and Built Environment. 2013;**22**(1):139-156

[69] Ravindu S, Rameezdeen R, Zuo J, Zhou Z, Chandratilake R. Indoor environment quality of green buildings: Case study of an LEED platinum certified factory in a warm humid tropical climate. Building and Environment. 2015;**84**:105-113

Environment. 2013;**59**:211-226

*Introductory Chapter: Indoor Environmental Quality DOI: http://dx.doi.org/10.5772/intechopen.83612*

users' perceptions of importance of indoor environmental quality in long-term care facilities. Building and Environment. 2013;**67**:224-230

*Indoor Environmental Quality*

role of environmental perceptions and workspace use. Building and Environment. 2018;**145**:115-124

staff satisfaction with indoor

2017;**42**(1):67-84

2012;**49**(1):304-309

2012;**22**(2):119-131

[48] Zuo Q, Malone Beach EE. Assessing

climate. Energy and Buildings.

[56] Shan X, Melina AN, Yang EH. Impact of indoor environmental quality on students' wellbeing and performance in educational building through life cycle costing perspective. Journal of Cleaner Production. 2018;**204**:298-309

[57] Kim J, Hong T, Jeong J, Lee M, Lee M, Jeong K, et al. Establishment of an optimal occupant behavior considering the energy consumption and indoor environmental quality by region. Applied Energy. 2017;**204**:1431-1443

[58] Vilčeková S, Kapalo P, Mečiarová Ľ, Burdová EK, Imreczeová V. Investigation of indoor environment quality in classroom-case study.

Procedia Engineering. 2017;**190**:496-503

[59] Jamaludin NM, Mahyuddin N, Akashah FW. Assessment of indoor environmental quality (IEQ ): Students well-being in University classroom with the application of landscaping. MATEC Web of Conferences. 2016;**66**:00061

[60] De Giuli V, Da Pos O, De Carli M. Indoor environmental quality and pupil perception in Italian primary schools. Building and Environment.

[61] Nasir ARM, Musa AR, Che-Ani AI, Utaberta N, Abdullah NAG, Tawil NM. Identification of indoor environmental quality (IEQ ) parameter

[62] Lai ACK, Mui KW, Wong LT, Law LY. An evaluation model for indoor environmental quality (IEQ ) acceptance in residential buildings. Energy and Buildings. 2009;**41**(9):930-936

[63] Huang YC, Chu CL, Chang Lee SN, Lan SJ, Hsieh CH, Hsieh YP. Building

in creating conducive learning environment for architecture studio. Procedia Engineering. 2011;**20**:354-362

2012;**56**:335-345

2014;**81**:127-140

environmental quality in assisted living facilities. Journal of Interior Design.

[49] Ali AS, Chua SJL, Lim MEL. The effect of physical environment comfort on employees' performance in office buildings: A case study of three public universities in Malaysia. Structural Survey. 2015;**33**(4-5):294-308

[50] Huang L, Zhu Y, Ouyang Q, Cao B. A study on the effects of thermal, luminous, and acoustic environments on indoor environmental comfort in offices. Building and Environment.

[51] Frontczak M, Schiavon S, Goins J, Arens E, Zhang H, Wargocki P. Quantitative relationships between occupant satisfaction and satisfaction aspects of indoor environmental quality and building design. Indoor Air.

[52] Wong LT, Mui KW, Hui PS. A multivariate-logistic model for acceptance of indoor environmental quality (IEQ ) in offices. Building and

Environment. 2008;**43**(1):1-6

of productivity loss in air-

2004;**36**(10):987-993

2004;**36**(10):981-986

[53] Kosonen R, Tan F. Assessment

conditioned buildings using PMV index. Energy and Buildings.

[54] Kosonen R, Tan F. The effect of perceived indoor air quality on productivity loss. Energy and Buildings.

[55] Almeida RMSF, De Freitas VP. Indoor environmental quality of classrooms in Southern European

**12**

[64] Garcia F, Shendell DG, Madrigano J. Relationship among environmental quality variables, housing variables, and residential needs: A secondary analysis of the relationship among indoor, outdoor, and personal air (RIOPA) concentrations database. International Journal of Biometeorology. 2017;**61**(3):513-525

[65] Andrade C, Lima ML, Fornara F, Bonaiuto M. Users' views of hospital environmental quality: Validation of the perceived hospital environment quality indicators (PHEQIs). Journal of Environmental Psychology. 2012;**32**(2):97-111

[66] De Giuli V, Zecchin R, Salmaso L, Corain L, De Carli M. Measured and perceived indoor environmental quality: Padua Hospital case study. Building and Environment. 2013;**59**:211-226

[67] Choi S. The relationships among indoor environmental quality, occupant satisfaction, work performance, and sustainability ethic in sustainable buildings [PhD thesis]. The University of Minnesota; 2011

[68] Hwang T, Kim JT. Assessment of indoor environmental quality in open-plan offices. Indoor and Built Environment. 2013;**22**(1):139-156

[69] Ravindu S, Rameezdeen R, Zuo J, Zhou Z, Chandratilake R. Indoor environment quality of green buildings: Case study of an LEED platinum certified factory in a warm humid tropical climate. Building and Environment. 2015;**84**:105-113

**15**

**Chapter 2**

**Abstract**

*Joseph Laquatra*

places where people live.

**1. Introduction**

Indoor Air Quality

Indoor air pollution is an international health concern because people spend a majority of their time indoors. Children are at a higher risk of health problems from pollutant exposure, especially because air in the child breathing zone is more polluted than it is in the adult breathing zone. Pollutants of concern include biological contaminants, combustion pollutants, volatile organic compounds, and radon and other soil gases. Humans have a history with lead and asbestos that goes back thousands of years to the ancient Romans and Egyptians. These two pollutants are still problems in older homes and apartments. All of these toxicants can be minimized or abated. Awareness of these issues is a critical first step in improving air quality in

**Keywords:** biological contaminants, combustion pollutants, volatile organic

In recent years, indoor air pollution has become an international health concern. Research has shown that people spend about 90% of their time indoors [1] and 75% of their time indoors in their homes [2]. Some people such as children, the elderly, and infirm spend most or all of their time indoors [3, 4]. Research also indicates that pollutant levels can be higher indoors than outdoors [5]. Concerns about indoor air quality have led to indoor air management becoming a new consumer skill. Steps involved in indoor air management include identifying a pollutant of concern, controlling it at its source, and if that fails, mitigation. Residential indoor air pollutants include biological contaminants, volatile organic compounds, radon and other soil

Biological contaminants include mold, viruses, bacteria, pollen, animal dander, and dust mites. Moisture plays an essential role in the presence of biological contaminants. As shown in **Figure 1**, warm air holds more water vapor than cold air. The cube on the left represents a volume of air that is at 75°F, with 30% relative humidity. This means that it is holding 30% of the moisture that it is *capable* of holding. When that same amount of air cools to 40°F, it contains the *same amount* of water, but it is now at 100% relative humidity. In other words, it is holding all of the moisture that it *can* hold. Moisture will condense at 100% relative humidity. This is

compounds, radon, lead, asbestos, child breathing zone

gases, combustion pollutants, lead, and asbestos.

also called the saturation point or the dew point temperature.

**2. Biological contaminants**

## **Chapter 2** Indoor Air Quality

*Joseph Laquatra*

### **Abstract**

Indoor air pollution is an international health concern because people spend a majority of their time indoors. Children are at a higher risk of health problems from pollutant exposure, especially because air in the child breathing zone is more polluted than it is in the adult breathing zone. Pollutants of concern include biological contaminants, combustion pollutants, volatile organic compounds, and radon and other soil gases. Humans have a history with lead and asbestos that goes back thousands of years to the ancient Romans and Egyptians. These two pollutants are still problems in older homes and apartments. All of these toxicants can be minimized or abated. Awareness of these issues is a critical first step in improving air quality in places where people live.

**Keywords:** biological contaminants, combustion pollutants, volatile organic compounds, radon, lead, asbestos, child breathing zone

### **1. Introduction**

In recent years, indoor air pollution has become an international health concern. Research has shown that people spend about 90% of their time indoors [1] and 75% of their time indoors in their homes [2]. Some people such as children, the elderly, and infirm spend most or all of their time indoors [3, 4]. Research also indicates that pollutant levels can be higher indoors than outdoors [5]. Concerns about indoor air quality have led to indoor air management becoming a new consumer skill. Steps involved in indoor air management include identifying a pollutant of concern, controlling it at its source, and if that fails, mitigation. Residential indoor air pollutants include biological contaminants, volatile organic compounds, radon and other soil gases, combustion pollutants, lead, and asbestos.

### **2. Biological contaminants**

Biological contaminants include mold, viruses, bacteria, pollen, animal dander, and dust mites. Moisture plays an essential role in the presence of biological contaminants. As shown in **Figure 1**, warm air holds more water vapor than cold air. The cube on the left represents a volume of air that is at 75°F, with 30% relative humidity. This means that it is holding 30% of the moisture that it is *capable* of holding. When that same amount of air cools to 40°F, it contains the *same amount* of water, but it is now at 100% relative humidity. In other words, it is holding all of the moisture that it *can* hold. Moisture will condense at 100% relative humidity. This is also called the saturation point or the dew point temperature.

#### **Figure 1.** *Warm air holds more moisture than cold air.*

When warm, moist air comes in contact with a cold surface, the water vapor in that air condenses to liquid water. In the case of a cold window, when warmer, humid air moves closer to the window, its temperature drops, and therefore its moisture-holding capability also drops. When this air touches the window, it condenses. The same thing happens on a warm and humid summer day, when warm, humid air condenses on cold beverage bottles, cans, or glasses. Sometimes, condensation on a window can be a nuisance. Other times, it can be serious enough that moisture will accumulate on the sash and on the sill, causing mold growth, warping that will damage the airtight seal between panes of glass, and even rotting. Mold spores are ubiquitous, and when a spore lands on a surface at the right temperature, with a food source—in this case, cellulose—and moisture, mold will grow.

Mold is a fungus; and as fungi grow, they release large numbers of spores into the air. And as mold digests cellulosic products, such as wood, as food, it releases carbon dioxide, water, and microbiological volatile organic compounds (mVOCs) into the air. Airborne spores affect asthmatics and people with allergies by acting as asthma triggers and the cause of respiratory illness. Microbiological volatile organic compounds are responsible for the musty smell associated with mold growth. Inhalation of mVOCs by humans can cause mycotoxicosis, symptoms of which include difficulty breathing, sore throat, bloody nose, and skin rashes.

Preventing health problems caused by exposure to mold is done by controlling moisture in homes. This means maintaining relative humidity at levels that do not allow for moisture condensation on windows and other surfaces, regularly inspecting plumbing pipes and fixtures for leaks, and preventing the entry of water from outside the home by maintaining roofs and siding and having a water-managed foundation.

Another biological contaminant commonly found in homes is the house dust mite, which feeds on skin cells that are naturally shed from human bodies. Fecal pellets from this microscopic arachnid contain a protein that is an allergen and asthma trigger. Dust mites thrive in humid environments and live in upholstered furniture, bedding, carpeting, and stuffed animals. They cannot survive at relative humidity levels below 50% [6]. Other biological contaminants in indoor air include viruses, bacteria, pollen, and animal dander. All of these can be controlled through regular house cleaning.

### **2.1 Ventilation**

A number of factors contribute to the high levels of energy efficiency that are now possible in new and existing homes. Airtightening measures—those that

**17**

**Figure 2.** *The stack effect.*

*Indoor Air Quality*

*DOI: http://dx.doi.org/10.5772/intechopen.81192*

moisture and other indoor air pollutants.

pull air out of a house but also provide make-up air.

prevent air infiltration through the building shell—are among the most critical of these. In new construction and in the improvement of an existing home, low air infiltration rates are achieved through an attention to the details of both construction materials and practices. And as air leakage has decreased in homes, ventilation has become a residential design issue because of problems that arise from excess

Before airtightening measures were as widespread as they now are, ventilation of homes was achieved naturally, as air leaked in and out of cracks in the building shell—around windows and doors, where dissimilar building materials meet, and other places. Natural ventilation is undesirable because it can never be controlled. Its rate depends on wind speed, vegetation around a house, site topography, and other variables. And natural ventilation imposes large energy costs on a home because the incoming infiltration air must be heated in the winter in cold climates. But in the absence of natural ventilation, mechanical ventilation is necessary for removing moisture and other pollutants as well as bringing fresh air into a home. A basic mechanical ventilation system consists of exhaust fans, which are ducted

to the outdoors, in kitchens and bathrooms. Conventional clothes dryers should always be ducted to the outdoors, although some electric clothes dryers vent into the washer. And some clothes washers also act as dryers. An issue that arises in airtight homes is the provision of make-up air for exhaust systems. As exhaust fans pull air out of a house, that air must be replaced. In a leaky house, that air is supplied through infiltration. This happens because the fans place negative pressure on a house and, if no windows are open, pull in air from cracks that exist in the building enclosure or from a chimney, which can be dangerous if the chimney is connected to an operating combustion appliance. Other ventilation systems exist that not only

**Figure 2** shows temperature-difference-driven infiltration, also called the stack effect. In simpler terms: a house comes under negative pressure as warm air naturally rises to upper levels of a house. That warm air escapes through various faults in the building enclosure, including cracks that form at junctions of different types of construction materials, such as those where brick meets wood siding. Warm air

#### *Indoor Air Quality DOI: http://dx.doi.org/10.5772/intechopen.81192*

*Indoor Environmental Quality*

**Figure 1.**

*Warm air holds more moisture than cold air.*

When warm, moist air comes in contact with a cold surface, the water vapor in that air condenses to liquid water. In the case of a cold window, when warmer, humid air moves closer to the window, its temperature drops, and therefore its moisture-holding capability also drops. When this air touches the window, it condenses. The same thing happens on a warm and humid summer day, when warm, humid air condenses on cold beverage bottles, cans, or glasses. Sometimes, condensation on a window can be a nuisance. Other times, it can be serious enough that moisture will accumulate on the sash and on the sill, causing mold growth, warping that will damage the airtight seal between panes of glass, and even rotting. Mold spores are ubiquitous, and when a spore lands on a surface at the right temperature,

with a food source—in this case, cellulose—and moisture, mold will grow.

include difficulty breathing, sore throat, bloody nose, and skin rashes.

Mold is a fungus; and as fungi grow, they release large numbers of spores into the air. And as mold digests cellulosic products, such as wood, as food, it releases carbon dioxide, water, and microbiological volatile organic compounds (mVOCs) into the air. Airborne spores affect asthmatics and people with allergies by acting as asthma triggers and the cause of respiratory illness. Microbiological volatile organic compounds are responsible for the musty smell associated with mold growth. Inhalation of mVOCs by humans can cause mycotoxicosis, symptoms of which

Preventing health problems caused by exposure to mold is done by controlling moisture in homes. This means maintaining relative humidity at levels that do not allow for moisture condensation on windows and other surfaces, regularly inspecting plumbing pipes and fixtures for leaks, and preventing the entry of water from outside the home by maintaining roofs and siding and having a water-managed foundation. Another biological contaminant commonly found in homes is the house dust mite, which feeds on skin cells that are naturally shed from human bodies. Fecal pellets from this microscopic arachnid contain a protein that is an allergen and asthma trigger. Dust mites thrive in humid environments and live in upholstered furniture, bedding, carpeting, and stuffed animals. They cannot survive at relative humidity levels below 50% [6]. Other biological contaminants in indoor air include viruses, bacteria, pollen, and animal dander. All of these can be controlled through regular house cleaning.

A number of factors contribute to the high levels of energy efficiency that are now possible in new and existing homes. Airtightening measures—those that

**16**

**2.1 Ventilation**

prevent air infiltration through the building shell—are among the most critical of these. In new construction and in the improvement of an existing home, low air infiltration rates are achieved through an attention to the details of both construction materials and practices. And as air leakage has decreased in homes, ventilation has become a residential design issue because of problems that arise from excess moisture and other indoor air pollutants.

Before airtightening measures were as widespread as they now are, ventilation of homes was achieved naturally, as air leaked in and out of cracks in the building shell—around windows and doors, where dissimilar building materials meet, and other places. Natural ventilation is undesirable because it can never be controlled. Its rate depends on wind speed, vegetation around a house, site topography, and other variables. And natural ventilation imposes large energy costs on a home because the incoming infiltration air must be heated in the winter in cold climates. But in the absence of natural ventilation, mechanical ventilation is necessary for removing moisture and other pollutants as well as bringing fresh air into a home.

A basic mechanical ventilation system consists of exhaust fans, which are ducted to the outdoors, in kitchens and bathrooms. Conventional clothes dryers should always be ducted to the outdoors, although some electric clothes dryers vent into the washer. And some clothes washers also act as dryers. An issue that arises in airtight homes is the provision of make-up air for exhaust systems. As exhaust fans pull air out of a house, that air must be replaced. In a leaky house, that air is supplied through infiltration. This happens because the fans place negative pressure on a house and, if no windows are open, pull in air from cracks that exist in the building enclosure or from a chimney, which can be dangerous if the chimney is connected to an operating combustion appliance. Other ventilation systems exist that not only pull air out of a house but also provide make-up air.

**Figure 2** shows temperature-difference-driven infiltration, also called the stack effect. In simpler terms: a house comes under negative pressure as warm air naturally rises to upper levels of a house. That warm air escapes through various faults in the building enclosure, including cracks that form at junctions of different types of construction materials, such as those where brick meets wood siding. Warm air

**Figure 2.** *The stack effect.*

#### *Indoor Environmental Quality*

also escapes from unsealed cracks around windows and doors. All air that leaves a house in this manner must be replenished. This happens when air leaving the house creates suction pressure on lower house levels, which causes soil gases, including radon, to be pulled into the house.

**Figure 3** shows how combustion appliances can also bring a house under negative pressure. All combustion appliances use some type of fuel, whether it is fuel oil, natural gas, propane, or wood. Oxygen is needed to fuel the fire, and if that oxygen comes from indoor air, it will put negative pressure on a house, just like the stack effect does. Air gets drawn into the appliance, fuels the fire, and that air needs to be replaced. The replaced air comes in through cracks in the building enclosure as well as cracks in the foundation of the basement, which can allow soil gases to enter the home.

A solution to negative pressure caused by a combustion appliance is to use a sealed combustion appliance. This type of furnace or boiler brings air to the combustion chamber through a pipe that originates outside the house. Sealed systems typically have a second heat exchanger that extracts heat from combustion gases that would normally be exhausted by the chimney in a conventional system. Instead, extracting additional heat from combustion gases results in exhaust gases that are cool enough to be exhausted from the house through a pipe through an exterior wall, much like a clothes dryer vent. Because the combustion air comes from outside the house, the building does not come under negative pressure.

Approaches to residential ventilation can be categorized as exhaust, supply, and balanced systems. Fans that pull air out of a space such as a bathroom exhaust fan or a kitchen range ventilation hood comprise basic exhaust ventilation systems that most people are familiar with. As noted above, however, these fans can place an airtight house under negative pressure.

Variations of exhaust systems provide make-up air to the house in some manner. The simplest way to do this is to install passive vents, which are small, screened openings in exterior walls. These admit air by opening when the home comes under negative pressure, such as when an exhaust fan is turned on. Passive vents are only recommended for use in very small, airtight homes in which depressurization is safe. Home depressurization is safe if all combustion appliances receive combustion air from outside the home; there are no fireplaces in the home; the home has no attached garage; and the home is not located in a high radon area.

More commonly used than exhaust fans with passive vents is a central exhaust system that pulls air out of a house combined with a fan that pulls fresh air into the house and delivers it through ducts to individual rooms, usually each bedroom

**19**

*Indoor Air Quality*

delivered to the rooms.

*Heat recovery ventilator.*

**Figure 4.**

problems.

**3. Volatile organic compounds**

*DOI: http://dx.doi.org/10.5772/intechopen.81192*

and living area. Whole-house fans are effective in this type of supply system. A variation of this system, if the house has a forced air furnace, is to deliver outdoor air to the return duct, so that it can be mixed with indoor air and heated before it is

A heat recovery ventilator (HRV)—also referred to as an air-to-air heat exchanger—is a balanced system that consists of a device which pulls fresh air into a home at the same time that it is exhausting air out of the home. As seen in **Figure 4**, the two airstreams are separated but pass over a core of conductive plates or heat exchanger that transfers heat from the warmer airstream to the colder one. A heat recovery ventilator also dehumidifies the home, because the warmer airstream contains moisture that condenses during the exchange process. The resulting water is delivered to a drain through a tube. HRVs can be stand-alone units with ducts or they can be integrated with the ducts of a forced air furnace. In addition to the basic systems described above, other variations exist, including central exhaust/supply systems with dehumidification and systems with air filtration options. Several studies have analyzed the cost effectiveness of various ventilation systems by examining purchase and installation costs, annual operating costs, and additional imposed heating costs (to heat incoming air). In addition to costs, benefits that are difficult to quantify include increased human comfort and the prevention of moisture

Taylor et al. [7] examined the cost-effectiveness of heat recovery ventilators and concluded that these units provide positive life-cycle cost savings throughout much

The International Residential Code (IRC) specifies mechanical ventilation standards for new homes, which vary depending on the size of the house, number of bedrooms, and tested air infiltration rate [8]. The infiltration rate is measured with a blower door test, a specialized piece of equipment that measures a home's air change per hour (ACH). ACH measures the extent to which outdoor air leaks into homes through cracks around windows, doors, and where dissimilar building materials meet. An airtight home has a low ACH; a leaky, drafty home has a high ACH.

Volatile organic compounds (VOCs) are gases released from some solids or liquids at room temperature. Many VOCs found in household air have adverse health impacts, including eye, nose, and throat irritation; asthma exacerbation; lung, kidney, and central nervous system damage; and cancer [9]. VOC sources include building products, paints, strippers, solvents, wood preservatives, air fresheners,

of the United States, although not in the colder, northern tier states.

hobby supplies, pesticides, dry-cleaned clothing, and more.

**Figure 3.** *Combustion air concepts.*

**Figure 4.** *Heat recovery ventilator.*

*Indoor Environmental Quality*

radon, to be pulled into the house.

also escapes from unsealed cracks around windows and doors. All air that leaves a house in this manner must be replenished. This happens when air leaving the house creates suction pressure on lower house levels, which causes soil gases, including

foundation of the basement, which can allow soil gases to enter the home.

house, the building does not come under negative pressure.

airtight house under negative pressure.

A solution to negative pressure caused by a combustion appliance is to use a sealed combustion appliance. This type of furnace or boiler brings air to the combustion chamber through a pipe that originates outside the house. Sealed systems typically have a second heat exchanger that extracts heat from combustion gases that would normally be exhausted by the chimney in a conventional system. Instead, extracting additional heat from combustion gases results in exhaust gases that are cool enough to be exhausted from the house through a pipe through an exterior wall, much like a clothes dryer vent. Because the combustion air comes from outside the

Approaches to residential ventilation can be categorized as exhaust, supply, and balanced systems. Fans that pull air out of a space such as a bathroom exhaust fan or a kitchen range ventilation hood comprise basic exhaust ventilation systems that most people are familiar with. As noted above, however, these fans can place an

Variations of exhaust systems provide make-up air to the house in some manner.

More commonly used than exhaust fans with passive vents is a central exhaust system that pulls air out of a house combined with a fan that pulls fresh air into the house and delivers it through ducts to individual rooms, usually each bedroom

The simplest way to do this is to install passive vents, which are small, screened openings in exterior walls. These admit air by opening when the home comes under negative pressure, such as when an exhaust fan is turned on. Passive vents are only recommended for use in very small, airtight homes in which depressurization is safe. Home depressurization is safe if all combustion appliances receive combustion air from outside the home; there are no fireplaces in the home; the home has no

attached garage; and the home is not located in a high radon area.

**Figure 3** shows how combustion appliances can also bring a house under negative pressure. All combustion appliances use some type of fuel, whether it is fuel oil, natural gas, propane, or wood. Oxygen is needed to fuel the fire, and if that oxygen comes from indoor air, it will put negative pressure on a house, just like the stack effect does. Air gets drawn into the appliance, fuels the fire, and that air needs to be replaced. The replaced air comes in through cracks in the building enclosure as well as cracks in the

**18**

**Figure 3.**

*Combustion air concepts.*

and living area. Whole-house fans are effective in this type of supply system. A variation of this system, if the house has a forced air furnace, is to deliver outdoor air to the return duct, so that it can be mixed with indoor air and heated before it is delivered to the rooms.

A heat recovery ventilator (HRV)—also referred to as an air-to-air heat exchanger—is a balanced system that consists of a device which pulls fresh air into a home at the same time that it is exhausting air out of the home. As seen in **Figure 4**, the two airstreams are separated but pass over a core of conductive plates or heat exchanger that transfers heat from the warmer airstream to the colder one. A heat recovery ventilator also dehumidifies the home, because the warmer airstream contains moisture that condenses during the exchange process. The resulting water is delivered to a drain through a tube. HRVs can be stand-alone units with ducts or they can be integrated with the ducts of a forced air furnace. In addition to the basic systems described above, other variations exist, including central exhaust/supply systems with dehumidification and systems with air filtration options. Several studies have analyzed the cost effectiveness of various ventilation systems by examining purchase and installation costs, annual operating costs, and additional imposed heating costs (to heat incoming air). In addition to costs, benefits that are difficult to quantify include increased human comfort and the prevention of moisture problems.

Taylor et al. [7] examined the cost-effectiveness of heat recovery ventilators and concluded that these units provide positive life-cycle cost savings throughout much of the United States, although not in the colder, northern tier states.

The International Residential Code (IRC) specifies mechanical ventilation standards for new homes, which vary depending on the size of the house, number of bedrooms, and tested air infiltration rate [8]. The infiltration rate is measured with a blower door test, a specialized piece of equipment that measures a home's air change per hour (ACH). ACH measures the extent to which outdoor air leaks into homes through cracks around windows, doors, and where dissimilar building materials meet. An airtight home has a low ACH; a leaky, drafty home has a high ACH.

### **3. Volatile organic compounds**

Volatile organic compounds (VOCs) are gases released from some solids or liquids at room temperature. Many VOCs found in household air have adverse health impacts, including eye, nose, and throat irritation; asthma exacerbation; lung, kidney, and central nervous system damage; and cancer [9]. VOC sources include building products, paints, strippers, solvents, wood preservatives, air fresheners, hobby supplies, pesticides, dry-cleaned clothing, and more.

The World Health Organization (WHO) categorizes VOCs by the ease with which they are emitted from materials and uses the terms very volatile organic compounds (VVOC), volatile organic compounds (VOCs), and semivolatile organic compounds (SVOCs) [10]. As mentioned earlier, VOCs produced by mold are referred to as microbiologic volatile organic compounds (mVOCs). But all of these fall into the broad category of VOCs.

Formaldehyde, a colorless, strong-smelling gas, is a common VOC used in the production of building materials, cabinets, furnishings, household cleaners, paints, landscape materials, and other products. It is used in the production of plywood, particle board, and medium density fiberboard. Formaldehyde is released into the air in a process referred to as off-gassing. Formaldehyde is also a component of cigarette smoke and a combustion product of wood, kerosene, natural gas, oil, and gasoline.

Adverse health effects from formaldehyde exposure include eye, nose, and throat irritation; wheezing and coughing; and allergic reactions. Long-term exposure to high levels of formaldehyde can cause cancer in humans.

Other VOCs of concern in indoor air include benzene, styrene, xylene, and methylene chloride. Benzene is a human carcinogen that is present in environmental tobacco smoke, solvents, plywood, particle board, fiberglass, wood paneling, adhesives, paint, caulking, and wood strippers. Styrene is used in the manufacturing of plastics, rubber, food containers, carpet backing, vinyl flooring, and resins. Acute health effects from styrene exposure include mucous membrane irritation; depression; muscle weakness; and eye, nose, and throat irritation. Chronic effects include hearing loss, peripheral neuropathy, and kidney damage. Xylene is a solvent and is a component of rubber and adhesives. Health effects from exposure include depression of the central nervous system, dizziness, irritability, and vomiting. Methylene chloride, which is also known as dichloromethane, is used in paint, paint strippers, and adhesives. Exposure can cause damage to the central nervous system, liver cancer, and lung cancer. This is not an exhaustive list of VOCs found in homes but is meant to illustrate potential hazards from common materials.

#### **3.1 VOCs and safety**

When using any product that contains VOCs, provide adequate ventilation to the work area, meet or exceed any label precautions, buy in quantities that will be consumed quickly, and dispose of containers safely. Do not allow children or pets to become exposed to these products. Low-VOC- and No-VOC-containing products are becoming widely available. When possible, use these products instead of conventional alternatives.

### **4. Radon**

Radon is a radioactive gas that has no odor, taste, or color. It is produced during the decay of uranium, has a half-life of 3.8 days, and emits alpha and gamma radiation [11]. Uranium exists in soils all over the world. The radioactive decay process causes uranium to decay to uranium. Uranium and radium are solid elements. But radium decays to a gas: radon. Radon moves easily through permeable soils, such as gravelly and sandy soils, than it does through impermeable soils, such as clay [12]. Cracks in a house foundation and other openings, such as those around pipes that penetrate a house foundation, serve as radon pathways into the house. Radon continues in the decay process once it is inside a home. Radon's decay products are lead, polonium, and bismuth. These decay products become attached to microscopic particulates in house air, which are inhaled by people in the house and lead to lung cancer.

**21**

**Figure 5.**

*Radon entering a home.*

*Indoor Air Quality*

used instead.

*DOI: http://dx.doi.org/10.5772/intechopen.81192*

a better result of a home's radon level.

The process through which radon enters a home is displayed in **Figure 5**. Radon is the second-leading cause of lung cancer after cigarette smoking; radon exposure is responsible for 21,000 deaths per year in the USA [13]. Between one and seven percent of lung cancer fatalities in the USA have been attributed to radon exposure [13]. Radon's presence can be confirmed through the use of short- or long-term radon detectors. A short-term detector consists of activated carbon, which adsorbs (collects on the surface of carbon granules) radon, is inexpensive and simple to use. Once activated, it is placed in the lowest room of the house and kept in place for three days. The house should be tested under closed house conditions. This means all windows are closed for the duration of the test, and doors are used only for normal entrances and exits. After the test period, the detector is sent to a laboratory for analysis. The laboratory then reports the test results to the sender. Radon levels in a house vary over time because of changes in weather and atmospheric pressure. So, a short-term test is effectively a snapshot of radon levels at a particular time. A long-term radon test uses what is known as an alpha track detector. This is placed in a home's living room and stays there for 90 days to a year. This type of test provides

The U. S. Environmental Protection Agency (EPA) recommends that mitigation systems be installed at or above the Action Level of 4 picocuries per liter (pCi/L) of air [14]. A mitigation system for an existing home consists of a PVC pipe that is installed through the floor of the lowest level of a home, often a basement, into a layer of gravel. That pipe is carried up through the house attic and through the roof. This pipe can also be installed on a house exterior wall. Often, an inline exhaust fan is connected to the PVC pipe and is used to pull soil gas from below the house. When that fan is used, the mitigation system is referred to as an active system. An inline fan is not always necessary and a passive mitigation system is

The EPA has developed a U.S. map that designates counties into zones. In EPA-designated Zone 1 counties, indoor radon levels are expected to be 4 pCi/L or higher; houses in Zone 2 counties are expected to have radon levels between 2 and 4 pCi/L; homes in Zone 3 counties are expected to have radon levels below 2 pCi/L.

#### *Indoor Air Quality DOI: http://dx.doi.org/10.5772/intechopen.81192*

*Indoor Environmental Quality*

**3.1 VOCs and safety**

conventional alternatives.

**4. Radon**

fall into the broad category of VOCs.

The World Health Organization (WHO) categorizes VOCs by the ease with which they are emitted from materials and uses the terms very volatile organic compounds (VVOC), volatile organic compounds (VOCs), and semivolatile organic compounds (SVOCs) [10]. As mentioned earlier, VOCs produced by mold are referred to as microbiologic volatile organic compounds (mVOCs). But all of these

Formaldehyde, a colorless, strong-smelling gas, is a common VOC used in the production of building materials, cabinets, furnishings, household cleaners, paints, landscape materials, and other products. It is used in the production of plywood, particle board, and medium density fiberboard. Formaldehyde is released into the air in a process referred to as off-gassing. Formaldehyde is also a component of cigarette smoke and a combustion product of wood, kerosene, natural gas, oil, and gasoline. Adverse health effects from formaldehyde exposure include eye, nose, and throat irritation; wheezing and coughing; and allergic reactions. Long-term expo-

Other VOCs of concern in indoor air include benzene, styrene, xylene, and methylene chloride. Benzene is a human carcinogen that is present in environmental tobacco smoke, solvents, plywood, particle board, fiberglass, wood paneling, adhesives, paint, caulking, and wood strippers. Styrene is used in the manufacturing of plastics, rubber, food containers, carpet backing, vinyl flooring, and resins. Acute health effects from styrene exposure include mucous membrane irritation; depression; muscle weakness; and eye, nose, and throat irritation. Chronic effects include hearing loss, peripheral neuropathy, and kidney damage. Xylene is a solvent and is a component of rubber and adhesives. Health effects from exposure include depression of the central nervous system, dizziness, irritability, and vomiting. Methylene chloride, which is also known as dichloromethane, is used in paint, paint strippers, and adhesives. Exposure can cause damage to the central nervous system, liver cancer, and lung cancer. This is not an exhaustive list of VOCs found in homes

sure to high levels of formaldehyde can cause cancer in humans.

but is meant to illustrate potential hazards from common materials.

air, which are inhaled by people in the house and lead to lung cancer.

When using any product that contains VOCs, provide adequate ventilation to the work area, meet or exceed any label precautions, buy in quantities that will be consumed quickly, and dispose of containers safely. Do not allow children or pets to become exposed to these products. Low-VOC- and No-VOC-containing products are becoming widely available. When possible, use these products instead of

Radon is a radioactive gas that has no odor, taste, or color. It is produced during the decay of uranium, has a half-life of 3.8 days, and emits alpha and gamma radiation [11]. Uranium exists in soils all over the world. The radioactive decay process causes uranium to decay to uranium. Uranium and radium are solid elements. But radium decays to a gas: radon. Radon moves easily through permeable soils, such as gravelly and sandy soils, than it does through impermeable soils, such as clay [12]. Cracks in a house foundation and other openings, such as those around pipes that penetrate a house foundation, serve as radon pathways into the house. Radon continues in the decay process once it is inside a home. Radon's decay products are lead, polonium, and bismuth. These decay products become attached to microscopic particulates in house

**20**

The process through which radon enters a home is displayed in **Figure 5**. Radon is the second-leading cause of lung cancer after cigarette smoking; radon exposure is responsible for 21,000 deaths per year in the USA [13]. Between one and seven percent of lung cancer fatalities in the USA have been attributed to radon exposure [13].

Radon's presence can be confirmed through the use of short- or long-term radon detectors. A short-term detector consists of activated carbon, which adsorbs (collects on the surface of carbon granules) radon, is inexpensive and simple to use. Once activated, it is placed in the lowest room of the house and kept in place for three days. The house should be tested under closed house conditions. This means all windows are closed for the duration of the test, and doors are used only for normal entrances and exits. After the test period, the detector is sent to a laboratory for analysis. The laboratory then reports the test results to the sender. Radon levels in a house vary over time because of changes in weather and atmospheric pressure. So, a short-term test is effectively a snapshot of radon levels at a particular time. A long-term radon test uses what is known as an alpha track detector. This is placed in a home's living room and stays there for 90 days to a year. This type of test provides a better result of a home's radon level.

The U. S. Environmental Protection Agency (EPA) recommends that mitigation systems be installed at or above the Action Level of 4 picocuries per liter (pCi/L) of air [14]. A mitigation system for an existing home consists of a PVC pipe that is installed through the floor of the lowest level of a home, often a basement, into a layer of gravel. That pipe is carried up through the house attic and through the roof. This pipe can also be installed on a house exterior wall. Often, an inline exhaust fan is connected to the PVC pipe and is used to pull soil gas from below the house. When that fan is used, the mitigation system is referred to as an active system. An inline fan is not always necessary and a passive mitigation system is used instead.

The EPA has developed a U.S. map that designates counties into zones. In EPA-designated Zone 1 counties, indoor radon levels are expected to be 4 pCi/L or higher; houses in Zone 2 counties are expected to have radon levels between 2 and 4 pCi/L; homes in Zone 3 counties are expected to have radon levels below 2 pCi/L.

**Figure 5.** *Radon entering a home.*

**Figure 6.** *EPA Radon Zone Map.*

**Figure 6** shows the EPA Radon Map. Zone 1 counties are red; Zone 2 counties are orange; and Zone 3 counties are yellow.

Radon-resistant construction techniques are recommended for new homes built in Zone 1 counties [15].

### **5. Combustion products**

Combustion products comprise another category of indoor air pollutants. They consist of nitrogen oxides, sulfur dioxide, carbon monoxide, respirable particulates, and water. Nitrogen oxides, sulfur dioxides, and respirable particulates are lung irritants, and carbon monoxide (CO) can kill. To avoid indoor these pollutants, combustion-based, unvented space heaters should not be in the home. Central heating system systems should be regularly serviced: annual servicing for fuel oil-based systems and every 2 years for gas systems. Smoking should not be permitted in a home, and a gas kitchen range should have an exhaust fan over it that is vented to the outside.

Combustion products can pollute the air inside a home when components of a central heating system are damaged and leak combustion gases into indoor air. Indoor use of combustion-based electric generators will also do this. And when a house comes under negative pressure, combustion gases can be drawn from a chimney or fireplace into the home.

Normally, when a person breathes healthy air, oxygen binds with hemoglobin in blood to form oxyhemoglobin. When a person breathes air that is polluted with CO, CO binds with hemoglobin, and carboxyhemoglobin is formed, which prevents oxygen from getting to the brain. At low levels, this causes tiredness and dizziness. At higher levels, gradual suffocation and death occur. Carbon monoxide is responsible for hundreds of deaths and thousands of emergency room visits in the USA per year [16]. These are all preventable deaths and often occur when people are sleeping. Every home and apartment should have at least one carbon monoxide

**23**

issue.

**7. Asbestos**

*Indoor Air Quality*

home.

**6. Lead**

*DOI: http://dx.doi.org/10.5772/intechopen.81192*

the USA with lead-based paint [18].

effects. No level of exposure to lead is safe [19].

planted to discourage children from playing in that soil.

and wallets; and others [21].

ing board covers and potholders.

detector installed in the hallway outside the sleeping area. Carbon monoxide detectors are important, but they are no substitute for regular servicing of combustion appliances and common sense safety procedures with combustion appliances in the

People have used lead for numerous purposes for at least 7000 years [17]. Before 1550 BCE, ancient Egyptians used lead as a medicine and for decorative purposes. When babies were born, a lead ball was placed on their belly buttons to stop bleeding. Women would decorate their nipples with lead and breast feed their babies. People have been aware of lead poisoning for over 2000 years [17]. In spite of this, lead was not banned as an ingredient in residential paint in the USA until 1978 and in gasoline until 1986. There are an estimated 24 million homes and apartments in

Negative health impacts from lead exposure include reduced IQ levels, behavioral problems, organ damage, anemia, convulsions, and death. Children

affected as well. Pregnant women can experience damage to a fetus from lead. Exposure occurs through inhalation, ingestion, and dermatological contact. The U.S. Centers for Disease Control and Prevention (CDC) set 5 micrograms of lead per deciliter (μg/dL) of blood as a reference for public health actions, but there is no minimum level of exposure that is considered to be free of negative health

Lead-painted surfaces can produce a fine dust that is poisonous, especially to infants and children. This dust accumulates on floors under lead-painted windows and other building components. Toddlers crawl through this dust and ingest it through hand-to-mouth contact. This can also occur as children play outside in lead-contaminated soil. These hazards can be reduced or eliminated by following Lead Safe Work Practices to remove or encapsulate lead-based paint on a home's interior and exterior surfaces [20]. For soil contaminated with lead from paint chips or vehicle exhaust, that soil should be replaced, or barriers such as bushes should be

Lead is also present in many household products, including slow cookers; lipstick and other cosmetics; house keys; hair dyes; faux leather purses, sandals,

The term asbestos refers to naturally occurring silicate minerals that are heat-resistant and fibrous. The fibers are soft and can be easily incorporated into building materials. Chrysotile, or white asbestos, was most commonly used in construction materials. Asbestos is found in older homes. It was used as insulation on heating systems and heating ducts. In some older homes, it actually covers entire boilers. Asbestos was also a component of joint compound, sheet goods that were used as fire barriers behind wood-burning stoves, roof sealants, floor and ceiling tile adhesives, gaskets, and automobile brake pads. Asbestos was also used in iron-

Consumer education on this topic is necessary to inform the public about this

face higher risks of health problems from lead exposure, but adults are

detector installed in the hallway outside the sleeping area. Carbon monoxide detectors are important, but they are no substitute for regular servicing of combustion appliances and common sense safety procedures with combustion appliances in the home.

### **6. Lead**

*Indoor Environmental Quality*

orange; and Zone 3 counties are yellow.

in Zone 1 counties [15].

**Figure 6.**

*EPA Radon Zone Map.*

the outside.

**5. Combustion products**

chimney or fireplace into the home.

**Figure 6** shows the EPA Radon Map. Zone 1 counties are red; Zone 2 counties are

Radon-resistant construction techniques are recommended for new homes built

Combustion products comprise another category of indoor air pollutants. They consist of nitrogen oxides, sulfur dioxide, carbon monoxide, respirable particulates, and water. Nitrogen oxides, sulfur dioxides, and respirable particulates are lung irritants, and carbon monoxide (CO) can kill. To avoid indoor these pollutants, combustion-based, unvented space heaters should not be in the home. Central heating system systems should be regularly serviced: annual servicing for fuel oil-based systems and every 2 years for gas systems. Smoking should not be permitted in a home, and a gas kitchen range should have an exhaust fan over it that is vented to

Combustion products can pollute the air inside a home when components of a central heating system are damaged and leak combustion gases into indoor air. Indoor use of combustion-based electric generators will also do this. And when a house comes under negative pressure, combustion gases can be drawn from a

Normally, when a person breathes healthy air, oxygen binds with hemoglobin in blood to form oxyhemoglobin. When a person breathes air that is polluted with CO, CO binds with hemoglobin, and carboxyhemoglobin is formed, which prevents oxygen from getting to the brain. At low levels, this causes tiredness and dizziness. At higher levels, gradual suffocation and death occur. Carbon monoxide is responsible for hundreds of deaths and thousands of emergency room visits in the USA per year [16]. These are all preventable deaths and often occur when people are sleeping. Every home and apartment should have at least one carbon monoxide

**22**

People have used lead for numerous purposes for at least 7000 years [17]. Before 1550 BCE, ancient Egyptians used lead as a medicine and for decorative purposes. When babies were born, a lead ball was placed on their belly buttons to stop bleeding. Women would decorate their nipples with lead and breast feed their babies. People have been aware of lead poisoning for over 2000 years [17]. In spite of this, lead was not banned as an ingredient in residential paint in the USA until 1978 and in gasoline until 1986. There are an estimated 24 million homes and apartments in the USA with lead-based paint [18].

Negative health impacts from lead exposure include reduced IQ levels, behavioral problems, organ damage, anemia, convulsions, and death. Children face higher risks of health problems from lead exposure, but adults are affected as well. Pregnant women can experience damage to a fetus from lead. Exposure occurs through inhalation, ingestion, and dermatological contact. The U.S. Centers for Disease Control and Prevention (CDC) set 5 micrograms of lead per deciliter (μg/dL) of blood as a reference for public health actions, but there is no minimum level of exposure that is considered to be free of negative health effects. No level of exposure to lead is safe [19].

Lead-painted surfaces can produce a fine dust that is poisonous, especially to infants and children. This dust accumulates on floors under lead-painted windows and other building components. Toddlers crawl through this dust and ingest it through hand-to-mouth contact. This can also occur as children play outside in lead-contaminated soil. These hazards can be reduced or eliminated by following Lead Safe Work Practices to remove or encapsulate lead-based paint on a home's interior and exterior surfaces [20]. For soil contaminated with lead from paint chips or vehicle exhaust, that soil should be replaced, or barriers such as bushes should be planted to discourage children from playing in that soil.

Lead is also present in many household products, including slow cookers; lipstick and other cosmetics; house keys; hair dyes; faux leather purses, sandals, and wallets; and others [21].

Consumer education on this topic is necessary to inform the public about this issue.

### **7. Asbestos**

The term asbestos refers to naturally occurring silicate minerals that are heat-resistant and fibrous. The fibers are soft and can be easily incorporated into building materials. Chrysotile, or white asbestos, was most commonly used in construction materials. Asbestos is found in older homes. It was used as insulation on heating systems and heating ducts. In some older homes, it actually covers entire boilers. Asbestos was also a component of joint compound, sheet goods that were used as fire barriers behind wood-burning stoves, roof sealants, floor and ceiling tile adhesives, gaskets, and automobile brake pads. Asbestos was also used in ironing board covers and potholders.

Like lead, humans have used asbestos for thousands of years. In ancient Egypt, pharaohs were embalmed in asbestos cloth. Ancient Roman aristocrats used asbestos tablecloths and napkins. After these items were used, they were placed in fires to clean them. The ancient Roman philosopher, Pliny the Elder, wrote about asbestos-caused lung disease and how asbestos mining slaves suffered from lung disease and made crude respirators to protect themselves [22].

Asbestos exposure occurs when asbestos fibers become friable, or airborne, and are inhaled. These fibers are microscopic and cannot be seen. This makes it possible for someone to inhale a large amount of fibers without knowing it. The fibers become embedded deep within the lungs, and the body cannot expel them. Exposure causes asbestosis, a type of lung cancer, and mesothelioma, which is a cancer of the mesothelial lining of the lungs. These diseases begin to show symptoms 10–40 years after initial exposure to asbestos.

Asbestos abatement is not a do-it-yourself activity. Its removal and encapsulation are regulated in the USA and must be performed by certified abatement contractors. These contractors seal off the work area where asbestos will be removed and wear disposable full-body protective suits and full head protection with respirators.

### **8. The child breathing zone**

Children face higher risks than adults do from being exposed to environmental toxicants and from health problems caused by such exposure [23]. This is because children breathe larger amounts of air per body size when compared to adults. Sucking on hands and toys that have accumulated pollutants adds to these risks [24]. Another source of VOC exposure to infants is those that are emitted from crib mattresses and crib mattress covers [25].

The fact that 80% of children's alveoli are formed postnatally, and changes in the lung continue through adolescence, make children more vulnerable to developing health problems from air pollutants [26]. During the early postneonatal period, developing lungs are very susceptible to pollutants; and the immature immune, pulmonary, and nervous systems of children can be damaged by environmental pollutants, including routinely applied residential pesticides.

Young and older infants and young children breathe through their mouths than adults do. This difference in breathing patterns is likely to increase a child's risk of exposure to respirable particulates [27]. This risk is lower for adults whose breathing through their noses causes air to become filtered as they breathe it through the upper respiratory airway [27].

Toddlers crawl on the floor and young children walk, run, and play on the floor. These factors cause the breathing zone of children to be much lower (up to 3 feet from the floor). This zone is known as the child breathing zone (CBZ) [28]. Walking-induced turbulence in a room causes resuspension of respirable particulates, and shorter people are exposed to more resuspended particulates than taller people. IAQ can be significantly worse in the CBZ than in the adult breathing zone (ABZ), and the assumption of uniform pollutant concentration in indoor environments can be an erroneous assumption of breathing concentration risk. Although there is an increasing awareness that children are vulnerable to poor IAQ in the scientific community, there is very limited research with a focus on IAQ in the CBZ. There is no current IAQ management system that specifically focuses on improving IAQ in the CBZ.

**25**

**Author details**

Joseph Laquatra

*Indoor Air Quality*

**9. Conclusion**

*DOI: http://dx.doi.org/10.5772/intechopen.81192*

The most effective strategy for controlling indoor air pollution is to control the problem at its source. Ventilation is also important, especially in the case of moisture. Expel moisture to the outside through exhaust fans that are vented to the outdoors. In the case of combustion pollutants, regular servicing of heating systems and other appliances that are combustion based is necessary. Radon gas is a radioactive human carcinogen that is colorless, tasteless, and odorless. This pollutant can be controlled through mitigation in existing homes and with radon-resistant construction techniques in new homes. Exposure to some VOCs, which are present in building materials, paints, strippers, and other substances, can be hazardous to human health. Adequate ventilation should be provided when using these materials. Low- or no-VOC emitting products are now available and should be considered as safer alternatives. Lead and asbestos are present in older homes and apartments and pose considerable health risks to humans. Only trained professionals should perform abatement or encapsulation of both materials. Children are at a higher risk of health problems from pollutant exposure, especially because air in the child breathing zone is more polluted than it is in the adult breathing zone. Awareness of these issues is a critical first step in improving air quality in homes and apartments.

provided the original work is properly cited.

Cornell University, Ithaca, New York, USA

\*Address all correspondence to: jl27@cornell.edu

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

### **9. Conclusion**

*Indoor Environmental Quality*

protect themselves [22].

with respirators.

pesticides.

**8. The child breathing zone**

upper respiratory airway [27].

improving IAQ in the CBZ.

mattresses and crib mattress covers [25].

toms 10–40 years after initial exposure to asbestos.

Like lead, humans have used asbestos for thousands of years. In ancient Egypt, pharaohs were embalmed in asbestos cloth. Ancient Roman aristocrats used asbestos tablecloths and napkins. After these items were used, they were placed in fires to clean them. The ancient Roman philosopher, Pliny the Elder, wrote about asbestos-caused lung disease and how asbestos mining slaves suffered from lung disease and made crude respirators to

Asbestos exposure occurs when asbestos fibers become friable, or airborne, and are inhaled. These fibers are microscopic and cannot be seen. This makes it possible for someone to inhale a large amount of fibers without knowing it. The fibers become embedded deep within the lungs, and the body cannot expel them. Exposure causes asbestosis, a type of lung cancer, and mesothelioma, which is a cancer of the mesothelial lining of the lungs. These diseases begin to show symp-

Asbestos abatement is not a do-it-yourself activity. Its removal and encapsula-

Children face higher risks than adults do from being exposed to environmental toxicants and from health problems caused by such exposure [23]. This is because children breathe larger amounts of air per body size when compared to adults. Sucking on hands and toys that have accumulated pollutants adds to these risks [24]. Another source of VOC exposure to infants is those that are emitted from crib

The fact that 80% of children's alveoli are formed postnatally, and changes

Young and older infants and young children breathe through their mouths than adults do. This difference in breathing patterns is likely to increase a child's risk of exposure to respirable particulates [27]. This risk is lower for adults whose breathing through their noses causes air to become filtered as they breathe it through the

Toddlers crawl on the floor and young children walk, run, and play on the floor. These factors cause the breathing zone of children to be much lower (up to 3 feet from the floor). This zone is known as the child breathing zone (CBZ) [28]. Walking-induced turbulence in a room causes resuspension of respirable particulates, and shorter people are exposed to more resuspended particulates than taller people. IAQ can be significantly worse in the CBZ than in the adult breathing zone (ABZ), and the assumption of uniform pollutant concentration in indoor environments can be an erroneous assumption of breathing concentration risk. Although there is an increasing awareness that children are vulnerable to poor IAQ in the scientific community, there is very limited research with a focus on IAQ in the CBZ. There is no current IAQ management system that specifically focuses on

in the lung continue through adolescence, make children more vulnerable to developing health problems from air pollutants [26]. During the early postneonatal period, developing lungs are very susceptible to pollutants; and the immature immune, pulmonary, and nervous systems of children can be damaged by environmental pollutants, including routinely applied residential

tion are regulated in the USA and must be performed by certified abatement contractors. These contractors seal off the work area where asbestos will be removed and wear disposable full-body protective suits and full head protection

**24**

The most effective strategy for controlling indoor air pollution is to control the problem at its source. Ventilation is also important, especially in the case of moisture. Expel moisture to the outside through exhaust fans that are vented to the outdoors. In the case of combustion pollutants, regular servicing of heating systems and other appliances that are combustion based is necessary. Radon gas is a radioactive human carcinogen that is colorless, tasteless, and odorless. This pollutant can be controlled through mitigation in existing homes and with radon-resistant construction techniques in new homes. Exposure to some VOCs, which are present in building materials, paints, strippers, and other substances, can be hazardous to human health. Adequate ventilation should be provided when using these materials. Low- or no-VOC emitting products are now available and should be considered as safer alternatives. Lead and asbestos are present in older homes and apartments and pose considerable health risks to humans. Only trained professionals should perform abatement or encapsulation of both materials. Children are at a higher risk of health problems from pollutant exposure, especially because air in the child breathing zone is more polluted than it is in the adult breathing zone. Awareness of these issues is a critical first step in improving air quality in homes and apartments.

### **Author details**

Joseph Laquatra Cornell University, Ithaca, New York, USA

\*Address all correspondence to: jl27@cornell.edu

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Cincinelli A, Martellini T. Indoor air quality and health. International Journal of Environmental Resources and Public Health. 2017;**14**(11):1286. DOI: 10.3390/ ijerph14111286

[2] Leech JA, Smith-Doiron M. Exposure time and place: Do COPD patients differ from the general population? Journal of Exposure Science & Environmental Epidemiology. 2016;**16**(3):238-241. DOI: 10.1038/sj.jea.7500452

[3] Coelho C, Steers M, Lutzler L, Schriver-Mazzuoli. Indoor air pollution in old people's homes related to some health problems: A survey study. Indoor Air. 2005;**15**:267-274. DOI: 10.1111/j.1600-0668.2005.00371.x

[4] Franklin PJ. Indoor air quality and respiratory health of children. Paediatric Respiratory Reviews. 2007;**8**(4):281-286. DOI: 10.1016/j.prrv.2007.08.007

[5] Ponessa J. Indoor air quality. In: Carswell AT, editor. The Encyclopedia of Housing. Thousand Oaks, CA: SAGE Publications, Inc; 2012. pp. 392-396. DOI: 10.4135/9781452218380.n137

[6] Arlian LG. Water balance and humidity requirements of house dust mites. Experimental and Applied Acarology. 1992;**16**(1-2):15-35. DOI: 10.1007/BF01201490

[7] Taylor T, Mendon V, Zhao M. Cost-Effectiveness of Heat Recovery Ventilation. 2015. Available from: https://www.energycodes.gov/sites/ default/files/documents/iecc2018\_R-3\_ analysis\_final.pdf [Accessed: April 19, 2018]

[8] Tech Note: Whole-House Mechanical Ventilation Code: Safety and Performance Considerations. 2013. Available from: http://www.homeinnovation. com/~/media/Files/Reports/

TechNote\_WH\_Ventilation\_10252013. pdf [Accessed: April 19, 2018]

[9] Shin SH, Jo WK. Temporal characteristics of volatile organic compounds in newlyconstructed residential buildings. Environmental Engineering Research. 2013;**18**(3):169-176

[10] U.S. Environmental Protection Agency (EPA). Indoor Air Quality. 2017. Available from: https://www.epa. gov/indoor-air-quality-iaq/technicaloverview-volatile-organic-compounds [Accessed: April 22, 2018]

[11] Porta M, Last JM. A Dictionary of Public Health. 2nd ed. Oxford: Oxford University Press; 2018. DOI: 10.1093/ acref/9780191844386.001.0001

[12] U.S. Geological Survey. The Geology of Radon. 1995. Available from: https://certmapper.cr.usgs.gov/data/ PubArchives/radon/georadon/3.html [Accessed: August 21, 2018]

[13] U.S. Environmental Protection Agency (EPA). Health Risk of Radon. 2018. Available from: https://www.epa. gov/radon/health-risk-radon [Accessed: April 22, 2018]

[14] U.S. Environmental Protection Agency (EPA). A Citizen's Guide to Radon. 2016. Available from: https:// www.epa.gov/sites/production/ files/2016-12/documents/2016\_a\_ citizens\_guide\_to\_radon.pdf [Accessed: September 25, 2018]

[15] U.S. Environmental Protection Agency (EPA). Radon-Resistant Construction Basics and Techniques. 2018. Available from: https://www. epa.gov/radon/radon-resistantconstruction-basics-and-techniques [Accessed: April 22, 2018]

[16] Hampson NB. U.S. mortality due to carbon monoxide poisoning, 1999-2014.

**27**

*Indoor Air Quality*

2010;**2**:92-97

May 8, 2018]

May 21, 2013]

2018]

*DOI: http://dx.doi.org/10.5772/intechopen.81192*

[23] Canha N, Mandin C, Ramalho O, Wyart G, Ribéron J, Dassonville C, et al. Assessment of ventilation and indoor air pollutants in nursery and elementary schools in France. Indoor

[24] Klepeis NE, Nelson WC, Ott WR, Robinson JP, Tsang AM, Switzer P. The National Human Activity Pattern Survey (NHAPS): A resource for assessing exposure to environmental pollutants. Journal of Exposure Analysis and Environmental Epidemiology.

[25] Boor BE, Järnström H, Novoselac A, Xu Y. Infant exposure to emissions of volatile organic compounds from crib mattresses. Environmental Science & Technology. 2014;**8**(6):3541-3549

[26] Dietert RR, Etzel RA, Chen D, Halonen M, Holladay SD, Jarabek AM, Landreth K, Peden DB, Pinkerton K, Smialowicz RJ, Zoetis T. Workshop to identify critical windows of exposure for children's health: Immune and respiratory systems work group summary. Environmental Health Perspectives. 2000;**108**(S3):483-490

[27] Flynn E, Matz P, Woolf A, Wright R. Indoor Air Pollutants Affecting Child Health. American College of Medical Toxicology. 2000. Available from : https://www.allergycosmos. co.uk/wp-content/uploads/2010/02/ IndoorAirPolution.pdf [Accessed: May

[28] Tripathii E, Laquatra J. Managing indoor air quality in the child breathing zone: Risk analysis and mitigation. Journal of Architectural Engineering. 2018;**24**(1):04018002-1-9. DOI: 10.1061/

(ASCE)AE.1943-5568.0000300

18, 2018]

Air. 2016;**26**(3):350-365

2001;**11**(3):231-252

Accidental and intentional deaths. Annals of the American Thoracic Society. 2016;**13**(10):1768-1774

[17] Chauhan AS, Bhadauria R, Singh AK, Lodhi SS, Chaturvedi DK, Tomar VS. Determination of lead and cadmium

Chemical and Pharmaceutical Research.

[18] Jacobs DE, Clickner RP, Zhou JY, Viet SM, Marker DA, Rogers JW, Zeldin DC, Broene P, Friedman W. The prevalence of lead-based paint hazards in U.S. housing. Environmental Health Perspectives. 2002;**110**:A599-A606. Available from: http://ehpnet1. niehs.nih.gov/docs/2002/110pA599- A606jacobs/abstract.html [Accessed:

[19] American Academy of Pediatrics. AAP Commends CDC for Recognizing that for Children, There is no Safe Level of Lead Exposure. 2012. Available from: https://www.aap.org/en-us/ about-the-aap/aap-press-room/Pages/ AAP-Statement-CDC-Revised-Lead-Exposure-Guidelines.aspx [Accessed:

[20] U.S. Department of Housing and Urban Development (HUD). Lead Paint Safety. A Field Guide for Painting, Home Maintenance, and Renovation Work. 2001. Available from: https:// www.hud.gov/sites/documents/ DOC\_11878.PDF [Accessed: May 8,

[21] Laquatra J. Lead in household products. In: Snedeker SM, editor. Toxicants in Plastics and Paper: Exposure and Health Risks to

Consumers from Household Products and Food Packaging, Molecular And Integrative Technology. London:

Springer-Verlag; 2014. pp. 231-243. DOI:

10.1007/978-1-4471-6500-2\_9

[22] Povtak T. What Is Asbestos? Available from: https://www.asbestos. com/asbestos/ [Accessed: May 17, 2018]

in cosmetic products. Journal of

*Indoor Air Quality DOI: http://dx.doi.org/10.5772/intechopen.81192*

Accidental and intentional deaths. Annals of the American Thoracic Society. 2016;**13**(10):1768-1774

[17] Chauhan AS, Bhadauria R, Singh AK, Lodhi SS, Chaturvedi DK, Tomar VS. Determination of lead and cadmium in cosmetic products. Journal of Chemical and Pharmaceutical Research. 2010;**2**:92-97

[18] Jacobs DE, Clickner RP, Zhou JY, Viet SM, Marker DA, Rogers JW, Zeldin DC, Broene P, Friedman W. The prevalence of lead-based paint hazards in U.S. housing. Environmental Health Perspectives. 2002;**110**:A599-A606. Available from: http://ehpnet1. niehs.nih.gov/docs/2002/110pA599- A606jacobs/abstract.html [Accessed: May 8, 2018]

[19] American Academy of Pediatrics. AAP Commends CDC for Recognizing that for Children, There is no Safe Level of Lead Exposure. 2012. Available from: https://www.aap.org/en-us/ about-the-aap/aap-press-room/Pages/ AAP-Statement-CDC-Revised-Lead-Exposure-Guidelines.aspx [Accessed: May 21, 2013]

[20] U.S. Department of Housing and Urban Development (HUD). Lead Paint Safety. A Field Guide for Painting, Home Maintenance, and Renovation Work. 2001. Available from: https:// www.hud.gov/sites/documents/ DOC\_11878.PDF [Accessed: May 8, 2018]

[21] Laquatra J. Lead in household products. In: Snedeker SM, editor. Toxicants in Plastics and Paper: Exposure and Health Risks to Consumers from Household Products and Food Packaging, Molecular And Integrative Technology. London: Springer-Verlag; 2014. pp. 231-243. DOI: 10.1007/978-1-4471-6500-2\_9

[22] Povtak T. What Is Asbestos? Available from: https://www.asbestos. com/asbestos/ [Accessed: May 17, 2018] [23] Canha N, Mandin C, Ramalho O, Wyart G, Ribéron J, Dassonville C, et al. Assessment of ventilation and indoor air pollutants in nursery and elementary schools in France. Indoor Air. 2016;**26**(3):350-365

[24] Klepeis NE, Nelson WC, Ott WR, Robinson JP, Tsang AM, Switzer P. The National Human Activity Pattern Survey (NHAPS): A resource for assessing exposure to environmental pollutants. Journal of Exposure Analysis and Environmental Epidemiology. 2001;**11**(3):231-252

[25] Boor BE, Järnström H, Novoselac A, Xu Y. Infant exposure to emissions of volatile organic compounds from crib mattresses. Environmental Science & Technology. 2014;**8**(6):3541-3549

[26] Dietert RR, Etzel RA, Chen D, Halonen M, Holladay SD, Jarabek AM, Landreth K, Peden DB, Pinkerton K, Smialowicz RJ, Zoetis T. Workshop to identify critical windows of exposure for children's health: Immune and respiratory systems work group summary. Environmental Health Perspectives. 2000;**108**(S3):483-490

[27] Flynn E, Matz P, Woolf A, Wright R. Indoor Air Pollutants Affecting Child Health. American College of Medical Toxicology. 2000. Available from : https://www.allergycosmos. co.uk/wp-content/uploads/2010/02/ IndoorAirPolution.pdf [Accessed: May 18, 2018]

[28] Tripathii E, Laquatra J. Managing indoor air quality in the child breathing zone: Risk analysis and mitigation. Journal of Architectural Engineering. 2018;**24**(1):04018002-1-9. DOI: 10.1061/ (ASCE)AE.1943-5568.0000300

**26**

2018]

*Indoor Environmental Quality*

[1] Cincinelli A, Martellini T. Indoor air quality and health. International Journal of Environmental Resources and Public Health. 2017;**14**(11):1286. DOI: 10.3390/

TechNote\_WH\_Ventilation\_10252013.

pdf [Accessed: April 19, 2018]

[9] Shin SH, Jo WK. Temporal characteristics of volatile organic compounds in newlyconstructed residential buildings. Environmental Engineering Research.

[10] U.S. Environmental Protection Agency (EPA). Indoor Air Quality. 2017. Available from: https://www.epa. gov/indoor-air-quality-iaq/technicaloverview-volatile-organic-compounds

[11] Porta M, Last JM. A Dictionary of Public Health. 2nd ed. Oxford: Oxford University Press; 2018. DOI: 10.1093/ acref/9780191844386.001.0001

[12] U.S. Geological Survey. The Geology

of Radon. 1995. Available from: https://certmapper.cr.usgs.gov/data/ PubArchives/radon/georadon/3.html

[13] U.S. Environmental Protection Agency (EPA). Health Risk of Radon. 2018. Available from: https://www.epa. gov/radon/health-risk-radon [Accessed:

[14] U.S. Environmental Protection Agency (EPA). A Citizen's Guide to Radon. 2016. Available from: https:// www.epa.gov/sites/production/ files/2016-12/documents/2016\_a\_ citizens\_guide\_to\_radon.pdf [Accessed:

[15] U.S. Environmental Protection Agency (EPA). Radon-Resistant Construction Basics and Techniques. 2018. Available from: https://www. epa.gov/radon/radon-resistantconstruction-basics-and-techniques

[16] Hampson NB. U.S. mortality due to carbon monoxide poisoning, 1999-2014.

[Accessed: August 21, 2018]

April 22, 2018]

September 25, 2018]

[Accessed: April 22, 2018]

2013;**18**(3):169-176

[Accessed: April 22, 2018]

[2] Leech JA, Smith-Doiron M. Exposure time and place: Do COPD patients differ from the general population? Journal of Exposure Science & Environmental Epidemiology. 2016;**16**(3):238-241. DOI:

**References**

ijerph14111286

10.1038/sj.jea.7500452

[3] Coelho C, Steers M, Lutzler L, Schriver-Mazzuoli. Indoor air pollution in old people's homes related to some health problems: A survey study. Indoor Air. 2005;**15**:267-274. DOI: 10.1111/j.1600-0668.2005.00371.x

[4] Franklin PJ. Indoor air quality and respiratory health of children. Paediatric Respiratory Reviews. 2007;**8**(4):281-286.

DOI: 10.1016/j.prrv.2007.08.007

[5] Ponessa J. Indoor air quality. In: Carswell AT, editor. The Encyclopedia of Housing. Thousand Oaks, CA: SAGE Publications, Inc; 2012. pp. 392-396. DOI: 10.4135/9781452218380.n137

[6] Arlian LG. Water balance and humidity requirements of house dust mites. Experimental and Applied Acarology. 1992;**16**(1-2):15-35. DOI:

[7] Taylor T, Mendon V, Zhao M. Cost-Effectiveness of Heat Recovery Ventilation. 2015. Available from: https://www.energycodes.gov/sites/ default/files/documents/iecc2018\_R-3\_ analysis\_final.pdf [Accessed: April 19,

[8] Tech Note: Whole-House Mechanical Ventilation Code: Safety and Performance Considerations. 2013. Available from: http://www.homeinnovation. com/~/media/Files/Reports/

10.1007/BF01201490

Chapter 3

Abstract

healthy buildings.

1. Introduction

29

enhanced living environments

Indoor Air Quality Monitoring for

Since most people spend 90% of their time indoors, the indoor environment has

a determining influence on human health. In many instances, the air quality parameters are very different from those defined as healthy values. Using real-time monitoring, occupants or the building manager can decide and control behaviors and interventions to improve indoor air quality. The historical database is also useful for assisting doctors to support the medical diagnosis. The continuous technological advancements notably, as regards, networking, sensors, and embedded devices have made it possible to monitor and provide assistance to people in their homes. Smart objects with great capabilities for sensing and connecting could revolutionize the way we are monitoring our environment. This chapter consists of a general overview of several real-time monitoring systems developed and published by the authors. In this chapter, the authors present several new open-source and cost-effective systems that had been developed for monitoring environmental parameters, always with the aim of improving indoor air quality for enhanced

Keywords: indoor air quality (IAQ), healthy buildings, occupational health, real-time monitoring, Internet of Things (IoT), ambient assisted living (AAL),

use, alcoholism or the problem of sexually transmitted diseases [2].

Indoor environments could be characterized by several pollutant sources. Environmental Protection Agency (EPA) is responsible for environmental air quality index regulation in the United States. This independent agency deliberates that indoor levels of contaminants can be up to 100 times greater than outdoor contaminant level and positioned poor air quality as one of the top five environmental dangers to the community well-being [1]. Thus, indoor air quality (IAQ) is recognized as an essential factor to be controlled for the occupants' health and comfort. Increase in the IAQ is critical as people typically spend more than 90% of their time in indoor environments. The problem of inadequate IAQ is of utmost importance affecting particularly severe form the poorest people in the world who are most vulnerable, presenting itself as a severe problem for world health such as tobacco

In 1983, the World Health Organization (WHO) used the term "sick building syndrome" (SBS) to the clinical features that we might discover in building residents as a consequence of the poor IAQ [3]. Numerous statements have reported the

Enhanced Healthy Buildings

Gonçalo Marques and Rui Pitarma

### Chapter 3

## Indoor Air Quality Monitoring for Enhanced Healthy Buildings

Gonçalo Marques and Rui Pitarma

### Abstract

Since most people spend 90% of their time indoors, the indoor environment has a determining influence on human health. In many instances, the air quality parameters are very different from those defined as healthy values. Using real-time monitoring, occupants or the building manager can decide and control behaviors and interventions to improve indoor air quality. The historical database is also useful for assisting doctors to support the medical diagnosis. The continuous technological advancements notably, as regards, networking, sensors, and embedded devices have made it possible to monitor and provide assistance to people in their homes. Smart objects with great capabilities for sensing and connecting could revolutionize the way we are monitoring our environment. This chapter consists of a general overview of several real-time monitoring systems developed and published by the authors. In this chapter, the authors present several new open-source and cost-effective systems that had been developed for monitoring environmental parameters, always with the aim of improving indoor air quality for enhanced healthy buildings.

Keywords: indoor air quality (IAQ), healthy buildings, occupational health, real-time monitoring, Internet of Things (IoT), ambient assisted living (AAL), enhanced living environments

### 1. Introduction

Indoor environments could be characterized by several pollutant sources. Environmental Protection Agency (EPA) is responsible for environmental air quality index regulation in the United States. This independent agency deliberates that indoor levels of contaminants can be up to 100 times greater than outdoor contaminant level and positioned poor air quality as one of the top five environmental dangers to the community well-being [1]. Thus, indoor air quality (IAQ) is recognized as an essential factor to be controlled for the occupants' health and comfort. Increase in the IAQ is critical as people typically spend more than 90% of their time in indoor environments. The problem of inadequate IAQ is of utmost importance affecting particularly severe form the poorest people in the world who are most vulnerable, presenting itself as a severe problem for world health such as tobacco use, alcoholism or the problem of sexually transmitted diseases [2].

In 1983, the World Health Organization (WHO) used the term "sick building syndrome" (SBS) to the clinical features that we might discover in building residents as a consequence of the poor IAQ [3]. Numerous statements have reported the influence of IAQ in the etiopathogenesis of various generic signs and medical results that illustrate SBS. The scientific representation of this pattern is widespread as it can engage the skin (with xerosis, pruritus), the upper and lower breathing tract (such as, dysphonia, dry cough and asthma), the eyes (ocular pruritus), and the nervous system (for example, headache and difficulty in concentration) [4, 5]. Furthermore, besides the symptoms of this disease, there are syndromes, which could be connected with indoor environments, i.e., Legionnaire's disease, extrinsic allergic alveolitis, asthma, and atopic dermatitis [4, 5]. For example, regarding atopic dermatitis, it is a chronic and inflammatory skin disorder and one of the most usual allergic syndromes in infants. Its occurrence is rising and, while it is related to hereditary influences, there is a considerable suggestion of responsibility for environmental factors, namely indoor air pollutants. This is mainly significant in industrialized nations, where youngsters apply most of their time inside buildings [6]. Including the air contaminants, the volatile organic compounds are connected to the exacerbation of atopic dermatitis, which remain the utmost deliberated usual pollutants of indoor air [5]. Universally acknowledged, in atopic dermatitis, indoor air contaminants could provoke oxidative stress, leading to skin barrier dysfunction or immune dysregulation [6]. Thus, the signs and syndromes related to the "sick buildings" are a problem with emergent significance in public health and have likewise been associated with lower productivity and greater absenteeism. The etiology of the SBS and the building associated disorders might incorporate chemical pollutants (both from outdoor and indoor sources), biological agents, emotional issues, electromagnetic radiation, the deficiency of sunlight, humidity, poor acoustics, deficient ergonomics, and bad ventilation [5]. Although the importance of indoor air quality for public health still exists, there is a lack of interest in the new scientific methods to improve indoor air quality in developed countries [7].

2. IoT and AAL for the enhanced indoor air quality

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

DOI: http://dx.doi.org/10.5772/intechopen.81478

tion Technologies (ICTs) [13].

humankind aging.

31

instead must be an extraordinary compliment.

Ambient assisted living (AAL) is closely related to the necessity of pervasive healthcare supervision, and the main aim is to contribute to the pervasion of the independence and well-being for older adults using Information and Communica-

Nowadays, there are numerous AAL solutions that can be found in literature that incorporate a large number of different types of sensors for biological supervision. These solutions typically incorporate wireless communication technologies for

At the second half of this century, 20% of the humankind will be of age 60 or above [14], which is linked with several complex problems for public health. First of all, this will provoke an increase in disorders, healthcare budget, and the scarcity of caretakers, which will conduct to a giant social impact. Another import argument is that people typically choose to remain in their homes even paying the cost of the nursing care [15], which indicate the research of AAL solutions architectures as unquestionably a subject of extraordinary significance taking into account the

AAL researches are planned to encounter the requirements of the elderly popu-

lation to preserve their independence as long as conceivable. On the one hand, improvements in telecommunications, sensors, and embedded processors conducted to the delivery of real-time supervising and personalized healthcare solutions to entities, which are able to be currently used in their habitats. On the other hand, these incessant scientific developments create the elaboration of smart cyber-physical systems for enhanced living environments and occupational health. Although there is a portion of issues in the creation of an effective AAL ecosystem such as data architecture, interface design, human-computer communication, ergonomics, usability and availability [16], there are also collective and moral difficulties as the recognition by the older people and the privacy and confidentiality that would stand as a prerequisite of the entirely AAL solutions. Indeed, it is likewise crucial to guarantee that technology does not substitute the human care but

Internet of Things (IoT) stands as a standard where things are linked to the Internet and incorporate data collection capabilities. The basic idea of the IoT is the pervasive presence of a variety of objects with interaction and cooperation capabilities among them to reach a common objective [17–19]. It is anticipated that the IoT will provoke a considerable effect on numerous characteristics of daily life and this paradigm will be incorporated in several purposes such as domotics, assisted living, e-health and is likewise a perfect emergent knowledge to offer novel evolving data and computational resources on behalf of generating groundbreaking software applications [20]. IoT architectures should incorporate wireless communication technologies. Nowadays, several wireless communication technologies are available such as bluetooth-based technologies, Wi-Fi-based technologies, nearfield communication (NFC)-based technologies, and GSM-based technologies. IoT solutions must stand pervasive, be context aware, and allow environment intelligence skills that are directly connected to AAL. IoT is an appropriate method to construct well-being solutions. Scientific developments turn possible to create novel and innovative instruments to empower real-time healthcare supervising solutions for decision-making in the management of several syndromes.

Nowadays, several IoT architectures had been implemented for clinical monitoring that claim IoT as a reliable platform to develop personalized healthcare systems. Due to Bluetooth technology, the use of wearables for data collection and

data sharing and collection such as ZigBee, Bluetooth, Ethernet, and Wi-Fi.

Ventilation is used in buildings to create thermally comfortable environments with acceptable IAQ by regulating indoor air parameters, such as air temperature, relative humidity, airspeed, and chemical species concentrations in the air [8]. An IAQ evaluation system provides an important way to find and enhance the indoor environmental quality. Local and distributed valuation of chemical concentrations is substantial not only for security (gas spills recognition, pollution supervising) and well-being applications but also for efficient temperature regulation, ventilation and air conditioning (HVAC) system for energy efficiency [9]. IAQ monitoring offers an uninterrupted stream of data for centralized regulation of building automation procedures, and delivers a solution for enhanced build management [10]. Real-time supervision of the IAQ is assumed as an essential tool of extreme importance to plan interventions for enhanced occupational health.

In recent past, numerous systems have been created on behalf of environmental supervision, constantly beside the intention to increase the IAQ [11]. The accessibility of cost-effective, energy efficient, and small-scale embedded computers, radios, sensors, and actuators, regularly incorporated on a unique chip, has been conducted for the incorporation of wireless communications to cooperate with the material world for IAQ supervision and enhanced living environments [12].

In this chapter, the authors present several new open-source and cost-effective systems that had been developed for monitoring environmental parameters, always with the aim of improving IAQ for enhanced healthy buildings. The chapter is structured as follows: besides the Introduction (Section 1), Section 2 introduces IoT and AAL themes, and Section 3 is concerned with presenting several IAQ systems for enhanced living environments, and Section 3.2 demonstrates a comparison between the proposed systems, and the conclusions are presented in Section 3.5.

influence of IAQ in the etiopathogenesis of various generic signs and medical results that illustrate SBS. The scientific representation of this pattern is widespread as it can engage the skin (with xerosis, pruritus), the upper and lower breathing tract (such as, dysphonia, dry cough and asthma), the eyes (ocular pruritus), and the nervous system (for example, headache and difficulty in concentration) [4, 5]. Furthermore, besides the symptoms of this disease, there are syndromes, which could be connected with indoor environments, i.e., Legionnaire's disease, extrinsic allergic alveolitis, asthma, and atopic dermatitis [4, 5]. For example, regarding atopic dermatitis, it is a chronic and inflammatory skin disorder and one of the most usual allergic syndromes in infants. Its occurrence is rising and, while it is related to hereditary influences, there is a considerable suggestion of responsibility for environmental factors, namely indoor air pollutants. This is mainly significant in industrialized nations, where youngsters apply most of their time inside buildings [6]. Including the air contaminants, the volatile organic compounds are connected to the exacerbation of atopic dermatitis, which remain the utmost deliberated usual pollutants of indoor air [5]. Universally acknowledged, in atopic dermatitis, indoor air contaminants could provoke oxidative stress, leading to skin barrier dysfunction or immune dysregulation [6]. Thus, the signs and syndromes related to the "sick buildings" are a problem with emergent significance in public health and have likewise been associated with lower productivity and greater absenteeism. The etiology of the SBS and the building associated disorders might incorporate chemi-

cal pollutants (both from outdoor and indoor sources), biological agents,

tance to plan interventions for enhanced occupational health.

countries [7].

Indoor Environmental Quality

30

emotional issues, electromagnetic radiation, the deficiency of sunlight, humidity, poor acoustics, deficient ergonomics, and bad ventilation [5]. Although the importance of indoor air quality for public health still exists, there is a lack of interest in the new scientific methods to improve indoor air quality in developed

Ventilation is used in buildings to create thermally comfortable environments with acceptable IAQ by regulating indoor air parameters, such as air temperature, relative humidity, airspeed, and chemical species concentrations in the air [8]. An IAQ evaluation system provides an important way to find and enhance the indoor environmental quality. Local and distributed valuation of chemical concentrations is substantial not only for security (gas spills recognition, pollution supervising) and well-being applications but also for efficient temperature regulation, ventilation and air conditioning (HVAC) system for energy efficiency [9]. IAQ monitoring offers an uninterrupted stream of data for centralized regulation of building automation procedures, and delivers a solution for enhanced build management [10]. Real-time supervision of the IAQ is assumed as an essential tool of extreme impor-

In recent past, numerous systems have been created on behalf of environmental supervision, constantly beside the intention to increase the IAQ [11]. The accessibility of cost-effective, energy efficient, and small-scale embedded computers, radios, sensors, and actuators, regularly incorporated on a unique chip, has been conducted for the incorporation of wireless communications to cooperate with the material world for IAQ supervision and enhanced living environments [12].

In this chapter, the authors present several new open-source and cost-effective systems that had been developed for monitoring environmental parameters, always with the aim of improving IAQ for enhanced healthy buildings. The chapter is structured as follows: besides the Introduction (Section 1), Section 2 introduces IoT and AAL themes, and Section 3 is concerned with presenting several IAQ systems for enhanced living environments, and Section 3.2 demonstrates a comparison between the proposed systems, and the conclusions are presented in Section 3.5.

### 2. IoT and AAL for the enhanced indoor air quality

Ambient assisted living (AAL) is closely related to the necessity of pervasive healthcare supervision, and the main aim is to contribute to the pervasion of the independence and well-being for older adults using Information and Communication Technologies (ICTs) [13].

Nowadays, there are numerous AAL solutions that can be found in literature that incorporate a large number of different types of sensors for biological supervision. These solutions typically incorporate wireless communication technologies for data sharing and collection such as ZigBee, Bluetooth, Ethernet, and Wi-Fi.

At the second half of this century, 20% of the humankind will be of age 60 or above [14], which is linked with several complex problems for public health. First of all, this will provoke an increase in disorders, healthcare budget, and the scarcity of caretakers, which will conduct to a giant social impact. Another import argument is that people typically choose to remain in their homes even paying the cost of the nursing care [15], which indicate the research of AAL solutions architectures as unquestionably a subject of extraordinary significance taking into account the humankind aging.

AAL researches are planned to encounter the requirements of the elderly population to preserve their independence as long as conceivable. On the one hand, improvements in telecommunications, sensors, and embedded processors conducted to the delivery of real-time supervising and personalized healthcare solutions to entities, which are able to be currently used in their habitats. On the other hand, these incessant scientific developments create the elaboration of smart cyber-physical systems for enhanced living environments and occupational health. Although there is a portion of issues in the creation of an effective AAL ecosystem such as data architecture, interface design, human-computer communication, ergonomics, usability and availability [16], there are also collective and moral difficulties as the recognition by the older people and the privacy and confidentiality that would stand as a prerequisite of the entirely AAL solutions. Indeed, it is likewise crucial to guarantee that technology does not substitute the human care but instead must be an extraordinary compliment.

Internet of Things (IoT) stands as a standard where things are linked to the Internet and incorporate data collection capabilities. The basic idea of the IoT is the pervasive presence of a variety of objects with interaction and cooperation capabilities among them to reach a common objective [17–19]. It is anticipated that the IoT will provoke a considerable effect on numerous characteristics of daily life and this paradigm will be incorporated in several purposes such as domotics, assisted living, e-health and is likewise a perfect emergent knowledge to offer novel evolving data and computational resources on behalf of generating groundbreaking software applications [20]. IoT architectures should incorporate wireless communication technologies. Nowadays, several wireless communication technologies are available such as bluetooth-based technologies, Wi-Fi-based technologies, nearfield communication (NFC)-based technologies, and GSM-based technologies.

IoT solutions must stand pervasive, be context aware, and allow environment intelligence skills that are directly connected to AAL. IoT is an appropriate method to construct well-being solutions. Scientific developments turn possible to create novel and innovative instruments to empower real-time healthcare supervising solutions for decision-making in the management of several syndromes.

Nowadays, several IoT architectures had been implemented for clinical monitoring that claim IoT as a reliable platform to develop personalized healthcare systems. Due to Bluetooth technology, the use of wearables for data collection and smartphones for data transmission is now possible to provide physiological parameter supervision [20]. In 2009, several research initiatives for remote healthcare was been developed using IoT. Furthermore, IoT can increase the knowledge of data collection, which support IoT solutions in the medical area [21]. On behalf of the potential of the IoT concept for wellbeing solutions nowadays several challenges to be overcome still subsist.

The influence and impact of the IoT in the today's market is not clearly known, as well as the acceptance of pervasive and ubiquitous IoT products. Although the scientific advancements that turn IoT healthcare systems currently are feasible, the timing might be too early [22].

The "smart city" conception has lately presented as a tactical strategy to face contemporary municipal manufacture features in a mutual framework and, in specific, to focus the significance of ICT in the previous 20 years for increasing the economical profile of a city as suggested by [23]. Currently, cities have fascinating challenges and complications to gather socioeconomic progress and quality of life intents. The "smart cities" are related to react to these problems [24]. The smart city is also straightly connected to an emergent approach to decrease the difficulties produced by the urban population progress and quick urbanization [25]. The highest significant challenge in smart cities is the interoperability of the diverse technologies. IoT might be able to offer the interoperability to develop an integrated urban-scale ICT architecture for smart cities [26]. The smart city execution will produce effects at diverse stages such as effects on science, effects on technology and competitiveness, and effects on culture; however, this will likewise provoke ethical concerns as the smart city requires to offer accurate data access as it becomes fundamental, once such data are accessible at a fine spatial scale where people can be recognized [27]. IoT has an important potential to build novel real-life solutions and services for the smart city background [28].

#### 3. Indoor air quality monitoring systems

Several solutions have been developed to improve the occupational health, aiming to provide real-time monitoring of indoor environments for enhanced living environments and occupational health. These solutions could revolutionize the indoor environments contributing to enhanced healthy buildings and to decrease the SBS problem. Some systems developed by the authors are described below.

linked to the Internet through an Arduino Ethernet Shield, is responsible for the

The Web portal iAQ Web was been developed in PHP and supports authentication. This Web portal is responsible for the availability of the data to the end user. Accessing the iAQ Web is possible to analyze the environmental quality. The data can be analyzed as numeric values or in chart form. The iAQ Web is prepared with a notification manager that notifies the user in case a particular parameter overdoes the maximum value. This portal additionally acknowledges the user to retain the parameters' history. Offering a history of changes, this system provides an evaluation platform to accurately analyze the IAQ behavior. Furthermore, it is possible to take actions in the environment to increase the air quality in the building in

The wireless communication features are created with the ZigBee networking protocol. Several XBee modules are used to implement the IEEE 802.15.4 radio standard [30]. This standard identifies the physical and medium access control

data storage.

iAQ Sensor hardware, from [29].

Figure 2.

Figure 1.

iAQ WSN architecture, from [29].

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

DOI: http://dx.doi.org/10.5772/intechopen.81478

real time.

33

#### 3.1 iAQ system

iAQ system [29] is an automatic low-cost indoor air quality monitoring wireless sensor network system, developed using Arduino, XBee modules, and microsensors. This solution can be accessed by the building supervisor to identify a diversity of factors as temperature, humidity, luminosity, carbon dioxide (CO2), and carbon monoxide (CO), in real time. Other parameters can be analyzed for particular contaminants as other sensors might be added for data collection.

The iAQ Sensor is responsible for the environmental data collection and to transmit these data to the iAQ Gateway. The iAQ Gateway uses Web services to provide data transmission and storage in a MySQL database. The Web services was been developed in PHP (Figure 1).

The iAQ system can incorporate one or more iAQ Sensors (Figure 2). The iAQ Sensors not only collect data from the environment but also send these data to the iAQ Gateway and can be placed in different locations. The iAQ Gateway, which is Indoor Air Quality Monitoring for Enhanced Healthy Buildings DOI: http://dx.doi.org/10.5772/intechopen.81478

Figure 1. iAQ WSN architecture, from [29].

smartphones for data transmission is now possible to provide physiological parameter supervision [20]. In 2009, several research initiatives for remote healthcare was been developed using IoT. Furthermore, IoT can increase the knowledge of data collection, which support IoT solutions in the medical area [21]. On behalf of the potential of the IoT concept for wellbeing solutions nowadays several challenges to

The influence and impact of the IoT in the today's market is not clearly known, as well as the acceptance of pervasive and ubiquitous IoT products. Although the scientific advancements that turn IoT healthcare systems currently are feasible, the

The "smart city" conception has lately presented as a tactical strategy to face contemporary municipal manufacture features in a mutual framework and, in specific, to focus the significance of ICT in the previous 20 years for increasing the economical profile of a city as suggested by [23]. Currently, cities have fascinating challenges and complications to gather socioeconomic progress and quality of life intents. The "smart cities" are related to react to these problems [24]. The smart city is also straightly connected to an emergent approach to decrease the difficulties produced by the urban population progress and quick urbanization [25]. The highest significant challenge in smart cities is the interoperability of the diverse technologies. IoT might be able to offer the interoperability to develop an integrated urban-scale ICT architecture for smart cities [26]. The smart city execution will produce effects at diverse stages such as effects on science, effects on technology and competitiveness, and effects on culture; however, this will likewise provoke ethical concerns as the smart city requires to offer accurate data access as it becomes fundamental, once such data are accessible at a fine spatial scale where people can be recognized [27]. IoT has an important potential to build novel real-life solutions

Several solutions have been developed to improve the occupational health, aiming to provide real-time monitoring of indoor environments for enhanced living environments and occupational health. These solutions could revolutionize the indoor environments contributing to enhanced healthy buildings and to decrease the SBS problem. Some systems developed by the authors are described below.

iAQ system [29] is an automatic low-cost indoor air quality monitoring wireless sensor network system, developed using Arduino, XBee modules, and microsensors. This solution can be accessed by the building supervisor to identify a diversity of factors as temperature, humidity, luminosity, carbon dioxide (CO2), and carbon monoxide (CO), in real time. Other parameters can be analyzed for particular

The iAQ Sensor is responsible for the environmental data collection and to transmit these data to the iAQ Gateway. The iAQ Gateway uses Web services to provide data transmission and storage in a MySQL database. The Web services was

The iAQ system can incorporate one or more iAQ Sensors (Figure 2). The iAQ Sensors not only collect data from the environment but also send these data to the iAQ Gateway and can be placed in different locations. The iAQ Gateway, which is

contaminants as other sensors might be added for data collection.

be overcome still subsist.

Indoor Environmental Quality

timing might be too early [22].

and services for the smart city background [28].

3. Indoor air quality monitoring systems

3.1 iAQ system

32

been developed in PHP (Figure 1).

Figure 2. iAQ Sensor hardware, from [29].

linked to the Internet through an Arduino Ethernet Shield, is responsible for the data storage.

The Web portal iAQ Web was been developed in PHP and supports authentication. This Web portal is responsible for the availability of the data to the end user. Accessing the iAQ Web is possible to analyze the environmental quality. The data can be analyzed as numeric values or in chart form. The iAQ Web is prepared with a notification manager that notifies the user in case a particular parameter overdoes the maximum value. This portal additionally acknowledges the user to retain the parameters' history. Offering a history of changes, this system provides an evaluation platform to accurately analyze the IAQ behavior. Furthermore, it is possible to take actions in the environment to increase the air quality in the building in real time.

The wireless communication features are created with the ZigBee networking protocol. Several XBee modules are used to implement the IEEE 802.15.4 radio standard [30]. This standard identifies the physical and medium access control

layers for low data-rate personal networks. ZigBee is a cost-effective, energy efficient, support mesh networks standard and was develop upon 802.15.4. Radio waves are transmitted from iAQ Sensor to the base station iAQ Gateway.

locations that correspond to a specific iAQ Sensor node. The user can access to the current humidity, temperature, carbon dioxide, carbon monoxide, and light values. Using the mobile app, the user can likewise rapidly access to the alerts generated

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

DOI: http://dx.doi.org/10.5772/intechopen.81478

when the monitored parameters exceed the minimum or the maximum values.

iAQ solution has also been updated to adopt an IoT architecture using the ESP8266 and be a fully wireless solution for IAQ. iAQ IoT Gateway [33] has replaced the Arduino by a Wemos Mini D1 (Wemos Electronics) as a processing unit. The processing unit is a miniaturized Wi-Fi board based on ESP-8266EX. This board incorporates 11digital input pins and 1 digital output pin, and 1 analogue input pin. The interface used for programming and power is micro-USB. Wemos Mini D1 can be programmed using the Arduino IDE and incorporate 32 bits CPU with an 80/ 160 MHz clock speed, which works at 3.3 V, 4 Mb flash, and has 34.2 25.6 mm

A majority of the IAQ supervision solutions currently available on the market are especially expensive and only permit the collection of arbitrary values from the environment. iAQ IoT is an IAQ solution developed on top of the IoT concept that integrates in its assembly Arduino, ESP8266, and XBee technologies for data

iAQ IoT Gateway incorporates only wireless communication technologies to interact with the nodes as well as for Internet accessibility. It collects data from iAQ Sensor using an XBee module and then uses Wi-Fi to provide data storage to a MySQL database using Web services. The schematic and connections used in iAQ

iAQ Wi-Fi [34] is a real-time indoor air quality monitoring solution that is capable of measuring temperature, humidity, PM10, CO2, and luminosity in real time. This solution is based on the IoT concept and is fully wireless. The access to the Internet in order to provide data storage of the monitored parameters is developed using the ESP8266 chip, which implements the IEEE 802.11 b/g/n networking

This solution incorporates open-source technologies, using an Arduino UNO as a microcontroller as processing unit and an ESP8266 module as the communication unit. The monitored data are uploaded to the ThingSpeak platform. ThingSpeak is an

protocol and supports radio transmission within the 2.4 GHz band.

processing and transmission and sensors for data collection.

3.3 iAQ IoT system

size and a weight of 10 g.

Gateway are described in Figure 4.

3.4 iAQ Wi-Fi system

Figure 4.

35

iAQ IoT Gateway, from [33].

### 3.2 iAQ mobile system

Currently, smartphones incorporate high processing specifications aside from a diversity of sensors appropriated to the research and development of AAL systems. Sensors such as global position system (GPS), bluetooth low energy (BLE), camera, microphone, luminosity, accelerometer, gyroscope, and near-field communication (NFC).

As for the importance of the smartphone's role in human life, iAQ solution has been updated with an Android application [31, 32]. This mobile application was designed to provide quick and easy access to iAQ system to allow the end user to keep all the relevant information of iAQ system in your pocket.

This application provides data authentication and protection mechanisms for information visualizations and allows one to view system data in detail and receive notifications when any of the values exceed normal values.

This mobile application was developed for the android mobile operating system. The integrated development environment (IDE) Android Studio was used to build the application. The minimum requirement is the application programming interface (API) 15: Android 4.0.3 Ice Cream Sandwich. According to the IDE, this mobile app is compatible with 96.2% of active devices in the Google play store (information collected on January 22, 2016).

Figure 3 represents the mobile application features. The left image represents the login screen of the application that guarantees the authentication before data access. The right image represents the ability to select one of the monitored

Figure 3. Android app, from [33].

locations that correspond to a specific iAQ Sensor node. The user can access to the current humidity, temperature, carbon dioxide, carbon monoxide, and light values.

Using the mobile app, the user can likewise rapidly access to the alerts generated when the monitored parameters exceed the minimum or the maximum values.

### 3.3 iAQ IoT system

layers for low data-rate personal networks. ZigBee is a cost-effective, energy efficient, support mesh networks standard and was develop upon 802.15.4. Radio waves are transmitted from iAQ Sensor to the base station iAQ Gateway.

Currently, smartphones incorporate high processing specifications aside from a diversity of sensors appropriated to the research and development of AAL systems.

As for the importance of the smartphone's role in human life, iAQ solution has been updated with an Android application [31, 32]. This mobile application was designed to provide quick and easy access to iAQ system to allow the end user to

This application provides data authentication and protection mechanisms for information visualizations and allows one to view system data in detail and receive

This mobile application was developed for the android mobile operating system. The integrated development environment (IDE) Android Studio was used to build the application. The minimum requirement is the application programming interface (API) 15: Android 4.0.3 Ice Cream Sandwich. According to the IDE, this mobile app is compatible with 96.2% of active devices in the Google play store (information

Figure 3 represents the mobile application features. The left image represents the login screen of the application that guarantees the authentication before data access. The right image represents the ability to select one of the monitored

Sensors such as global position system (GPS), bluetooth low energy (BLE), camera, microphone, luminosity, accelerometer, gyroscope, and near-field com-

keep all the relevant information of iAQ system in your pocket.

notifications when any of the values exceed normal values.

3.2 iAQ mobile system

Indoor Environmental Quality

munication (NFC).

collected on January 22, 2016).

Figure 3.

34

Android app, from [33].

iAQ solution has also been updated to adopt an IoT architecture using the ESP8266 and be a fully wireless solution for IAQ. iAQ IoT Gateway [33] has replaced the Arduino by a Wemos Mini D1 (Wemos Electronics) as a processing unit. The processing unit is a miniaturized Wi-Fi board based on ESP-8266EX. This board incorporates 11digital input pins and 1 digital output pin, and 1 analogue input pin. The interface used for programming and power is micro-USB. Wemos Mini D1 can be programmed using the Arduino IDE and incorporate 32 bits CPU with an 80/ 160 MHz clock speed, which works at 3.3 V, 4 Mb flash, and has 34.2 25.6 mm size and a weight of 10 g.

A majority of the IAQ supervision solutions currently available on the market are especially expensive and only permit the collection of arbitrary values from the environment. iAQ IoT is an IAQ solution developed on top of the IoT concept that integrates in its assembly Arduino, ESP8266, and XBee technologies for data processing and transmission and sensors for data collection.

iAQ IoT Gateway incorporates only wireless communication technologies to interact with the nodes as well as for Internet accessibility. It collects data from iAQ Sensor using an XBee module and then uses Wi-Fi to provide data storage to a MySQL database using Web services. The schematic and connections used in iAQ Gateway are described in Figure 4.

### 3.4 iAQ Wi-Fi system

iAQ Wi-Fi [34] is a real-time indoor air quality monitoring solution that is capable of measuring temperature, humidity, PM10, CO2, and luminosity in real time. This solution is based on the IoT concept and is fully wireless. The access to the Internet in order to provide data storage of the monitored parameters is developed using the ESP8266 chip, which implements the IEEE 802.11 b/g/n networking protocol and supports radio transmission within the 2.4 GHz band.

This solution incorporates open-source technologies, using an Arduino UNO as a microcontroller as processing unit and an ESP8266 module as the communication unit. The monitored data are uploaded to the ThingSpeak platform. ThingSpeak is an

Figure 4. iAQ IoT Gateway, from [33].

open-source IoT platform that offers APIs for storing and retrieving data from sensors and devices using HTTP [12]. iAQ Wi-Fi prototype is represented in Figure 5.

ESP8266 is connected to the Internet using Wi-Fi and is responsible for uploading

The mobile application is denominated by iAQ Wi-Fi Mobile (Figure 7), and is developed using XCODE IDE and SWIFT programming language. The iAQ Wi-Fi Mobile has the iOS 7 as the minimum requirement. The mobile application provides authentication to authorized users. The end user after login can analyze the history-

iAirC is a solution for carbon dioxide (CO2) real-time monitoring based on IoT architecture. To have a low-cost system, only one type of indoor air pollutant was

In one hand, when the CO2 level extends 7–10%, an individual can lose consciousness within minutes and might stand at risk of death. On the other hand, a low intensity of CO2 stands inoffensive to humans. It is well known that CO2 levels are linked with dizziness and sleepiness leading to low productivity at work [36]. Therefore, it is significant to provide a real-time CO2 supervision and develop a notification system for enhanced living environments. The intensity of CO2—the main greenhouse gas—is steadily increased to 400 ppm (ppm), reaching new

CO2 was chosen because it is easy to measure, and it is produced in quantity from multiple sources (by people and combustion equipment). Consequently, it should be assumed as an indicator of other contaminants, and consequently of IAQ

The iAirC solution incorporates a prototype for environmental data collection and a mobile application for data access and supervision. This solution use Wi-Fi for Internet access, which conduct to a diversity of advantages such as modularity, scalability, low-cost and easy installation. The data are stored in the ThingSpeak

the data received to the ThingSpeak platform.

DOI: http://dx.doi.org/10.5772/intechopen.81478

3.5 iAirC system

chosen [35].

in common.

Figure 7.

37

iAQ Wi-Fi mobile app, from [34].

monitored data in numerical or graphical representation.

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

records every year since they began to be produced in 1984 [37].

The end user can access the data from the Web page provided by ThingSpeak platform or can use the smartphone app developed in SWIFT, an open-source programming language with XCODE IDE created for iOS operating system. iAQ Wi-Fi system architecture is based on IoT. Figure 6 represents the system architecture used by the authors.

The Arduino UNO incorporates sensors that are responsible for the data collection and send that information to the ESP8266 by serial communication. The

Figure 5. iAQ Wi-Fi prototype, from [34].

Figure 6. iAQ Wi-Fi system architecture, from [34].

### Indoor Air Quality Monitoring for Enhanced Healthy Buildings DOI: http://dx.doi.org/10.5772/intechopen.81478

ESP8266 is connected to the Internet using Wi-Fi and is responsible for uploading the data received to the ThingSpeak platform.

The mobile application is denominated by iAQ Wi-Fi Mobile (Figure 7), and is developed using XCODE IDE and SWIFT programming language. The iAQ Wi-Fi Mobile has the iOS 7 as the minimum requirement. The mobile application provides authentication to authorized users. The end user after login can analyze the historymonitored data in numerical or graphical representation.

### 3.5 iAirC system

open-source IoT platform that offers APIs for storing and retrieving data from sensors and devices using HTTP [12]. iAQ Wi-Fi prototype is represented

The end user can access the data from the Web page provided by ThingSpeak platform or can use the smartphone app developed in SWIFT, an open-source programming language with XCODE IDE created for iOS operating system. iAQ Wi-Fi system architecture is based on IoT. Figure 6 represents the system architec-

The Arduino UNO incorporates sensors that are responsible for the data collec-

tion and send that information to the ESP8266 by serial communication. The

in Figure 5.

Figure 5.

Figure 6.

36

iAQ Wi-Fi system architecture, from [34].

iAQ Wi-Fi prototype, from [34].

ture used by the authors.

Indoor Environmental Quality

iAirC is a solution for carbon dioxide (CO2) real-time monitoring based on IoT architecture. To have a low-cost system, only one type of indoor air pollutant was chosen [35].

In one hand, when the CO2 level extends 7–10%, an individual can lose consciousness within minutes and might stand at risk of death. On the other hand, a low intensity of CO2 stands inoffensive to humans. It is well known that CO2 levels are linked with dizziness and sleepiness leading to low productivity at work [36]. Therefore, it is significant to provide a real-time CO2 supervision and develop a notification system for enhanced living environments. The intensity of CO2—the main greenhouse gas—is steadily increased to 400 ppm (ppm), reaching new records every year since they began to be produced in 1984 [37].

CO2 was chosen because it is easy to measure, and it is produced in quantity from multiple sources (by people and combustion equipment). Consequently, it should be assumed as an indicator of other contaminants, and consequently of IAQ in common.

The iAirC solution incorporates a prototype for environmental data collection and a mobile application for data access and supervision. This solution use Wi-Fi for Internet access, which conduct to a diversity of advantages such as modularity, scalability, low-cost and easy installation. The data are stored in the ThingSpeak

Figure 7. iAQ Wi-Fi mobile app, from [34].

cloud platform and then can be consulted using the mobile app or ThingSpeak Web portal.

PM exposure data can be exceptionally precious to provide support to a clinical examination by medical experts as the therapeutic panel could analyze the record of IAQ factors of the environment everywhere the patient resides and link this reports alongside his health problems. On the other hand, by supervising IAQ, it stands plausible to identify the air quality circumstances appropriately plus, if

iDust stands as an ICT solution for real-time IAQ managing that allows the end user, as the building manager to analyze the PM exposure behavior. This system incorporates WEMOS D1 mini as a microcontroller and is developed using the Arduino IDE. The parameters are supervised using the iDust prototype, which is responsible for data collection. The monitored data are stored in a SQL SERVER database using Web services built in .NET. An authenticated user is able to access the IAQ information using the Web portal created in ASP.NET. The information collected is accessible in a dashboard in mutually numeric values or graph form. Likewise, the Web portal stores the history of the PM exposure behavior. The Web application incorporates a important notification manager that notifies the build manager when a particular parameter exceeds the maximum value. iDust is a costeffective, consistent method, which can easily be parametrized and installed by the regular people. On behalf of this, the authors had selected a cost-effective but very reliable PM sensor and a microcontroller with built-in Wi-Fi communication technology. This architecture incorporates of two components: a microcontroller and a PMS5003 PM sensor (Plantower), which features scattering method to quantify the rate of particles suspended in the air with a diameter of 10 microns or less (≤PM10),

required, plan interventions to drop the PM exposure concentrations.

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

DOI: http://dx.doi.org/10.5772/intechopen.81478

2.5 microns or less (≤PM2.5), and 1.0 microns or less (≤PM1.0)(Figure 9).

is by default a Wi-Fi client, although when a known Wi-Fi network is not

network to configure the Wi-Fi network to which the iDust is going to be connected. The regular user must introduce the SSID and password using a Web

accurate and detailed analysis of the PM exposure behavior.

form as represented in Figure 11.

Figure 9.

39

iDust connection diagram, from [41].

The Web application allows the build manager to save the parameters' history as is presented in Figure 10. Providing a history of changes turns possible to do an

iDust system uses the ESP8266 for both processing and Internet connectivity. The incorporation of the ESP8266 has an additional significant functionality as it offers to the regular user an easy configuration of the Wi-Fi network. The ESP8266

available, or in case there are no wireless networks available, the ESP8266 will turn to hotspot mode and will transmit a Wi-Fi network with an service set identifier (SSID) "IAQ-iDust." After that, the regular user could be connected to this Wi-Fi

iAirC consists of two components, an ESP8266 Thing Dev (Sparkfun) microcontroller and an MHZ-19 carbon dioxide sensor developed by Winsensor (Figure 8).

The ESP8266 Sparkfun microcontroller incorporates integrated Wi-Fi features and is used mutually for data processing and communication. The iAirC is a lowcost, reliable system that can be easily configured and installed by the average user. For this, iAirC incorporates a low cost but very reliable carbon dioxide sensor and a microcontroller with native Wi-Fi support.

The mobile application is denominated by iAirC Mobile (Figure 8), and is developed using XCODE IDE and SWIFT programming language [38]. Using the iAirC Mobile, the end user after authentication not only can access to real-time CO2 levels but also to be notified when the IAQ is defective (Figure 8).

Ample physical evidence shows that CO2 is the single most important climaterelevant greenhouse gas in Earth's atmosphere and high external charges mean that they naturally lead to higher indoor concentrations due to the contribution of the internal sources (human metabolism and combustion equipment) [39, 40]. It is imperative to control the concentration of CO2 effectively and the authors believe that the first step is to monitor to perceive its variation in real time and to plan interventions for its reduction.

### 3.6 iDust

PM is related to numerous serious health problems. iDust is a real-time PM exposure monitoring system and decision-making tool for enhanced healthcare based on an IoT architecture [41]. It was developed using open-source technologies and low-cost sensors.

This architecture has been developed in order to provide an evaluation platform that can be acceded to by the building manager in order to analyze the PM behavior of the indoor environment in detail. Furthermore, the build manager can take action in real time in order to provide a safe and healthful place for the occupants.

Figure 8. iAirC prototype (left); and iAirC Mobile (right), from [35].

Indoor Air Quality Monitoring for Enhanced Healthy Buildings DOI: http://dx.doi.org/10.5772/intechopen.81478

cloud platform and then can be consulted using the mobile app or ThingSpeak Web

The mobile application is denominated by iAirC Mobile (Figure 8), and is developed using XCODE IDE and SWIFT programming language [38]. Using the iAirC Mobile, the end user after authentication not only can access to real-time CO2

Ample physical evidence shows that CO2 is the single most important climaterelevant greenhouse gas in Earth's atmosphere and high external charges mean that they naturally lead to higher indoor concentrations due to the contribution of the internal sources (human metabolism and combustion equipment) [39, 40]. It is imperative to control the concentration of CO2 effectively and the authors believe that the first step is to monitor to perceive its variation in real time and to plan

PM is related to numerous serious health problems. iDust is a real-time PM exposure monitoring system and decision-making tool for enhanced healthcare based on an IoT architecture [41]. It was developed using open-source technologies

This architecture has been developed in order to provide an evaluation platform that can be acceded to by the building manager in order to analyze the PM behavior of the indoor environment in detail. Furthermore, the build manager can take action in real time in order to provide a safe and healthful place for the occupants.

levels but also to be notified when the IAQ is defective (Figure 8).

iAirC consists of two components, an ESP8266 Thing Dev (Sparkfun) microcontroller and an MHZ-19 carbon dioxide sensor developed by Winsensor (Figure 8). The ESP8266 Sparkfun microcontroller incorporates integrated Wi-Fi features and is used mutually for data processing and communication. The iAirC is a lowcost, reliable system that can be easily configured and installed by the average user. For this, iAirC incorporates a low cost but very reliable carbon dioxide sensor and a

portal.

Indoor Environmental Quality

microcontroller with native Wi-Fi support.

interventions for its reduction.

3.6 iDust

Figure 8.

38

iAirC prototype (left); and iAirC Mobile (right), from [35].

and low-cost sensors.

PM exposure data can be exceptionally precious to provide support to a clinical examination by medical experts as the therapeutic panel could analyze the record of IAQ factors of the environment everywhere the patient resides and link this reports alongside his health problems. On the other hand, by supervising IAQ, it stands plausible to identify the air quality circumstances appropriately plus, if required, plan interventions to drop the PM exposure concentrations.

iDust stands as an ICT solution for real-time IAQ managing that allows the end user, as the building manager to analyze the PM exposure behavior. This system incorporates WEMOS D1 mini as a microcontroller and is developed using the Arduino IDE. The parameters are supervised using the iDust prototype, which is responsible for data collection. The monitored data are stored in a SQL SERVER database using Web services built in .NET. An authenticated user is able to access the IAQ information using the Web portal created in ASP.NET. The information collected is accessible in a dashboard in mutually numeric values or graph form. Likewise, the Web portal stores the history of the PM exposure behavior. The Web application incorporates a important notification manager that notifies the build manager when a particular parameter exceeds the maximum value. iDust is a costeffective, consistent method, which can easily be parametrized and installed by the regular people. On behalf of this, the authors had selected a cost-effective but very reliable PM sensor and a microcontroller with built-in Wi-Fi communication technology. This architecture incorporates of two components: a microcontroller and a PMS5003 PM sensor (Plantower), which features scattering method to quantify the rate of particles suspended in the air with a diameter of 10 microns or less (≤PM10), 2.5 microns or less (≤PM2.5), and 1.0 microns or less (≤PM1.0)(Figure 9).

The Web application allows the build manager to save the parameters' history as is presented in Figure 10. Providing a history of changes turns possible to do an accurate and detailed analysis of the PM exposure behavior.

iDust system uses the ESP8266 for both processing and Internet connectivity. The incorporation of the ESP8266 has an additional significant functionality as it offers to the regular user an easy configuration of the Wi-Fi network. The ESP8266 is by default a Wi-Fi client, although when a known Wi-Fi network is not available, or in case there are no wireless networks available, the ESP8266 will turn to hotspot mode and will transmit a Wi-Fi network with an service set identifier (SSID) "IAQ-iDust." After that, the regular user could be connected to this Wi-Fi network to configure the Wi-Fi network to which the iDust is going to be connected. The regular user must introduce the SSID and password using a Web form as represented in Figure 11.

Figure 9. iDust connection diagram, from [41].


#### Figure 10.

iDust Web application, from [41].

Figure 11. iDust Wi-Fi configuration, from [41].

### 4. Discussion

Several solutions for IAQ supervision, which support open-source technologies for data processing, collection, and transmission that offers mobile computing architectures for real-time data accessibility, was presented in Section 3. Mainly, IAQ monitoring is a trending topic for which some other low-cost and open-source monitoring systems had been developed.

A summary of these studies is presented in Table 1.

In general, all the systems presented not only use cost-effective sensors and use open-source technologies, but also have notification systems that allow users to act in real time to significantly improve indoor air quality through the ventilation or deactivation of pollutant equipment. The presented solutions make a significant contribution compared to existing air quality monitoring systems due to its low cost of construction, installation, modularity, scalability, and easy access to monitoring data in real time through the Web and mobile applications. All the presented

MCU

41

iAQ iAQ

Arduino

CO2

Temperature,

 relative humidity luminosity,

 CO,

WSN

√

 √

ZigBee,

Mobile

 MySQL

Ethernet

Mobile

iAQ IoT

iAQ Wi-

Arduino, ESP8266

CO2, particulate matter,

humidity

temperature,

 relative

IoT IoT IoT

√

 √

Wi-Fi

 Web,

SQL Server √

mobile

√

 √

Wi-Fi

 Mobile

 Cloud

√

√

 √

Wi-Fi

 Web, mobile

Cloud

√

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

Fi iAirC

Sparkfun

CO2,

ESP8266

iDust

MCU: Table 1.

Summary of the presented systems for real-time indoor air quality monitoring.

microcontroller;

√: apply; : not apply.

Wemos D1 Mini Particulate matter

Arduino,

Temperature,

 relative humidity luminosity,

 CO,

WSN/IoT

√

 √

ZigBee, Wi-Fi

 Web,

MySQL

DOI: http://dx.doi.org/10.5772/intechopen.81478

mobile

ESP8266

CO2

Arduino

CO2

Temperature,

 relative humidity luminosity,

 CO,

WSN

√

 √

ZigBee,

Web

 MySQL

Ethernet

Sensors

Architecture

 Low

Opensource

Connectivity

 Data access

Data storage

User installation

cost


#### Table 1.

Summary of the presented systems for real-time indoor air quality monitoring.

### Indoor Air Quality Monitoring for Enhanced Healthy Buildings DOI: http://dx.doi.org/10.5772/intechopen.81478

4. Discussion

iDust Wi-Fi configuration, from [41].

Figure 11.

40

Figure 10.

iDust Web application, from [41].

Indoor Environmental Quality

monitoring systems had been developed.

A summary of these studies is presented in Table 1.

Several solutions for IAQ supervision, which support open-source technologies for data processing, collection, and transmission that offers mobile computing architectures for real-time data accessibility, was presented in Section 3. Mainly, IAQ monitoring is a trending topic for which some other low-cost and open-source

In general, all the systems presented not only use cost-effective sensors and use open-source technologies, but also have notification systems that allow users to act in real time to significantly improve indoor air quality through the ventilation or deactivation of pollutant equipment. The presented solutions make a significant contribution compared to existing air quality monitoring systems due to its low cost of construction, installation, modularity, scalability, and easy access to monitoring data in real time through the Web and mobile applications. All the presented

solutions aim to offer the support to a medical examination by clinical professionals as the medical team might analyze the history of IAQ parameters collected from the environments where the patient lives and relate these records with his health complications.

be used to provide a detailed stream of data that can be used by the building manager for correct maintenance to offer not only a safe but also a healthy envi-

On the one hand, the real-time monitoring is a significant method to support the clinical analysis by medical specialists as the therapeutic team could analyze the history of IAQ conditions of the environment where the patient resides and link these data with his health problems. On the other hand, by supervising IAQ, it is conceivable to identify the poor air quality situations appropriately and plan inter-

The WSN architecture is appropriated to large buildings with no Wi-Fi networks available. However, the IoT architecture is appropriated to domestic homes as the majority provide Wi-Fi access points and also because the easy installation and configuration allows the user to start with a few devices and increase the number of

In the opinion of the authors, the future of air quality monitoring solutions focuses on the development of Wi-Fi systems that incorporate only one sensor. In this way, the user can not only create an ecosystem to suit them by monitoring the parameters he wants, but can also make the systems more cost-effective and easier

As a future work, the proposed solutions should plan software and hardware improvements to fit specific cases such as hospitals, schools, and industry. It is also essential to create secure methods for data sharing between the medical team in order to support clinical diagnostics. The authors believe that in the future, systems like the presented ones will be used as an integral part of the daily human routine in

The financial support from the Research Unit for Inland Development of the

Unit for Inland Development, Polytechnic Institute of Guarda, Guarda, Portugal

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

order to provide safe and productive living environments.

Polytechnic Institute of Guarda is acknowledged.

The authors declare no conflict of interest.

\*Address all correspondence to: rpitarma@ipg.pt

provided the original work is properly cited.

ronment for enhanced living environments.

DOI: http://dx.doi.org/10.5772/intechopen.81478

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

ventions for enhanced living environments.

them as he needs.

Acknowledgements

Conflict of interest

Author details

43

Gonçalo Marques and Rui Pitarma\*

to install.

An essential advantage of the use of ZigBee communication (iAQ, iAQ Mobile and iAQ IoT) is that we can have many iAQ Sensors collecting indoor air quality data, and only one iAQ Gateway must be connected to the Internet as Zigbee have an indoor RF line-of-sight range up to 50 m. It is essential for some scenarios, in this way, as it is no longer being required for Wi-Fi network coverage throughout all area of housing and it needs only an Internet connection at the location of iAQ Gateway.

Of about 56% of American adults are now smartphone holders [42]. In Netherlands, 70% of the regular people and over 90% of teenagers have a smartphone [43]. The usage of mobile phones represents on average 86 min per day (median 58 min) as proposed by [44]. People use the smartphone even when they are close to the computer [45]. Mobile computing offers the possibility to check the data and gather notifications anytime and anywhere. Real-time notifications provide a reliable method to maintain healthy indoor environment to increase the occupant's health, productivity, and well-being as the building manager can react at time. Consequently, mobile applications were been created in iAQ Mobile, iAQ IoT, iAQ Wi-Fi, and iAirC.

iAQ IoT system incorporates not only wireless communication technologies to interact between iAQ Sensors and iAQ IoT Gateway but also for Internet connection. Therefore, the implementation and installation cost is lower when compared with other solutions that use Ethernet to connect the gateway to the Internet. This solution could easily be designed to use only as many iAQ Sensors as needed due to their modularity and integrates the benefits of the WSN and IoT architectures.

iAQ Wi-Fi and iAirC use cloud service for data storage and data access. The use of cloud service has several advantages referring the cost and security of the storage data.

iAQ Wi-Fi, iAirC, and iDust have benefits both in easy installation and configuration, not only due to the use of wireless technology for communications, but also because they were developed to be compatible with all domestic house devices and not only for smart houses or high-tech houses. These systems are particularly useful for the analysis of IAQ. These functionalities create an easy product installation, which is directly related to IoT concept. The common IAQ supervising architectures should be installed by specialized professional, although the iAQ Wi-Fi, iAirC, and iDust solutions can be installed by the regular people using a gadget with Wi-Fi connectivity, which decrease the costs related to the installation.

Compared to other systems, iAirC and iDust systems incorporate only one sensor, which provides advantages both in ease of installation and configuration due to the use of wireless technology but also due to its small size. These systems use the ESP8266 for both processing and Internet connectivity. This method not only delivers numerous benefits concerning the decrease of the system cost, but also increases the processing power as the ESP8266 has an 80 MHZ CPU, while the Arduino UNO has a 16 MHZ CPU, for example.

#### 5. Conclusions

This chapter has presented several solutions for indoor air quality monitoring and decision-making tools for enhanced healthcare. All the given solutions were developed using open-source technologies, cost-effective sensors, low price of construction, installation, modularity, scalability, and easy access to monitoring data. The results obtained by these solutions are auspicious, as this kind of systems might

#### Indoor Air Quality Monitoring for Enhanced Healthy Buildings DOI: http://dx.doi.org/10.5772/intechopen.81478

be used to provide a detailed stream of data that can be used by the building manager for correct maintenance to offer not only a safe but also a healthy environment for enhanced living environments.

On the one hand, the real-time monitoring is a significant method to support the clinical analysis by medical specialists as the therapeutic team could analyze the history of IAQ conditions of the environment where the patient resides and link these data with his health problems. On the other hand, by supervising IAQ, it is conceivable to identify the poor air quality situations appropriately and plan interventions for enhanced living environments.

The WSN architecture is appropriated to large buildings with no Wi-Fi networks available. However, the IoT architecture is appropriated to domestic homes as the majority provide Wi-Fi access points and also because the easy installation and configuration allows the user to start with a few devices and increase the number of them as he needs.

In the opinion of the authors, the future of air quality monitoring solutions focuses on the development of Wi-Fi systems that incorporate only one sensor. In this way, the user can not only create an ecosystem to suit them by monitoring the parameters he wants, but can also make the systems more cost-effective and easier to install.

As a future work, the proposed solutions should plan software and hardware improvements to fit specific cases such as hospitals, schools, and industry. It is also essential to create secure methods for data sharing between the medical team in order to support clinical diagnostics. The authors believe that in the future, systems like the presented ones will be used as an integral part of the daily human routine in order to provide safe and productive living environments.

### Acknowledgements

solutions aim to offer the support to a medical examination by clinical professionals as the medical team might analyze the history of IAQ parameters collected from the environments where the patient lives and relate these records with his health

An essential advantage of the use of ZigBee communication (iAQ, iAQ Mobile and iAQ IoT) is that we can have many iAQ Sensors collecting indoor air quality data, and only one iAQ Gateway must be connected to the Internet as Zigbee have an indoor RF line-of-sight range up to 50 m. It is essential for some scenarios, in this way, as it is no longer being required for Wi-Fi network coverage throughout all area of hous-

Of about 56% of American adults are now smartphone holders [42]. In Netherlands, 70% of the regular people and over 90% of teenagers have a smartphone [43]. The usage of mobile phones represents on average 86 min per day (median 58 min) as proposed by [44]. People use the smartphone even when they are close to the computer [45]. Mobile computing offers the possibility to check the data and gather notifications anytime and anywhere. Real-time notifications provide a reliable method to maintain healthy indoor environment to increase the occupant's health, productivity, and well-being as the building manager can react at time. Consequently, mobile applications were been created in iAQ Mobile, iAQ IoT, iAQ Wi-Fi,

iAQ IoT system incorporates not only wireless communication technologies to interact between iAQ Sensors and iAQ IoT Gateway but also for Internet connection. Therefore, the implementation and installation cost is lower when compared with other solutions that use Ethernet to connect the gateway to the Internet. This solution could easily be designed to use only as many iAQ Sensors as needed due to their modularity and integrates the benefits of the WSN and IoT architectures.

iAQ Wi-Fi and iAirC use cloud service for data storage and data access. The use of cloud service has several advantages referring the cost and security of the storage data. iAQ Wi-Fi, iAirC, and iDust have benefits both in easy installation and configuration, not only due to the use of wireless technology for communications, but also because they were developed to be compatible with all domestic house devices and not only for smart houses or high-tech houses. These systems are particularly useful for the analysis of IAQ. These functionalities create an easy product installation, which is directly related to IoT concept. The common IAQ supervising architectures should be installed by specialized professional, although the iAQ Wi-Fi, iAirC, and iDust solutions can be installed by the regular people using a gadget with Wi-Fi

Compared to other systems, iAirC and iDust systems incorporate only one sensor, which provides advantages both in ease of installation and configuration due to the use of wireless technology but also due to its small size. These systems use the ESP8266 for both processing and Internet connectivity. This method not only delivers numerous benefits concerning the decrease of the system cost, but also increases the processing power as the ESP8266 has an 80 MHZ CPU, while the

This chapter has presented several solutions for indoor air quality monitoring and decision-making tools for enhanced healthcare. All the given solutions were developed using open-source technologies, cost-effective sensors, low price of construction, installation, modularity, scalability, and easy access to monitoring data. The results obtained by these solutions are auspicious, as this kind of systems might

connectivity, which decrease the costs related to the installation.

Arduino UNO has a 16 MHZ CPU, for example.

5. Conclusions

42

ing and it needs only an Internet connection at the location of iAQ Gateway.

complications.

Indoor Environmental Quality

and iAirC.

The financial support from the Research Unit for Inland Development of the Polytechnic Institute of Guarda is acknowledged.

### Conflict of interest

The authors declare no conflict of interest.

### Author details

Gonçalo Marques and Rui Pitarma\* Unit for Inland Development, Polytechnic Institute of Guarda, Guarda, Portugal

\*Address all correspondence to: rpitarma@ipg.pt

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### References

[1] Seguel JM, Merrill R, Seguel D, Campagna AC. Indoor air quality. American Journal of Lifestyle Medicine. 2016;11(4):284-2895

[2] Bruce N, Perez-Padilla R, Albalak R. Indoor air pollution in developing countries: A major environmental and public health challenge. Bulletin of the World Health Organization. 2000; 78(9):1078-1092

[3] Jafari MJ et al. Association of sick building syndrome with indoor air parameters. Tanaffos. 2015;14(1):55

[4] Capristo C, Romei I, Boner AL. Environmental prevention in atopic eczema dermatitis syndrome (AEDS) and asthma: Avoidance of indoor allergens. Allergy. 2004;59(s78): 53-60

[5] Joshi S. The sick building syndrome. Indian Journal of Occupational and Environmental Medicine. 2008;12(2):61

[6] Ahn K. The role of air pollutants in atopic dermatitis. Journal of Allergy and Clinical Immunology. 2014;134(5): 993-999

[7] Sundell J. On the history of indoor air quality and health. Indoor Air. 2004;14 (s7):51-58

[8] Pitarma R, Lourenço M, Ramos J. Improving occupational health by modelling indoor pollutant distribution. Facilities. 2016;34(5/6):289-301

[9] De Vito S et al. Cooperative 3D air quality assessment with wireless chemical sensing networks. Procedia Engineering. 2011;25:84-87

[10] Preethichandra DMG. Design of a Smart Indoor Air Quality Monitoring Wireless Sensor Network for Assisted Living; 2013. pp. 1306-1310

[11] Yu T-C, Lin C-C. An intelligent wireless sensing and control system to improve indoor air quality: Monitoring, prediction, and preaction. International Journal of Distributed Sensor Networks. 2015;11(8):140978

energy efficiency. In: Rocha Á, Correia AM, Adeli H, Reis LP, Costanzo S, editors. Recent Advances in Information Systems and Technologies. Vol. 570. Cham: Springer International Publishing; 2017. pp. 3-11

DOI: http://dx.doi.org/10.5772/intechopen.81478

Indoor Air Quality Monitoring for Enhanced Healthy Buildings

[28] Hernández-Muñoz JM et al. Smart Cities at the Forefront of the Future Internet. In: Domingue J, Galis A, Gavras A, Zahariadis T, Lambert D, Cleary F, et al., editors. The Future Internet. Vol. 6656. Berlin, Heidelberg: Springer Berlin Heidelberg; 2011.

[29] Pitarma R, Marques G, Ferreira BR. Monitoring indoor air quality for enhanced occupational health. Journal of Medical Systems. 2017;41(2)

[30] Molisch AF et al. IEEE 802.15. 4a channel model-final report. IEEE P802.

[31] Marques G, Pitarma R. Health informatics for indoor air quality monitoring. In: Information Systems and Technologies (CISTI), 2016 11th Iberian Conference on, 2016; pp. 1-6

[32] Marques G, Pitarma R. Smartphone application for enhanced indoor health environments. Journal of Information Systems Engineering & Management.

[33] Marques G, Pitarma R. An indoor monitoring system for ambient assisted living based on internet of things architecture. International Journal of Environmental Research and Public

[34] Marques G, Pitarma R. Monitoring Health Factors in Indoor Living

Environments Using Internet of Things. In: Rocha Á, Correia AM, Adeli H, Reis LP, Costanzo S, editors. Recent Advances in Information Systems and Technologies. Vol. 570. Cham: Springer

International Publishing; 2017.

[35] Marques G, Pitarma R. IAQ

system for enhanced living

evaluation using an IoT CO2 monitoring

environments. In: Rocha Á, Adeli H, Reis LP, Costanzo S, editors. Trends and

Health. 2016;13(11):1152

pp. 447-462

2004;15(04):0662

2016;4(1):9

pp. 785-794

[20] Gubbi J, Buyya R, Marusic S,

[21] Luo J, Chen Y, Tang K, Luo J. Remote monitoring information system and its applications based on the Internet of Things. In: BioMedical Information Engineering, 2009. FBIE 2009. International Conference on

Future. 2009. pp. 482-485

Networks. 2012;1(3):217-253

Technology. 2011;18(2):65-82

Heidelberg; 2011. pp. 431-446

Smart Cities: An Integrative Framework; 2012. pp. 2289-2297

Journal. 2014;1(1):22-32

45

[25] Chourabi H et al. Understanding

[26] Zanella A, Bui N, Castellani A, Vangelista L, Zorzi M. Internet of things for smart cities. IEEE Internet of Things

[27] Batty M et al. Smart cities of the future. The European Physical Journal Special Topics. 2012;214(1):481-518

Palaniswami M. Internet of Things (IoT): A vision, architectural elements, and future directions. Future Generation Computer Systems. 2013;29(7):1645-1660

[22] Swan M. Sensor Mania! The Internet of Things, Wearable Computing, Objective Metrics, and the Quantified Self 2.0. Journal of Sensor and Actuator

[23] Caragliu A, Del Bo C, Nijkamp P. Smart Cities in Europe. Journal of Urban

[24] Schaffers H, Komninos N, Pallot M, Trousse B, Nilsson M, Oliveira A. Smart cities and the future internet: Towards cooperation frameworks for open innovation. In: Domingue J, Galis A, Gavras A, Zahariadis T, Lambert D, Cleary F, et al., editors. The Future Internet. Vol. 6656. Berlin, Heidelberg: Springer Berlin

[12] Al-Haija QA, Al-Qadeeb H, Al-Lwaimi A. Case study: Monitoring of AIR quality in King Faisal University using a microcontroller and WSN. Procedia Computer Science. 2013;21: 517-521

[13] Universal Open Platform and Reference Specification for Ambient Assisted Living. http://www.universaal. org/

[14] UN. Worldpopulationageing: 1950– 2050; 2001. pp. 11-13

[15] Centers for Disease Control and Prevention. The state of aging and health in America 2007. N. A. on an Aging Society; 2007. Available: https:// www.cdc.gov/aging/pdf/saha\_2007.pdf

[16] Koleva P, Tonchev K, Balabanov G, Manolova A, Poulkov V. Challenges in designing and implementation of an effective ambient assisted living system. In: Telecommunication in Modern Satellite, Cable and Broadcasting Services (TELSIKS), 2015 12th International Conference on; 2015. pp. 305-308

[17] Giusto D, editor. The Internet of Things: 20th Tyrrhenian Workshop on Digital Communications. New York: Springer; 2010

[18] Marques G, Pitarma R. Monitoring and Control of the Indoor Environment. In: 2017 12th Iberian Conference on Information Systems and Technologies (CISTI); 2017. pp. 1-6

[19] Marques G, Pitarma R. Monitoring energy consumption system to improve

### Indoor Air Quality Monitoring for Enhanced Healthy Buildings DOI: http://dx.doi.org/10.5772/intechopen.81478

energy efficiency. In: Rocha Á, Correia AM, Adeli H, Reis LP, Costanzo S, editors. Recent Advances in Information Systems and Technologies. Vol. 570. Cham: Springer International Publishing; 2017. pp. 3-11

References

2016;11(4):284-2895

78(9):1078-1092

53-60

993-999

(s7):51-58

44

[1] Seguel JM, Merrill R, Seguel D, Campagna AC. Indoor air quality. American Journal of Lifestyle Medicine.

Indoor Environmental Quality

[11] Yu T-C, Lin C-C. An intelligent wireless sensing and control system to improve indoor air quality: Monitoring, prediction, and preaction. International Journal of Distributed Sensor Networks.

[12] Al-Haija QA, Al-Qadeeb H, Al-Lwaimi A. Case study: Monitoring of AIR quality in King Faisal University using a microcontroller and WSN. Procedia Computer Science. 2013;21:

[13] Universal Open Platform and Reference Specification for Ambient Assisted Living. http://www.universaal.

2050; 2001. pp. 11-13

pp. 305-308

Springer; 2010

(CISTI); 2017. pp. 1-6

[14] UN. Worldpopulationageing: 1950–

[16] Koleva P, Tonchev K, Balabanov G, Manolova A, Poulkov V. Challenges in designing and implementation of an effective ambient assisted living system. In: Telecommunication in Modern Satellite, Cable and Broadcasting Services (TELSIKS), 2015 12th International Conference on; 2015.

[17] Giusto D, editor. The Internet of Things: 20th Tyrrhenian Workshop on Digital Communications. New York:

[18] Marques G, Pitarma R. Monitoring and Control of the Indoor Environment. In: 2017 12th Iberian Conference on Information Systems and Technologies

[19] Marques G, Pitarma R. Monitoring energy consumption system to improve

[15] Centers for Disease Control and Prevention. The state of aging and health in America 2007. N. A. on an Aging Society; 2007. Available: https:// www.cdc.gov/aging/pdf/saha\_2007.pdf

2015;11(8):140978

517-521

org/

[2] Bruce N, Perez-Padilla R, Albalak R. Indoor air pollution in developing countries: A major environmental and public health challenge. Bulletin of the World Health Organization. 2000;

[3] Jafari MJ et al. Association of sick building syndrome with indoor air parameters. Tanaffos. 2015;14(1):55

[4] Capristo C, Romei I, Boner AL. Environmental prevention in atopic eczema dermatitis syndrome (AEDS) and asthma: Avoidance of indoor allergens. Allergy. 2004;59(s78):

[5] Joshi S. The sick building syndrome. Indian Journal of Occupational and Environmental Medicine. 2008;12(2):61

[6] Ahn K. The role of air pollutants in atopic dermatitis. Journal of Allergy and Clinical Immunology. 2014;134(5):

[7] Sundell J. On the history of indoor air quality and health. Indoor Air. 2004;14

[8] Pitarma R, Lourenço M, Ramos J. Improving occupational health by modelling indoor pollutant distribution.

[9] De Vito S et al. Cooperative 3D air quality assessment with wireless chemical sensing networks. Procedia

[10] Preethichandra DMG. Design of a Smart Indoor Air Quality Monitoring Wireless Sensor Network for Assisted

Facilities. 2016;34(5/6):289-301

Engineering. 2011;25:84-87

Living; 2013. pp. 1306-1310

[20] Gubbi J, Buyya R, Marusic S, Palaniswami M. Internet of Things (IoT): A vision, architectural elements, and future directions. Future Generation Computer Systems. 2013;29(7):1645-1660

[21] Luo J, Chen Y, Tang K, Luo J. Remote monitoring information system and its applications based on the Internet of Things. In: BioMedical Information Engineering, 2009. FBIE 2009. International Conference on Future. 2009. pp. 482-485

[22] Swan M. Sensor Mania! The Internet of Things, Wearable Computing, Objective Metrics, and the Quantified Self 2.0. Journal of Sensor and Actuator Networks. 2012;1(3):217-253

[23] Caragliu A, Del Bo C, Nijkamp P. Smart Cities in Europe. Journal of Urban Technology. 2011;18(2):65-82

[24] Schaffers H, Komninos N, Pallot M, Trousse B, Nilsson M, Oliveira A. Smart cities and the future internet: Towards cooperation frameworks for open innovation. In: Domingue J, Galis A, Gavras A, Zahariadis T, Lambert D, Cleary F, et al., editors. The Future Internet. Vol. 6656. Berlin, Heidelberg: Springer Berlin Heidelberg; 2011. pp. 431-446

[25] Chourabi H et al. Understanding Smart Cities: An Integrative Framework; 2012. pp. 2289-2297

[26] Zanella A, Bui N, Castellani A, Vangelista L, Zorzi M. Internet of things for smart cities. IEEE Internet of Things Journal. 2014;1(1):22-32

[27] Batty M et al. Smart cities of the future. The European Physical Journal Special Topics. 2012;214(1):481-518

[28] Hernández-Muñoz JM et al. Smart Cities at the Forefront of the Future Internet. In: Domingue J, Galis A, Gavras A, Zahariadis T, Lambert D, Cleary F, et al., editors. The Future Internet. Vol. 6656. Berlin, Heidelberg: Springer Berlin Heidelberg; 2011. pp. 447-462

[29] Pitarma R, Marques G, Ferreira BR. Monitoring indoor air quality for enhanced occupational health. Journal of Medical Systems. 2017;41(2)

[30] Molisch AF et al. IEEE 802.15. 4a channel model-final report. IEEE P802. 2004;15(04):0662

[31] Marques G, Pitarma R. Health informatics for indoor air quality monitoring. In: Information Systems and Technologies (CISTI), 2016 11th Iberian Conference on, 2016; pp. 1-6

[32] Marques G, Pitarma R. Smartphone application for enhanced indoor health environments. Journal of Information Systems Engineering & Management. 2016;4(1):9

[33] Marques G, Pitarma R. An indoor monitoring system for ambient assisted living based on internet of things architecture. International Journal of Environmental Research and Public Health. 2016;13(11):1152

[34] Marques G, Pitarma R. Monitoring Health Factors in Indoor Living Environments Using Internet of Things. In: Rocha Á, Correia AM, Adeli H, Reis LP, Costanzo S, editors. Recent Advances in Information Systems and Technologies. Vol. 570. Cham: Springer International Publishing; 2017. pp. 785-794

[35] Marques G, Pitarma R. IAQ evaluation using an IoT CO2 monitoring system for enhanced living environments. In: Rocha Á, Adeli H, Reis LP, Costanzo S, editors. Trends and Advances in Information Systems and Technologies. Vol. 746. Cham: Springer International Publishing; 2018. pp. 1169-1177

month field study. IEEE Transactions on Mobile Computing. 2013;12(7): 1417-1427

**47**

**Chapter 4**

**Abstract**

**1. Introduction**

improve their quality of life [1].

Spaces Users

*Naglaa Sami AbdelAziz Mahmoud*

and psychological tool, of most of the interior types.

**Keywords:** lighting design, interior design, lighting scenes for interiors, artificial lighting design, natural lighting design, lighting psychology design

until 1879 where the artificial light bulb started being used commonly.

Illumination, or to be under the light, is a phenomenon that normally happens under the natural light. Every morning, with the sun rising, all its surroundings illuminate. For a long time, natural lighting was the essential tool to see what surrounds us, until the discovery of the fire, which remained the main light source

A long time before civilization, the illumination process was only sustainable, since it used natural resources that occur without human intervention. The natural light does have its regulations as it appears in specific positions, which change over day times. To reach, a particular scene, using natural lighting, several solutions are possible, where some could be classified under sustainable solutions, and scientists along with designers have created new systems repeatedly. The tools that control, both natural and artificial lighting, are diverse but enable the interior lighting designer to create a particular scene that affects positively on spaces' users, to

Like many discoveries, scientific developments, and human creations, the specialization became an urge within any profession. Thus, the interior designer nowadays is much keen to comply with the users' needs, as many details are considered for his well-being, physical and mental health, and his entire safe life experience—as per the declaration of the International Federation of Interior Architects/ Designers (IFI). The architect has his responsibility in the complexity of the buildings' layouts. However, the architect, while interfering in the interior space, as

Best Illumination Scenes for

Can we live in a dark environment? Light is the essential element, natural or artificial, traditional or sustainable, that helps us proceed in our life. Creating lighting scenes is one of the important roles of an interior designer, to create the interior environment for the users, whether in private or public spaces. Designing appropriate lighting to the function, the designer refers to the ideal set design using artificial elements in addition to the possible natural penetration to reach the complete lighting scene, which suits the type of interior function. The lighting design differs from interior type to others, and success of the lighting scene contributes to the success of the full experience of all the places we live. This chapter will explore the possible lighting design that affects positively on the life enhancement, as a physical

[36] Yu T-C et al. Wireless sensor networks for indoor air quality monitoring. Medical Engineering & Physics. 2013;35(2):231-235

[37] Myers SS et al. Increasing CO2 threatens human nutrition. Nature. 2014;510(7503):139-142

[38] Neuburg M. iOS 7 Programming Fundamentals: Objective-c, xcode, and cocoa basics. United States: O'Reilly Media, Inc.; 2013

[39] Lacis AA, Schmidt GA, Rind D, Ruedy RA. Atmospheric CO2: Principal control Knob governing earth's temperature. Science. 2010;330(6002): 356-359

[40] Awbi HB. Ventilation of Buildings. Taylor & Francis; 2003

[41] Marques G, Roque Ferreira C, Pitarma R. A system based on the internet of things for real-time particle monitoring in buildings. International Journal of Environmental Research and Public Health. 2018;15(4):821

[42] Smith A. Pew Research Center. Smartphone Ownership–2013 Update. Vol. 5; 2013

[43] van Deursen AJAM, Bolle CL, Hegner SM, Kommers PAM. Modeling habitual and addictive smartphone behavior. Computers in Human Behavior. 2015;45:411-420

[44] Hintze D, Findling RD, Scholz S, Mayrhofer R. Mobile Device Usage Characteristics: The Effect of Context and Form Factor on Locked and Unlocked Usage; 2014. pp. 105-114

[45] Rahmati A, Zhong L. Studying smartphone usage: Lessons from a four-

### **Chapter 4**

Advances in Information Systems and Technologies. Vol. 746. Cham: Springer month field study. IEEE Transactions on

Mobile Computing. 2013;12(7):

1417-1427

International Publishing; 2018.

Indoor Environmental Quality

[36] Yu T-C et al. Wireless sensor networks for indoor air quality monitoring. Medical Engineering &

[37] Myers SS et al. Increasing CO2 threatens human nutrition. Nature.

[38] Neuburg M. iOS 7 Programming Fundamentals: Objective-c, xcode, and cocoa basics. United States: O'Reilly

[39] Lacis AA, Schmidt GA, Rind D, Ruedy RA. Atmospheric CO2: Principal

temperature. Science. 2010;330(6002):

[40] Awbi HB. Ventilation of Buildings.

[41] Marques G, Roque Ferreira C, Pitarma R. A system based on the internet of things for real-time particle monitoring in buildings. International Journal of Environmental Research and

Public Health. 2018;15(4):821

[42] Smith A. Pew Research Center. Smartphone Ownership–2013 Update.

[43] van Deursen AJAM, Bolle CL, Hegner SM, Kommers PAM. Modeling habitual and addictive smartphone behavior. Computers in Human Behavior. 2015;45:411-420

[44] Hintze D, Findling RD, Scholz S, Mayrhofer R. Mobile Device Usage Characteristics: The Effect of Context and Form Factor on Locked and Unlocked Usage; 2014. pp. 105-114

[45] Rahmati A, Zhong L. Studying smartphone usage: Lessons from a four-

control Knob governing earth's

Taylor & Francis; 2003

Physics. 2013;35(2):231-235

2014;510(7503):139-142

Media, Inc.; 2013

356-359

Vol. 5; 2013

46

pp. 1169-1177
