**5. Air contaminants and their effects upon human health**

The prediction of hazards and risks generated by some building materials is based on a review of the individual chemical components of the whole material, taking into consideration how these components interact between them as well as with other factors like humidity, respiratory gases, etc. For this reason, the safety and health file contains information on each chemical compound from the material composition, the chemistry of the possible reactions which could occur, etc.

The specific behavior upon living creatures and different characterization of pollutants from air determined the literature definition thereof as particulate pollutants and gaseous pollutants. Many terms of science and engineering will be used in this section, without a definition if the words are used consistently with commonly accepted meanings in these fields, and, therefore, could be easily found in professional references. If, however, a term has a unique or different meaning, this will be defined in the text.

Airborne contaminants could be classified according to their nature, following the definitions according to the *Glossary of Fundamentals of Industrial Hygiene* [7]:

## **5.1 Dusts**

*Indoor Environment and Health*

**interactions**

environment from indoor-generated pollutants.

reactions and in tissues and organ damage [7].

and instrumentation; and toxicology [7].

Monitoring of Indoor and Outdoor Air Pollution" [15].

so-called historical data could be used, to a certain extent and in well-defined

while the risk is rather dependent on the exposure time and intensity [7].

that minimize the exposure to airborne pollutants and contaminants [11].

**4. Main types of pollutants in indoor air living spaces and involved** 

The international legislation and local regulations aim to protect the inhabitants and workers from harmful exposures to hazardous substances, as well as the

A classification of the factors causing people discomfort or morbidity could be made by the nature of these factors like chemical, physical, and biological. The route by which the harmful agent enters the body is the key solution to protect people against their harmful action. The chemical and biological contaminants enter the human body usually through inhalation, skin contact, or ingestion. Physical agents (vibration, noise, pressure, temperature, various electromagnetic radiations, etc.) usually act to the whole body and can result in harmful biochemical

The correlation between occupational exposures and worker health is studied by the environmental and occupational medicine, with specialization in industrial hygiene (an interdisciplinary science based on chemical, mechanical, civil, or environmental engineering, chemistry, biology, physics) with tight connections with air pollution; analytical chemistry; engineering; heat, pressure, ergonomics, and other physical factors; ionizing and nonionizing radiation; noise and vibration; personal protective equipment; regulations, standards, and guidelines; sampling

The main types of indoor pollutants are screened below, and methods for their diction were previously published by the authors in "Electrochemical Sensors for

In this light, IAQ is an important part of so-named smart building concept, along with other essential components, such as aesthetical architecture, durability, energy savings, etc. The accomplishment of the performance objectives related to these criteria by using environment-friendly and cost-effective tools contributes to the eco-efficient built environment [13]. More details about the different strategies (e.g., from marketing to technologies, algorithms, and big data) involved in the achievement of a smart eco-efficient built environment are described in [14]. Based on these aspects, the EPA in the USA published on its website a special program, Indoor airPLUS, in order to help the new home builders to improve the quality of indoor air, by defining construction practices and product specifications

The terms hazard and risk, which are used in some situations as synonyms, have in this field quit different significance. A hazard is an object or a set of conditions which can affect the human health or safety and could be extended to plants and animals in the broader context of the environment. The risk is the manifestation of an imminent harmful occurrence, defined quantitatively by a statistical expression or qualitatively via the probability of occurrence. For example, the possibility of harm from many carcinogen hazard facts is low if the exposure to the hazardous substance happens at low intensity and short duration (i.e., the risk is low). In other words, a highly toxic chemical could be out of risk if an efficient barrier is built between the substance potential emission space and the human subject working in the area. In brief, the hazard is given by the intrinsic properties of the contaminant,

conditions, to predict the medical problems for population [7].

**90**

This word is used to designate solid particles generated by diverse mechanical and/or thermal procedures applied during exploitation and/or processing of ores, rocks, wood, and coal. Dusts are the results of advanced fragmentation associated with the above-mentioned types of operations. Generally, dusts are made of particles with high densities; therefore, the particles settle rather easily by gravity and, in most situations, do not flocculate.

### **5.2 Fume**

This name is given for the small particles formed in air by the evaporation of solid materials (the typical case is the metal fume formed during welding). These particles have sizes less than 1 micron and needle-like morphology.

### **5.3 Smoke**

The particles from smoke are generally formed during the combustion or sublimation processes, associated with the local overheating; the particles from smoke are called soot. The smoke cannot be usually avoided when solid carbon-rich fuels are burned (coal, wood, solid waste). In smoke, the dry soot particles are often associated with liquids in complex droplets.

#### **5.4 Vapors**

The term vapors refers to the existence of small amounts of certain substances in gas phase, substances which are, in pure state, solid or liquid at ambient temperature and pressure. When increasing the pressure and/or decreasing the temperature, most vapors transform into solid or liquid state. The vapors spread fast and easy in the air, due to their high diffusion potential associated with the high degree of freedom of moving molecules in the gas phase. Most vapors from the indoor air belong to the volatile organic compound (VOC) class (typical examples are various solvents with low boiling points).

#### **5.5 Aerosols**

The term aerosol refers to particles of 0.01–100 μm (smaller than in smokes or fumes), in liquid or solid phase. The aerosols remain dispersed in air for quite long time and have a high diffusion capacity to the lung alveoli, even when breathing. Some aerosols are beneficial to health, when a medicine is conditioned as aerosol.

#### **5.6 Mists**

Mists are formed sometimes when proper conditions are reached to condense a compound from vapor state to liquid state. The size of the droplets formed is small enough not to be settled as liquid, but remains suspended as small particles. The mists are differentiated from aerosols by the bigger size of the droplets in the first case. Mists are also formed by atomization and splashing in different liquid manipulation technologies.

The effects of the particles on the human health strongly depend on their size and behavior when entering the human body. The fine particles persist in the atmosphere for a few days without sedimentation, so they can be transported over long distances. They can have harmful effects on human health and environment even thousands of kilometers away from the source. The respiratory system supports the strongest attack by small particles. The particles that reach the lungs are fixed on the lung alveoli, reducing the oxygen exchange surface of the lungs. Three types of fractions can be defined [7]:


The risk of particles is due to deposits that occur throughout the respiratory system, from the nose to the alveoli, because the respiratory system is like a channel that branches from the point of inhalation (the nose or mouth) to the pulmonary alveoli with the constant diameter decreasing. As the particle containing air passes through the tracheobronchial tract to the alveoli, the largest particles are progressively stored, followed by smaller particles. The particles with sizes less than 10 μm (PM 10) are deposited on the tracheobronchial tract, and those around 2.5 μm and smaller (PM 2.5) are stored in the lungs. They can readily be absorbed into the blood, causing poisoning or worsening of chronic respiratory diseases [7].

#### **5.7 Gas**

Gas is a state of matter characterized by materials with very low density and viscosity, expanding or contracting upon temperature and pressure changes. The gases easily diffused are distributed uniformly in any container. The gases are characterized by weak interactions between the molecules and a strong extent of freedom in moving of the molecules contained. Some gas species from the lower atmosphere layers can diffuse to the upper layers (troposphere), where they can occur chemical reactions influencing the overall atmosphere quality.

**93**

*Indoor Air Pollutants and the Future Perspectives for Living Space Design*

by several organizations in different countries [7, 13].

number of Volatile Organic Compounds (VOCs) could be mentioned.

Among the gaseous contaminants of the indoor air, the nitrogen and sulfur oxides, hydrogen sulfide, carbon monoxide, carbon dioxide, as well as a large

retards breathing, and generates discomfort. At long exposure at low concentrations, it was found that pollution from sulfur dioxide and sulfates may cause a higher incidence of colon and breast cancers. In the upper respiratory system, SO2 can cause lung edema or even death. The main sources of sulfur compounds in the atmosphere are the volcanic eruptions, the bacterial reactions in swamps, the marine phytoplankton reactions, burning of fossil fuels, and sulfide burning to produce SO2 in the production of sulfuric acid. Traces of SO2 result from the fuel burning, especially in diesel engines. In wet air and in the presence of UV radiation from the sun, sulfur dioxide transforms into sulfuric acid, which has a remarkable ability to associate the

soot particles, generating a very toxic and stable smoke named smog [16].

ant odor (as rotten eggs) and a quite acidic character [16].

tions may be fatal [16].

solid (dry ice) [18].

reduces the ability to concentrate [17].

*Hydrogen sulfide* results mainly from the urban wastewater treatment and from the spontaneous decomposition of swamp vegetation. This gas has a very unpleas-

*Nitrogen oxides.* The main oxides of nitrogen from the air are nitrogen monoxide (NO) and nitrogen dioxide. Nitrogen monoxide is a colorless and odorless gas, while nitrogen dioxide is a brownish-red gas with a strong, sulfurous odor. In combination with airborne particles, NO2 forms a brown-red mist that, in the presence of sunlight, forms photochemical oxidants. Nitrogen dioxide is a highly toxic gas for both humans and animals because of its oxidizing effect; the degree of toxicity of nitrogen dioxide is four times higher than that of nitrogen monoxide. Short-term exposure to these pollutants causes respiratory difficulties, respiratory irritation, and lung dysfunctions. Long-term exposure at a low concentration may destroy the lung tissue, resulting in pulmonary emphysema, and exposure to high concentra-

*Carbon monoxide* is a colorless, odorless, and insipid gas of natural or anthropogenic provenience. The anthropogenic activities responsible for CO generation are the different processes of incomplete combustion of fossil fuels, in both highcapacity thermoelectric power plants and small domestic heating plants, as well as the combustion of fuels in internal combustion engines and chemical processes occurring in the production of iron and steel and in oil refining. CO is a very toxic gas for humans and animals, being lethal at concentrations of about 100 mg/m3

reducing the oxygen transport capacity in the blood. At relatively low concentrations, it affects the central nervous system, weakens the heart rate, decreases the volume of blood distributed in the body; reduces the visual acuity and physical capacity; generates acute fatigue, breathing difficulties, irritability, migraines, rapid breathing, lack of coordination, nausea, dizziness, and confusion; and

*Carbon dioxide* is the normal product of fuel combustion from the power plants, as well as from the respiratory processes of the living creatures. In ambient conditions, carbon dioxide is a colorless, odorless, slightly acidic, and non-flammable gas. Upon compression and temperature decrease, CO2 transforms into a liquid or a

Carbon dioxide is not what is called a toxic gas, but its concentration indoor is an indicator of a good, breathable healthy air. The normal outdoor CO2 concentration is of 250–350 ppm, while indoor air of good quality can reach 1000 ppm. After this limit, the CO2 levels begin to influence the health condition of humans: up to

, by

Due to their health-associated issues, such indoor air contaminants are regulated

*Sulfur dioxide* is a colorless gas with a pungent, irritating odor that causes tearing,

*DOI: http://dx.doi.org/10.5772/intechopen.87309*

#### *Indoor Air Pollutants and the Future Perspectives for Living Space Design DOI: http://dx.doi.org/10.5772/intechopen.87309*

*Indoor Environment and Health*

manipulation technologies.

fractions can be defined [7]:

nostrils and mouth

alveolar region

The term aerosol refers to particles of 0.01–100 μm (smaller than in smokes or fumes), in liquid or solid phase. The aerosols remain dispersed in air for quite long time and have a high diffusion capacity to the lung alveoli, even when breathing. Some aerosols are beneficial to health, when a medicine is conditioned as aerosol.

Mists are formed sometimes when proper conditions are reached to condense a compound from vapor state to liquid state. The size of the droplets formed is small enough not to be settled as liquid, but remains suspended as small particles. The mists are differentiated from aerosols by the bigger size of the droplets in the first case. Mists are also formed by atomization and splashing in different liquid

The effects of the particles on the human health strongly depend on their size and behavior when entering the human body. The fine particles persist in the atmosphere for a few days without sedimentation, so they can be transported over long distances. They can have harmful effects on human health and environment even thousands of kilometers away from the source. The respiratory system supports the strongest attack by small particles. The particles that reach the lungs are fixed on the lung alveoli, reducing the oxygen exchange surface of the lungs. Three types of

• The inhalable fraction, which includes all the particles that can enter the

• The respirable fraction, which includes small particles that can reach the

The risk of particles is due to deposits that occur throughout the respiratory system, from the nose to the alveoli, because the respiratory system is like a channel that branches from the point of inhalation (the nose or mouth) to the pulmonary alveoli with the constant diameter decreasing. As the particle containing air passes through the tracheobronchial tract to the alveoli, the largest particles are progressively stored, followed by smaller particles. The particles with sizes less than 10 μm (PM 10) are deposited on the tracheobronchial tract, and those around 2.5 μm and smaller (PM 2.5) are stored in the lungs. They can readily be absorbed into the blood, causing poisoning or worsening of chronic respiratory diseases [7].

Gas is a state of matter characterized by materials with very low density and viscosity, expanding or contracting upon temperature and pressure changes. The gases easily diffused are distributed uniformly in any container. The gases are characterized by weak interactions between the molecules and a strong extent of freedom in moving of the molecules contained. Some gas species from the lower atmosphere layers can diffuse to the upper layers (troposphere), where they can occur chemical

and enter the tracheobronchial region during inhalation

reactions influencing the overall atmosphere quality.

• The thoracic fracture, which includes particles that can pass through the larynx

**5.5 Aerosols**

**5.6 Mists**

**92**

**5.7 Gas**

Among the gaseous contaminants of the indoor air, the nitrogen and sulfur oxides, hydrogen sulfide, carbon monoxide, carbon dioxide, as well as a large number of Volatile Organic Compounds (VOCs) could be mentioned.

Due to their health-associated issues, such indoor air contaminants are regulated by several organizations in different countries [7, 13].

*Sulfur dioxide* is a colorless gas with a pungent, irritating odor that causes tearing, retards breathing, and generates discomfort. At long exposure at low concentrations, it was found that pollution from sulfur dioxide and sulfates may cause a higher incidence of colon and breast cancers. In the upper respiratory system, SO2 can cause lung edema or even death. The main sources of sulfur compounds in the atmosphere are the volcanic eruptions, the bacterial reactions in swamps, the marine phytoplankton reactions, burning of fossil fuels, and sulfide burning to produce SO2 in the production of sulfuric acid. Traces of SO2 result from the fuel burning, especially in diesel engines. In wet air and in the presence of UV radiation from the sun, sulfur dioxide transforms into sulfuric acid, which has a remarkable ability to associate the soot particles, generating a very toxic and stable smoke named smog [16].

*Hydrogen sulfide* results mainly from the urban wastewater treatment and from the spontaneous decomposition of swamp vegetation. This gas has a very unpleasant odor (as rotten eggs) and a quite acidic character [16].

*Nitrogen oxides.* The main oxides of nitrogen from the air are nitrogen monoxide (NO) and nitrogen dioxide. Nitrogen monoxide is a colorless and odorless gas, while nitrogen dioxide is a brownish-red gas with a strong, sulfurous odor. In combination with airborne particles, NO2 forms a brown-red mist that, in the presence of sunlight, forms photochemical oxidants. Nitrogen dioxide is a highly toxic gas for both humans and animals because of its oxidizing effect; the degree of toxicity of nitrogen dioxide is four times higher than that of nitrogen monoxide. Short-term exposure to these pollutants causes respiratory difficulties, respiratory irritation, and lung dysfunctions. Long-term exposure at a low concentration may destroy the lung tissue, resulting in pulmonary emphysema, and exposure to high concentrations may be fatal [16].

*Carbon monoxide* is a colorless, odorless, and insipid gas of natural or anthropogenic provenience. The anthropogenic activities responsible for CO generation are the different processes of incomplete combustion of fossil fuels, in both highcapacity thermoelectric power plants and small domestic heating plants, as well as the combustion of fuels in internal combustion engines and chemical processes occurring in the production of iron and steel and in oil refining. CO is a very toxic gas for humans and animals, being lethal at concentrations of about 100 mg/m3 , by reducing the oxygen transport capacity in the blood. At relatively low concentrations, it affects the central nervous system, weakens the heart rate, decreases the volume of blood distributed in the body; reduces the visual acuity and physical capacity; generates acute fatigue, breathing difficulties, irritability, migraines, rapid breathing, lack of coordination, nausea, dizziness, and confusion; and reduces the ability to concentrate [17].

*Carbon dioxide* is the normal product of fuel combustion from the power plants, as well as from the respiratory processes of the living creatures. In ambient conditions, carbon dioxide is a colorless, odorless, slightly acidic, and non-flammable gas. Upon compression and temperature decrease, CO2 transforms into a liquid or a solid (dry ice) [18].

Carbon dioxide is not what is called a toxic gas, but its concentration indoor is an indicator of a good, breathable healthy air. The normal outdoor CO2 concentration is of 250–350 ppm, while indoor air of good quality can reach 1000 ppm. After this limit, the CO2 levels begin to influence the health condition of humans: up to

2000 ppm, the sensation of poor air combines with sleepiness, between 2000 and 5000 ppm; the symptoms are drowsiness, headaches, loss of attention, and even nausea or increased heart rate. Over 5000 ppm, CO2 could be considered a potential toxic gas, and the oxygen deprivation appears [19].

Particularly, space maximum allowable concentration of CO2 is 10,000 ppm [2].

The *VOCs* are a numerous class of organic compounds, with small- or mediumsized molecules, present indoor especially from the construction and decorating materials, as paints, varnishes, and wax; hygiene; and beauty products for cleaning/ disinfecting, degreasing, personal care, and hobby products. Commonly, the levels of the most usual VOCs are several times higher inside homes than outside, even for homes located in rural or in highly industrial areas. A characteristic of the VOCs indoor is the fact that the exposure to elevated concentrations can persist in the air long after the activity generating the chemicals had finished [20].

Among the most common VOCs, formaldehyde, aromatic and aliphatic hydrocarbons, carbonyl compounds, as well as chlorinated organic compounds are widely spread indoor [20].

*Formaldehyde* is one of the most common VOCs. It is a colorless gas with a sharp smell. The sources of formaldehyde indoor are lots of building and finishing materials: plywood, particleboard, glues, waterproof fabrics, foams, and fuel burning [21].

It should be noted that formaldehyde is one of the most toxic indoor air pollutants [13] and its high presence probability indoors due to the above-mentioned sources suggests the need of action in the direction of source-reduction measure implementation.

The main *aromatic*, *naphthenic*, *and aliphatic hydrocarbons* cited to be present in the indoor air, especially in the car interiors, are: benzene; toluene; ethylbenzene; xylenes; styrene; propyl-benzene; cumene; ethyl-methyl-benzenes; trimethylbenzenes; naphthalene; methylcyclopentane; 1,2-dimethylcyclopentane; cyclohexane; dimethylcyclopentane cis- and trans-1,2-dimethylcyclopentane; methylcyclohexane; ethylcyclopentane; 1,4-dimethylcyclohexane; trimethylcyclohexanes; propylcyclohexane; methyl-propyl-cyclohexanes; hexane; 3,3-dimethylpentane; 2-methylhexane; 2,3-dimethylpentane; 3-methylhexane; 3-ethylpentane; heptane; dimethylhexanes; 2-methylheptane; octane; 2,5-dimethylheptane; 3-methyloctane; 2,6-dimethyloctane; 2-methylnonane; decane; undecane; dodecane; tridecane; tetradecane; and pentadecane.

Methylene chloride (dichloromethane), benzyl chloride, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, p-dichlorobenzene, and 1,1,1-trichloroethane used together with polybrominated diphenyl ethers, hexabromocyclododecanes, tetrabromobisphenol A, and polybrominated biphenyls are some examples of *halogenated compounds* used in plastic materials to improve their technical performance or act as flame retardants [7, 10].

*Radon* is a radioactive, colorless, odorless, and tasteless gas [22] which occurs naturally as an intermediate step in the normal radioactive decay chains of thorium and uranium. These last elements are often found in the composition of construction materials (i.e., bricks, ceramic tiles, cement, etc.), and therefore the buildings made from these materials could accumulate in time (if the ventilation system is not appropriate) a huge amount of this radioactive gas with dangerous action for human health [23].

#### **6. Conclusions**

In order to better understand and control IAQ problems in living spaces, some general aspects related to chemical and particle content of air, with practical

**95**

**Author details**

University of Iasi, Iasi, Romania

University of Iasi, Iasi, Romania

provided the original work is properly cited.

University, Iasi, Romania

\*, Dorina Nicolina Isopescu2

157/2017, financed by Romanian Space Agency (ROSA).

1 Department of Environmental Engineering and Management, Faculty of

\*Address all correspondence to: icre1@yahoo.co.uk and doilub@uaic.ro

Chemical Engineering and Environmental Protection, "Gheorghe Asachi" Technical

2 Faculty of Civil Engineering and Building Services, "Gheorghe Asachi" Technical

3 Department of Material Chemistry, Faculty of Chemistry, "Alexandru Ioan Cuza"

© 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,

, Doina Lutic3

\* and Gabriela Soreanu1

Igor Cretescu1

*Indoor Air Pollutants and the Future Perspectives for Living Space Design*

advices, specific terminology including links to standards and regulations, were

Main types of pollutants in indoor air living spaces and their effects upon human

In order to point out the importance of IAQ for everyone's health but especially to those that have chronic respiratory problems, a governmental program, namely, Indoor airPLUS, was launched in the USA, on the EPA website, consisting in a voluntary partnership and labeling actions that helps new home builders to improve the quality of indoor air by requiring construction practices and product specifica-

This work was partially supported by the following projects: EFECON, Ecoinnovative Products and Technologies for Energy Efficiency in Construction; POC/71/1/4, Knowledge Transfer Partnership, Cod MySMIS: 105524, ID: P\_40\_295,

Project co-financed by the European Regional Development Fund; and RDI Program for Space Technology and Advanced Research (STAR), project no.

Monitoring methodology and remediation of IAQ were also reviewed.

tions that minimize exposure to airborne pollutants and contaminants.

*DOI: http://dx.doi.org/10.5772/intechopen.87309*

presented in this chapter.

health were presented.

**Acknowledgements**

*Indoor Air Pollutants and the Future Perspectives for Living Space Design DOI: http://dx.doi.org/10.5772/intechopen.87309*

advices, specific terminology including links to standards and regulations, were presented in this chapter.

Monitoring methodology and remediation of IAQ were also reviewed.

Main types of pollutants in indoor air living spaces and their effects upon human health were presented.

In order to point out the importance of IAQ for everyone's health but especially to those that have chronic respiratory problems, a governmental program, namely, Indoor airPLUS, was launched in the USA, on the EPA website, consisting in a voluntary partnership and labeling actions that helps new home builders to improve the quality of indoor air by requiring construction practices and product specifications that minimize exposure to airborne pollutants and contaminants.
