**2. Indoor environment**

## **2.1. Basic metrics of the indoor environment**

Indoor Environmental Quality (IEQ) is a complex term in the field of indoor climate engineer‐ ing, which reflects the combined impact of the different characteristics of the indoor environ‐ ment on the basic senses of the human body. Figure 1 summarizes the basic metrics of the IEQ: Indoor Air Quality (IAQ), Indoor Thermal Quality (ITQ), Indoor Lighting Quality (ILQ), Indoor Sound Quality (ISQ), Indoor Odor Quality (IOQ), and Indoor Vibration Quality (IVQ). Textile and particularly non-woven textiles may contribute to all these characteristics of the indoor environment.

The review article [4] discusses the difficulty to assess which of the basic metrics and particular characteristics of the indoor environment plays the most important role for the quality of life and work of the inhabitants. The authors attribute that fact to concomitant problems of investigations cited in their work: problems with the studies' settings, the percentage of respondents, or the analysis of the data obtained.

A later study [5], however, has already reported such results. According to their analysis, the *five* main characteristics of the IEQ, which are important for the occupants (taken as absolute values of the regression coefficients for positive/negative effects) are:


**Figure 1.** Basic metrics of the Indoor Environmental Quality (IEQ)

**•** Noise level

Non-woven textiles are an important part of textiles in the indoor environment. Different groups of non-woven materials can be found in buildings and means of transport: floor coverings, wallcoverings, upholstery and furniture textiles, filters, etc. Depending on their

**•** *Hidden non-woven textiles* as part of clothing, bedding, furniture, and heating, ventilation,

**•** *Visible non-woven textiles* as part of floor coverings, wallcoverings, and furniture systems. The purpose of the chapter is to discuss the application of non-wovens indoors from the point of view of the basic metrics of the indoor environment used to assess the quality of living and working. Different types of applications are considered: non-woven textiles, used as floor coverings, bedding, furniture, wallcoverings, walls, and curtains, as well as non-woven textiles, applied in cars. The influence of the non-woven materials on Indoor Air Quality (IAQ), Indoor Thermal Quality (ITQ), Indoor Lighting Quality (ILQ), Indoor Sound Quality (ISQ), Indoor Odor Quality (IOQ), and Indoor Vibration Quality (IVQ) is presented. The risk factors, related with the use of non-wovens indoors and their possible role as sources of pollutants are

Indoor Environmental Quality (IEQ) is a complex term in the field of indoor climate engineer‐ ing, which reflects the combined impact of the different characteristics of the indoor environ‐ ment on the basic senses of the human body. Figure 1 summarizes the basic metrics of the IEQ: Indoor Air Quality (IAQ), Indoor Thermal Quality (ITQ), Indoor Lighting Quality (ILQ), Indoor Sound Quality (ISQ), Indoor Odor Quality (IOQ), and Indoor Vibration Quality (IVQ). Textile and particularly non-woven textiles may contribute to all these characteristics of the

The review article [4] discusses the difficulty to assess which of the basic metrics and particular characteristics of the indoor environment plays the most important role for the quality of life and work of the inhabitants. The authors attribute that fact to concomitant problems of investigations cited in their work: problems with the studies' settings, the percentage of

A later study [5], however, has already reported such results. According to their analysis, the *five* main characteristics of the IEQ, which are important for the occupants (taken as absolute

application, they can be classified as:

also detailed.

188 Non-woven Fabrics

**2. Indoor environment**

indoor environment.

**•** Amount of space

**•** Visual privacy

**2.1. Basic metrics of the indoor environment**

respondents, or the analysis of the data obtained.

values of the regression coefficients for positive/negative effects) are:

and air-conditioning (HVAC) systems;


The first two characteristics are related with the ergonomics of the working and living environment, but at the same time they influence basic metrics of the IEQ like Indoor Air Quality (IAQ). Noise level contributes to Indoor Sound Quality (ISQ). The last two character‐ istics are also related with the ergonomics, but at the same time they are relevant to Indoor Thermal Quality (ITQ), Indoor Lighting Quality (ILQ), and Indoor Sound Quality (ISQ).

Non-woven textiles in the indoor environment can contribute to the amount of space and visual privacy being used as freestanding constructions that divide the indoor space into smaller areas. Non-wovens, as all textile materials, decrease the noise in the built environment and car compartments. All visible non-woven textiles (floor coverings, wallcoverings, upholstery textiles, etc.) influence people's comfort through their colors and textures. At the same time, both visible and hidden non-woven textiles in furniture systems, car seats and compartments influence the comfort of people, which is related to furnishing convenience.

#### **2.2. Human comfort in the indoor environment**

Comfort is a relative and subjective category, but when it is associated with the interaction between the human body and textiles it can be considered as physical, physiological, and psychological comfort. Figure 2 summarizes the main factors related to textiles and clothing, which define human comfort in the indoor environment.

The *physical comfort* is largely a subjective factor: although influenced by receptors that are common to the human body, individuals have varying degrees of sensitivity. The physical

**Figure 2.** Factors that determine human comfort in the indoor environment, related to textiles and clothing

comfort is preconditioned by the contact between the human skin and the textiles, the presence of odors and the stimuli for the eyes. Ensuring physical comfort is a task of both the engineering aspect and the design aspect of the textiles production.

The *physiological comfort*, though again dependent on individual reactions and perceptions, is preconditioned to a high degree by the textiles design and engineering: from the selection of materials and structures, through their production and finishing, to their incorporation in the indoor environment as single items (floor covering, curtains) or parts of complex structures (bedding, furniture). It is predetermined mainly by the sensors for warmth/cold in the body, which are susceptible to thermal environment, presence of room airflow (draft), temperature asymmetry, etc.

The *psychological comfort* – not less subjective – depends largely on the textile design, fashion trends, and other factors, mainly related to art.

## **2.3. Risk factors in the indoor environment**

The concept of Sick Building Syndrome (SBS) was developed in the 1970s. Nowadays, it is associated with the negative attributes of the Indoor Environmental Quality (IEQ). The SBS concept summarizes the dissatisfaction of the occupants from IEQ and series of clinical complaints, related to the stay of people in buildings. However, traditional clinical studies have not completely identified the causes of those complaints. Female subjects and elderly people are more sensitive to IEQ, but the mechanisms by which such sensitivity occurs, remain unspecified enough [6]. SBS is still a subject of clinical, chemical, and engineering studies; for the past decades, significant knowledge about the factors that determine SBS has been accumulated.

The main risk factors, related to indoor air quality (IAQ), which can provoke dissatisfaction among the inhabitants have been summarized in [7]. The results from that research are visually presented in Figure 3.

**Figure 3.** Risk factors for IAQ: summary of data from [7]

Textiles are among the risk factors for the quality of the indoor environment. Their influence on the IEQ is related with the ability of the textile surfaces to accumulate dust and odors, to emit dust and odors, to play the role of insulation layer thus affecting the thermal environment, to have influence upon the acoustics and lighting, etc. The type of the textiles macrostructure: woven, non-woven, or knitted, is also very important, as it determines the application of the particular textile in the indoor environment and its possible contribution to the IEQ.

## **2.4. Pollutants in the indoor environment**

The up-to-date knowledge on the airborne pollutants in the indoor environment differentiates between the following pollutants of the indoor environment:


comfort is preconditioned by the contact between the human skin and the textiles, the presence of odors and the stimuli for the eyes. Ensuring physical comfort is a task of both the engineering

**Figure 2.** Factors that determine human comfort in the indoor environment, related to textiles and clothing

The *physiological comfort*, though again dependent on individual reactions and perceptions, is preconditioned to a high degree by the textiles design and engineering: from the selection of materials and structures, through their production and finishing, to their incorporation in the indoor environment as single items (floor covering, curtains) or parts of complex structures (bedding, furniture). It is predetermined mainly by the sensors for warmth/cold in the body, which are susceptible to thermal environment, presence of room airflow (draft), temperature

The *psychological comfort* – not less subjective – depends largely on the textile design, fashion

The concept of Sick Building Syndrome (SBS) was developed in the 1970s. Nowadays, it is associated with the negative attributes of the Indoor Environmental Quality (IEQ). The SBS concept summarizes the dissatisfaction of the occupants from IEQ and series of clinical complaints, related to the stay of people in buildings. However, traditional clinical studies have not completely identified the causes of those complaints. Female subjects and elderly people are more sensitive to IEQ, but the mechanisms by which such sensitivity occurs, remain unspecified enough [6]. SBS is still a subject of clinical, chemical, and engineering studies; for the past decades, significant knowledge about the factors that determine SBS has been

The main risk factors, related to indoor air quality (IAQ), which can provoke dissatisfaction among the inhabitants have been summarized in [7]. The results from that research are visually

aspect and the design aspect of the textiles production.

trends, and other factors, mainly related to art.

**2.3. Risk factors in the indoor environment**

asymmetry, etc.

190 Non-woven Fabrics

accumulated.

presented in Figure 3.


Volatile Organic Compounds (VOCs) (formaldehyde, pesticides, ingredients of paints, dyes, etc.) are the most widely discussed pollutants that impair indoor air quality [7-9]. The highest levels of VOCs emissions indoors are measured immediately after building finishing or installation of furniture, flooring, etc. Due to their absorption ability textiles should not be installed in the indoor environment during the intensive release of VOCs from other items.The period of VOCs emissions can last from days to months, depending mainly on ventilation (natural or HVAC system), temperature, and humidity [10].

Semi-Volatile Organic Compounds (SVOCs) are associated with the presence of phthalates, pesticides, and flame retardants, which can be frequently found on textile surfaces in the indoor environment [11]. Microbial volatile organic compounds (MVOCs) are formed in the metab‐ olism of fungi and bacteria [12]; therefore, they can be found in the indoor environment due to presence of moisture and mold growth.

A recent work [13] has summarized the state of the art in the field of the Very Volatile Organic Compounds (VVOCs) – an important subgroup of indoor pollutants that involves a wide spectrum of chemical substances. However, there is still no clear definition of VVOCs and techniques for their assessment.
