**4. Evaluation of indoor air pollution and comparison with the urban and high-risk sites**

Clean air is a fundamental health determinant. The quality of indoor air (e.g., homes, offices, schools, day care centres, public buildings, where people spend a large part of their life). Hazardous substances emitted from buildings, construction materials, and indoor equipment or due to all human activities indoors lead to a broad range of health problems and may even be fatal for infants and children. Indoor environmental issues are still an open topic of public health, including health risks and the means by which human exposures can be reduced [38].

Mistakes of evaluation or unacknowledged by public about health risks associated with a variety of indoor environmental pollutants and sources of pollution (e.g., radon, mold and moisture, secondhand smoke, and indoor wood smoke) cause a minor efficacy of prevention and/or risk's low perception. In poorly ventilated dwellings, smoke in and around the house can exceed acceptable levels for fine particles 100-fold [39] with respect to outdoor levels already known. In fact, inadequate ventilation can increase indoor pollutant levels for incomplete dilution of these. High temperature and humidity levels can also increase concen‐ trations of certain pollutants [40]. Outdoor air enters and leaves a house by infiltration, natural ventilation, and mechanical ventilation. If infiltration, natural ventilation, or mechanical ventilation is poor, the air exchange rate is low and pollutant levels can increase rapidly [41].

There are several sources of indoor air pollution including combustion of oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deterio‐ rated, asbestos-containing insulation, wet or damp carpet, cabinetry and objects made with certain pressed wood products (e.g., formaldehyde, pesticides, etc.); products for household cleaning and their maintenance (phtalates, bisphenol A, fragrances, pesticides, detergents, chlorine bleach, lye, ammonia, etc.), cosmetics for personal care (solvents, phtalates, bisphenol A, fragrances, mineral oil, ethoxylated surfactants and 1,4-dioxane, formaldehyde, lead, oxybenzone, parabens, toluene, triclosan, etc.), chemicals used for hobbies (solvents, lead, pesticides, mineral oil, cadmium, manganese dioxide, cobalt, formaldehyde, aromatic and chlorinated hydrocarbons, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, etc); central heating and cooling systems and humidification devices (mold, viruses, fungi, bacteria, mycotoxins, etc.); and outdoor sources such as radon, pesticides, and outdoor air pollution likely to come into the house where can concentrate. Some of these sources (building materials, outdoor sources, wood furnishings, etc.) release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently, and their concentrations can remain in the domestic air for long periods after these activities. The relative importance of any single source depends on how much of a given pollutant it emits and by the proven hazard of those emissions. In some cases, factors such as how old the source is and whether it is properly maintained are very significant (e.g., an improperly functioning gas stove can emit more CO than one that is properly adjusted).

Exposure to indoor air pollution is particularly high among women and young children who spend the most time in the domestic environment, and health effects may be shown soon after exposure or years later.

According to WHO, 4.3 million people a year die from the exposure to household air pollution [39]. In fact, especially cooking and heating with solid fuels (wood, charcoal, etc.) produce high levels of smoke both in and around the home and this contains a large variety of healthdamaging pollutants [42].

Immediate effects such as irritation of the eyes, nose, and throat; headaches; dizziness; and fatigue may show up after a single acute exposure or repeated sub acute exposures. These are usually treatable and have short-term effects. Oftentimes, the simple elimination of a person's exposure to the identified source of pollution is sufficient for restoring health.

An additional problem is the recurrent multiple indoor pollution exposure of residents, complicating and amplifying the health effects [43].

Exposure to indoor air pollution leads to a wide range of respiratory diseases [39, 44] such as lung cancer [45, 46], ischemic heart disease [46], stroke [46], and cataract [46].

There is emerging evidence, although based on fewer studies, that suggests that household air pollution, especially in developing countries, may also increase the risk of other important child and adult illnesses such as the following:


or due to all human activities indoors lead to a broad range of health problems and may even be fatal for infants and children. Indoor environmental issues are still an open topic of public health, including health risks and the means by which human exposures can be reduced [38].

Mistakes of evaluation or unacknowledged by public about health risks associated with a variety of indoor environmental pollutants and sources of pollution (e.g., radon, mold and moisture, secondhand smoke, and indoor wood smoke) cause a minor efficacy of prevention and/or risk's low perception. In poorly ventilated dwellings, smoke in and around the house can exceed acceptable levels for fine particles 100-fold [39] with respect to outdoor levels already known. In fact, inadequate ventilation can increase indoor pollutant levels for incomplete dilution of these. High temperature and humidity levels can also increase concen‐ trations of certain pollutants [40]. Outdoor air enters and leaves a house by infiltration, natural ventilation, and mechanical ventilation. If infiltration, natural ventilation, or mechanical ventilation is poor, the air exchange rate is low and pollutant levels can increase rapidly [41].

There are several sources of indoor air pollution including combustion of oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deterio‐ rated, asbestos-containing insulation, wet or damp carpet, cabinetry and objects made with certain pressed wood products (e.g., formaldehyde, pesticides, etc.); products for household cleaning and their maintenance (phtalates, bisphenol A, fragrances, pesticides, detergents, chlorine bleach, lye, ammonia, etc.), cosmetics for personal care (solvents, phtalates, bisphenol A, fragrances, mineral oil, ethoxylated surfactants and 1,4-dioxane, formaldehyde, lead, oxybenzone, parabens, toluene, triclosan, etc.), chemicals used for hobbies (solvents, lead, pesticides, mineral oil, cadmium, manganese dioxide, cobalt, formaldehyde, aromatic and chlorinated hydrocarbons, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, etc); central heating and cooling systems and humidification devices (mold, viruses, fungi, bacteria, mycotoxins, etc.); and outdoor sources such as radon, pesticides, and outdoor air pollution likely to come into the house where can concentrate. Some of these sources (building materials, outdoor sources, wood furnishings, etc.) release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently, and their concentrations can remain in the domestic air for long periods after these activities. The relative importance of any single source depends on how much of a given pollutant it emits and by the proven hazard of those emissions. In some cases, factors such as how old the source is and whether it is properly maintained are very significant (e.g., an improperly functioning gas stove can emit more CO than one that is properly adjusted).

Exposure to indoor air pollution is particularly high among women and young children who spend the most time in the domestic environment, and health effects may be shown soon after

According to WHO, 4.3 million people a year die from the exposure to household air pollution [39]. In fact, especially cooking and heating with solid fuels (wood, charcoal, etc.) produce high levels of smoke both in and around the home and this contains a large variety of health-

exposure or years later.

430 Current Air Quality Issues

damaging pollutants [42].


Also exposure to unhealthy concentrations of fine PM has been connected to increased respiratory/cardiovascular illnesses [39, 47]. In fact, the smaller air particles can penetrate into the deeper lung. PM is being linked to adverse birth outcomes [46], neurodevelopment, cognitive function [48], and diabetes [39].

Semple et al. [49] said that median PM2.5 concentrations from 93 smoking homes were 31 µg/m3 (ranged between 10 and 111 µg/m3 ) and 3 µg/m3 (ranged between 2 and 6.5) µg/m3 for the 17 non-smoking homes and still showed that non-smokers living with smokers typically have average PM2.5 exposure levels more than three times higher than the WHO guidance for annual exposure to PM2.5 (10 µg/m3 ). So, PM2.5 pollution in indoor ambient where smokers live is approximately 10 times higher than that of non-smoking. A non-smoker living with a smoker is exposed to same PM2.5 of a non-smoker living in a heavily polluted city such as Beijing. This condition is likely to be greatest and dangerous for the very young and for older members of the population because they typically spend more time at home. Zhou and colleagues [50] have demonstrated that in New York City, despite the ban on tobacco smoking, some hookah bars still serve tobacco-based hookahs, and in these particular indoor environments, the authors have found elevated concentrations of pollutants that may present a real health threat to visitors and employees. The mean real-time PM2.5 level was 1179.9 µg/m3 , whereas the filterbased total PM mean was 691.3 µg/m3 . The mean real-time black carbon level was 4.1 µg/m3 , organic carbon was 237.9 µg/m3 , and CO was 32 ppm. Airborne nicotine was present in all studied hookah bars (4.2 µg/m3 ).

Dorizas et al. [51] with their study showed that in nine naturally ventilated primary schools of Athens (Greece) during spring, PM concentrations were significantly affected by the ventilation rates and presence of students. Both PM10 and PM2.5 were greater during teaching than the non-teaching hours, and, in many cases, the PM2.5 concentrations exceeded their limit values. For most of the cases, the indoor to outdoor concentrations ratios of PM10 and PM2.5 were much greater than one, indicating that the indoor environment was being mostly affected by indoor sources instead of the outdoor air. Furthermore, it was found that chalk and marker board usage significantly affects indoor pollutant concentrations.

No similar characteristics were found between indoor pollution and urban and high-risk sites outdoor pollution, because the poor ventilation of houses and buildings in general allows the concentration of chemical and biological pollutants that are not found in similar outdoor concentrations also in severe pollution event. Urban outdoor air pollution refers to the air pollution which the populations are exposed to, living in and around the urban area. Indoor air pollution refers to the pollutants found in indoors. An important difference is in the heavy metals concentration, generally most abundant and with major variability of species in urban and industrial air outdoor pollution compared with indoor pollution.

At the moment, in Italy, a reference rule has not been set. For this reason, until today, the main information concerning some guidelines or reference values in indoor air is obtained by the international scientific literature or by the few guidelines issued by other European countries or, for analogy, by other guidelines values regarding outdoor air. However, public health awareness on indoor air quality still lags significantly behind that of outdoor air quality.

The main areas at high risk of environmental crisis in Italy are described below.
