Indoor Air Pollution in Industrialized Countries

Indoor environment comprises ordinary living confined spaces as well as non-industrial work-places. Indeed, for industrial working environment there is a specific regulation assessed by hygienists and occupational physicians. Indoor exposure mainly occurs in public and private buildings, offices, community structures (hospitals, schools, barracks, hotels, banks, etc.), premises for recreational and/or social activities (cinemas, bars, restaurants, shops, sports facilities, etc.), or in microenvironments, such as public or private transport (cars, buses, trains, subways, airplanes.). Indoor environment contributes significantly to human exposure to air pollutants in industrialized countries, which can be defined as countries that have a developed economy and advanced technological infrastructure relative to other less industrialized nations. Most commonly, the criteria for evaluating the degree of economic development are gross domestic product, gross national product, the per capita income, level of industrialization, amount of widespread infrastructure and general standard of living (Investopedia website). The 31 industrialized countries, listed in the world population review website, have a per capita gross domestic product that exceeds $15.000, although there are a few exceptions (Worldpopulationreview website). In industrialized countries, people spend up to 90% of their time indoors, especially at home, at school, or at work. There is consistent evidence that exposure to indoor pollutants increases the risk of several respiratory/allergic symptoms and diseases (Viegi et al., 2004; Baldacci et al., 2015). Furthermore, a relevant quota of indoor pollution derives from tobacco smoking, which is the major source of indoor particulate matter (PM). Conversely, in developing countries, elevated concentrations of indoor PM are mainly associated with biomass combustion for heating and cooking. However, biomass combustion is increasing, especially in winter, also in the developed world.