Indoor Air Pollution

The presence of polluted air inside livable spaces is as old as civilization itself. In earlier societies, the primary causes of pollution came from burning wood, peat, and fossil fuels in conjunction with poor ventilation. However, present-day sources of indoor air pollution are more varied and have wide-ranging health consequences. Sources of indoor pollution include ambient air pollutants, bioaerosols, and physical pollutants such as radon, asbestos, heavy metals and particulates; volatile organic compounds such as formaldehyde, polynuclear aromatic compounds, polychlorinated biphenyls; pesticides; and noise.

Many people assume the air inside their homes or offices are cleaner than the air outside. This, however, is not necessarily true. While indoor air does not have automobile or factory emissions to contend with, there are many other pollutants that are found indoors. In most cases, there are multiple pollutants [Page 902]that can be found in the home. While pollutant levels from individual sources may not pose a significant health risk by themselves, most homes have more than one source that contributes to indoor air pollution. Alone, these pollutants are not significant but their cumulative effect poses a serious health risk.

Asbestos is a major source of indoor air pollution and can be found mostly in older homes within pipe and furnace insulation materials and floor tiles. Each of these presents a significant health risk indoors. Smoking is one of the largest sources of indoor air pollution and is a significant cause of lung cancer. Tobacco smoke contains many different chemicals that cannot be completely eliminated with ventilation and air filters. Carbon monoxide and nitrogen dioxide are emitted by combustion products like stoves, fireplaces, and heaters. These gases comprise a large health risk and at high concentrations can lead to death. Outside, the health risk presented by these pollutants is much smaller and not of much concern.

Asbestos, a fibrous mineral, is most often too small to be seen by the naked eye and is found mostly in building material; when asbestos fibers become damaged, they can become airborne and are a serious health risk. Asbestos is common on surfaces in older buildings; the exposure of these materials to wear and damage makes the asbestos likely to fray. Because of the small size of asbestos fibers, once they are inhaled, they accumulate in the lungs. The symptoms of diseases caused by continual exposure may not be noticed until years later. Asbestos can cause lung cancer, mesothelioma (a cancer of the chest and abdominal linings), and asbestosis (irreversible lung scarring that can be fatal). In removing asbestos, it is possible that it could become airborne, so as long as it is in good condition, there is no health risk.

Tobacco smoke contains many different compounds, some of which can lead to cancer and other respiratory diseases. Tobacco smoke contains approximately 4,700 different types of chemicals. There is an obvious health risk among people who smoke; however, because of secondhand smoke, there is a significant health risk among people who do not smoke. Indoors, tobacco smoke tends to become concentrated, even with ventilation and air filters, which cannot eliminate it completely, mainly because of the large number of pollutants such smoke contains. Tobacco smoke is the leading cause of lung cancer; the best defense against it is to eliminate it from indoor settings.

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