Air Pollution–Related Illness

The major components of air pollution in developed countries are nitrogen dioxide (from combustion of fossil fuels), ozone (from the effect of sunlight on nitrogen dioxide and hydrocarbons), and suspended solid or liquid particles. Burning of biomass fuel is an additional important source of particulate matter indoors in developing countries. Passive smoking can be considered as related.

The effect of air pollution on lung disease can be substantial at high pollution levels, which can trigger asthma and COPD exacerbations. People living in areas with high traffic, especially when stagnant air is created by thermal inversions, are at particular risk. Of the so-called criteria air pollutants (oxides of nitrogen, oxides of sulfur, ozone, carbon monoxide, lead, and particulates), only CO and lead do not affect airways hyperreactivity. Long-term exposure may increase respiratory infections and symptoms in the general population, especially children.

Ozone, which is the major component of smog, is a strong respiratory irritant and oxidant. Levels tend to be highest in the summer, late morning, and early afternoon. Short-term exposures can produce dyspnea, chest pain, and airways reactivity. Children who participate in outdoor sports during high ozone pollution days are more likely to develop asthma. Long-term exposure to ozone produces a small, permanent decrease in lung function.