The detrimental effects of air pollution on health have been recognized for most of the last century. Effective legislation has led to a change in the nature of the air pollutants in outdoor air in developed countries, while combustion of raw fuels in the indoor environment remains a major health hazard in developing countries. The mechanisms of how these pollutants exert their effects are likely to be different, but there is emerging evidence that the toxic effects of new photochemical pollutants such as nitrogen dioxide are likely to be related to infection.
