The expanding role of air pollution in cardiovascular disease: does air pollution contribute to risk of deep vein thrombosis?

Scientific efforts to understand the health effects of air pollution and public policy efforts to control air pollution have a fascinating history. The early “killer smog” episodes in Meuse Valley, Belgium (1930), Donora, Pa (1948), and London, UK (1952) provided stark evidence of deleterious respiratory and cardiovascular health effects of severe air pollution exposure. This evidence motivated early public policy efforts to improve air quality. In the United States, Britain, and elsewhere, legislative, regulatory, and related efforts to control air pollution were initiated. Ambient air quality standards and guidelines were established. Severe air pollution episodes were largely mitigated, and concern about adverse air pollution–related health effects abated. Nearly all air pollution researchers agreed that air pollution at very high concentrations posed serious health hazards. By the late 1970s and through the 1980s, however, it was argued by many that air pollution, at levels then common to the United States and Britain, was no longer a significant threat and that the potential health effects of air pollution could not be disentangled from effects from other factors.1