ABSTRACT
Several air pollution episodes documented over the last seven decades have been associated with significant increases in mortality in the exposed population. The most commonly cited events occurred in the Meuse Valley, Belgium, in 1930, Donora, Pennsylvania, in 1948, and in London, England, in 1952 (1). Daily death rates (primarily of respiratory and cardiovascular complications) during or immediately after these episodes increased up to ten times the normal level. More recent studies have reported that less extreme increases in airborne particulates, which occur regularly in urban and industrial areas of Europe and North America, are also associated with increased hospital admissions for pneumonia, asthma, and bronchitis (2,3). These acute effects are thought to occur most frequently in persons with preexisting cardiopulmonary disease (see Chaps. 15, 18, and 19), as a result of additional oxidative, neurogenic, and inflammatory stresses on an already weakened condition.
