What do epidemiologic findings tell us about health effects of environmental aerosols?

In the last 10 years there has been an abundance of new epidemiological stu dies on health effects of particulate air pollution. The overall evidence s uggests that fine particulate pollution can be an important risk factor for cardiopulmonary disease. Long-term, repeated exposure to fine particulate air pollution may increase the risk of chronic respiratory disease and the risk of cardiopulmonary mortality. Short-term exposures exacerbate existing cardiovascular and pulmonary disease and increase the risk of becoming sym ptomatic, requiring medical attention, or even dying, This paper outlines t he results of the basic epidemiologic studies and briefly reviews and discu sses recent studies that have looked at specific physiologic health endpoin ts in addition to lung function. A few recent, mostly exploratory pilot stu dies, have observed particulate pollution associations with blood plasma vi scosity, heart rate, heart rate variability, and indicators of bone marrow stimulation. A systemic response to particulate-related pulmonary inflammat ion remains somewhat speculative. The epidemiologic evidence, nevertheless, seems consistent with the hypothesis that particle-induced pulmonary infla mmation, cytokine release, and altered cardiac autonomic function may be pa rt of the pathophysiological mechanisms or pathways linking particulate pol lution with cardiopulmonary disease.