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AIRBORNE PARTICLES AND HEALTH : HEI EPIDEMIOLOGIC EVIDENCE

HEI-funded epidemiologic research has addressed major issues concerning interpretation of previously reported associations between particulate matter (PM)1 and adverse health effects. This essay reviews the key contributions of HEI’s PM epidemiologic research program. To highlight these contributions, the text refers selectively to what is now a large epidemiologic literature on the health effects of PM, but this essay is not intended as a comprehensive review of either that literature or the evidence it provides on the health effects of PM. Specifically, the essay addresses the possibility that the widely reported associations between exposure to PM and adverse health effects could be interpreted as being due to other factors: environmental factors that vary with time in the same way as PM (eg, the weather, other air pollutants) or errors in measurement of exposure, for examples. The essay also considers the extent of lifeshortening associated with exposure to PM and whether long-term exposure is associated with increased mortality from cardiac and/or pulmonary disease. The results of HEI-funded research strengthen the evidence for adverse effects of PM and help to define some remaining questions important for causal inference and public health decision-making.