A time-series analysis of acidic particulate matter and daily mortality and morbidity in the Buffalo, New York, region

A component of particulate matter (PM) air pollution that may provide one b iologically plausible pathway for the observed PM air pollution-health effe ct associations is aerosol acidity (H+). An increasing number of observatio nal studies have demonstrated associations between H+ and increased adverse health effects in the United States and abroad. Although studies have show n significant H+ associations with increased morbidity in the United States , similar associations have yet to be shown with daily mortality. We consid ered a 2.5-year record of daily H+ and sulfate measurements (May 1988-Octob er 1990) collected in the Buffalo, New York, region in a time-series analys is of respiratory circulatory, and total daily mortality and hospital admis sions. Other copollutants considered included particulate matter less than or equal to 10 mu m in aerodynamic diameter, coefficient of haze, ozone, ca rbon monoxide, sulfur dioxide, and nitrogen dioxide. Various modeling techn iques were applied to control for confounding of effect estimates due to se asonality, weather, and day-of-week effects. We found multiple significant pollutant-health effect associations-most strongly between SO42- and respir atory hospital admissions (as indicated by its t-statistic). Additionally, Hi and SO42-. demonstrated the most coherent associations with both respira tory hospital admissions [H+: relative risk (RR) = 1.31; 95% confidence int erval (CI), 1.14-1.51; and SO42-: RR = 1.18, CI, 1.09-1.28] and respiratory mortality (H+: RR = 1.55, CI, 1.09-2.20; and SO42-: RR = 1.24, CI, 1.01-1. 52). Thus, acidic sulfate aerosols represent a component of PM air pollutio n that may contribute to the previously noted adverse effects of PM mass on human health, and the associations demonstrated in this study support the need for further investigations into the potential health effects of acidic aerosols.