MEASUREMENT OF ACIDIC AEROSOL SPECIES IN EASTERN-EUROPE - IMPLICATIONS FOR AIR-POLLUTION EPIDEMIOLOGY

A large number of studies have indicated associations between particul ate air pollution and adverse health outcomes. Wintertime air pollutio n in particular has been associated with increased mortality. Identifi cation of causal constituents of inhalable particulate matter has been elusive, although one candidate has been the acidity of che aerosol. Here we report measurements of acidic aerosol species made for approxi mately 1.5 years in Erfurt, Germany, and Sokolov, Czech Republic. In b oth locations, the burning of high-sulfur coal is the primary source o f ambient air pollution. Twenty-four-hour average measurements were ma de for PM(10),[particulate matter with an aerodynamic diameter (d(a)) less than or equal to 10 mu m(3)], as well as fine particle (d(a) < 2. 5 mu m) H+ and SO42- for the entire study. Additionally, separate day and night measurements of fine particle H+, SO42- NO3-, and NH4+ and t he gases, SO2, HNO3, HONO and NH3 were collected with an annular denud er/filter pack system over a 7-month (late winter-summer) period with additional measurements during pollution episodes the following winter . At both sires, 24-hr SO2 (mean concentrations of 52 mu g/m(3), with peak levels of > 585 mu g/m(3)) and PM(10) (mean concentration 60 mu g /m(3)) concentrations were quire high. However, aerosol SO42- concentr ations (mean concentration of approximately 10 mu g/m(3)) were not as great as expected given the high SO2 concentrations, and acidity was v ery low (mean concentration of < 1 mu g/m(3), with peak levels of only 7 mu g/m(3)). Low acidity is likely to be the result of NH3 neutraliz ation and slow conversion of SO2 to SO42-. These data, along with evid ence that aerosol acidity exposures are significantly lower than ambie nt levels and the reported association between fine particulate air po llution and health outcomes in regions where little aerosol acidity ha s been measured, suggest that particulate acidity alone is not the pri mary component defining fine particulate air pollution toxicity.