To collect and evaluate an aerosol acidity (H^+) in ambient air, the cyclone/annular denuder/filter pack sampling system (ADS) was used. Aerosol acidity was collected in Chicago using the ADS for 81 12-hr samples divided in spring/summer/fall 1990 and winter 1991. This study illustrated that the ADS was suitable for measuring aerosol acidity. The 10^-5N HClO_4 extraction solution for pH determination provided more reliable scale than 10^-4N HClO_4. NH_3 should be removed prior to particle collection to accurately measure H^+ concentration on the filter. There was seasonal variation in aerosol acidity concentrations. Aerosols were more acidic in the summer. High correlations between SO_4^2- and NH_4^+, and between SO_4^2+ and H^+ were observed during the entire sampling period.

• Hak Sung Lee | 이학성