Measurement of acidic gas by Annular Denuder System (ADS) in Sha‐Lu, Taiwan

During June 1999 to January 2000, the concentrations of acidic gas were measured by ADS (annular denuder system) in central Taiwan, Taichung. The concentration of HNO2, HNO3, SO2, NH3and HCl were 2.81, 1.63, 24.69, 15.75 and 1.08 μg/m3, respectively. For the seasonal variations of acidic gases, the average SO2and NH3concentrations were higher in summer, and lower in winter. Contrarily, the HNO2and HNO3concentration were lower in summer, and higher in winter. Four meteorological factors: wind speed (m/s), wind direction, temperature (°C) and relative humidity (%) were taken into account in this study. Concentrations (μg/m3) of SO2and NH3were moderate positive related to temperature (°C) with R2 value of 0.668 and 0.678, respectively. The highest value of average SO2gas concentrations appeared in the SSW direction. It meant that the Taichung thermal power station which located in the west side of the sampling site were not the largest SO2contributor to the sampling area. The factories surrounded in...