PM supersites have been established in the United Sates to study the characteristics of the ambient aerosol, the source and receptor relationship, the impact on health, the formation mechanisms of secondary aerosol, and the comparison among various measurement methods. The air quality in southern Taiwan has been the worst among the seven air basins in Taiwan. Therefore, the purposed of this study are:1.To investigate the chemical compositions of the ambient particles in the southern Taiwan;2.To evaluate the feasibility of using the filters of beta-gauge monitors, which are used in the ambient air quality monitoring station, for chemical analyses;3.To conduct field campaign for PM, H2O2, HCHO, and HNO3 during strong photochemical reaction periods;4.To assess and to plan the establishment of PM supersite in southern Taiwan. The chemical compositions of particles were measured by routine samplings of PM2.5 and PM10 at four different sites simultaneously. The samplings were conducted every six days and the duration of each sampling was 24 hours. The four sites were Tainan, Nanzu, Chunking, and Dailow, and were collocated with the EPA ambient air quality monitoring stations. The greatest PM concentrations were observed at Dailow, which was also obtained from the routine beta-gauge monitoring. The dominant chemical species for both PM2.5 and PM10 were sulfate, nitrate, and ammonia. Similar results were also found during the intensive field campaign in October. Note that the three-hour average PM2.5 concentrations at Dailow may be greater than 100 ug/m3. The concentrations of H2O2 were from 0.11 to 3.9 ppbv and 0.26 to 2.5 ppbv at Tainan and Dailow, respectively. The peak H2O2 concentrations were always around noon to 2 o’clock in the afternoon. The peak concentrations of HNO3 were also around noon due to its formation from photochemical reaction but the diurnal cycle of HNO2 was contrary to that of HNO3.

supersites、secondary aerosol、particle characterization