Observation And Research, In The Beijing Urban Area Of ​​a Single Point Of Aerosols Of Fine Particles (pm2.5)

From 2001 to 2003, some seasonal experimentations of " Beijing City Air Pollution Observation field Experiment" had been carried through intensively. The observation of aerosol on the top of a high building in Baishiqiao was included. In this experiment, PM2.5 and PM10 continuous mass concentration data had been collected , ionic and elementary component, organic carbon and elemental carbon sample had been analyzed. From all these, we concluded that: The seasonal and daily variation of PM2.5 mass concentration are distinctive. It is high in winter and low in summer. But in few summer weather, the pollution of PM2.5 is serious. Every day, it is low in afternoon, high in night comparatively, it reduces along with the traffic increasing. The mass concentration of PM2.5 varies distinctive instantaneously. From the analysis of chemical components we found that the organic carbon in PM2.5 is belongs to secondary OC. Meteorological conditions affect PM2.5 greatly. When the wind speed exceed 3m/s, the PM2.5 varies slowly. It increases when the relative humidity increasing, and it reduces greatly after raining or snowing. The correlation between PM2.5 and PM10 is evident. They have same seasonal and daily variation. But the PM2.5/PM10 is different in each season. It is high in winter and low in summer. The difference of this value between winter and summer is 10-20%. The value of anthropic pollution element and NO-3,SO42-, NH4+ account for a larger proportion in PM2.5 than in PM10. The main sources of PM2.5 are the dust from soil , soot and construction, and the exhaust gases. The long distance transportation from vicinage maybe also gives contribution to regional PM2.5 pollution in Beijing.