The Effect of Meteorological Features on Pollution Characteristics of PM2.5 in the South Area of Beijing, China

Based on the air quality monitoring data and meteorological data, the pollution characteristics of PM2.5 in southern Beijing and relationships between PM2.5 levels and meteorological features were analyzed. The results showed that during the investigation period, daily air quality was characterized as "excellent" and "favorable" (<75 <mu>g m(-3)) on 77% of days in southern Beijing, and there were only two days with serious air pollution (>250 mu g m(-3)). The PM2.5 concentration displayed obvious monthly variations with the highest concentration in November and the lowest concentration in August. When PM2.5 pollution episodes occurred (>75 mu g m(-3)) in this area, the wind direction was often south and southeast with low wind speed (<3 m center dot s(-1)), followed by southwest wind; in addition, the air temperature was low (<10 degrees C) and the relative humidity was high (>75%). The air quality of the study area was affected by the pollution transmission form the surrounding areas, especially the southeastern and the southern transmission paths. The PM2.5 concentration was positively correlated with SO2, NO2 and CO, and negatively correlated with O-3. Therefore, to further improve the air quality in the study area, it is necessary to coordinate the control of PM2.5 and O-3.