[Comparison analysis of variation characteristics of SO2, NOx, O3 and PM2.5 between rural and urban areas, Beijing].

The concentrations of SO2, NOx, O3 and PM2.5 were observed continuously at Shangdianzi atmospheric background monitoring station and Baolian urban environmental monitoring station from 2006-01-01 to 2006-12-31. The difference of seasonal variation and diurnal variation between rural and urban areas was analyzed. And the relationship between wind direction and pollutant concentration at background station was discussed. The results showed that. 1) The difference of NOx and SO2 concentrations between rural and urban was most prominent in winter. The concentrations in urban had 4-6 times more than that in rural. The variation trends of O3 were similar in urban and rural. PM2.5 was more than 100 microg/m3 in April and May in rural, which was 2-3 times more than annually average. 2) The diurnal variation of NOx and SO2 showed two peaks, one around 09:00 and the other around 22:00. That showed one peak around 22:00 in rural. The rural ozone daily peak was 2 h later than the urban. The diurnal variation of PM2.5 was not regular. 3) The pollutant concentrations seemed obviously high when southwest wind prevailed and brought the polluted air from urban. Contrarily, that was very low when northeast wind prevailed and brought the clean air.