Spatial-temporal variation and accumulation effect of air pollutants over Beijing Area

Spatial and temporal variation of PM10 and SO2 over Beijing area is obtained by analysis of monitoring data in 1999 and 2000. Random walk simulations are carried out to reveal impact of the urban emission to whole simulation domain. Accumulation effect of air pollutants in this area is also discussed. Results show that 1) Spatial distribution of PM10 and SO2 concentration is centered to urban area of Beijing and characterized by distinct diurnal and seasonal variation. 2) Diurnal variation of air pollutant concentration in urban area differs obviously from that in clean station Dingling (background site). The former peaks twice in a day while the latter has a single peak. 3) Conditional statistics of monitoring data with the support of the random walk simulations show evident influence of urban emission to the clean station, Dingling. 4) Air pollutants may accumulate essentially over the simulation domain in winter, with a time scale 2-5 days approximately. The advection-diffusion factor plays a crucial role in the local accumulation process of air pollutants.EI06930-9384