Abstract: A typical stagnant air pollution episode happened during October 1 to 10, 2004 in Beijing. Using the method of footprint analysis and the monitoring data for major pollutant (PM10 in this period, detailed process and the source-area of potential influence in this episode were analyzed. Results illustrate that: 1 the diurnal variation of PM10 concentration differs significantly from usual case, and high concentration appeares in the afternoons and evenings, 2 the horizontal distribution of PM10 concentration has a pattern as “the higher in the south and the lower in the north”, and 3 the development of the episode is accompanied with obviously extending of the footprint 100-200 km to the southwest of Beijing, suggesting that source emission from the southwest may contribute significantly to this heavy pollution episode.

Key words: air pollution episode, footprint analysis, PM10, stagnant weather, Beijing

摘要： 2004年10月1-10日，北京出现了一次典型的大气静稳型重污染过程。利用印痕(footprint)分析方法，结合主要污染物PM10的逐时浓度监测数据，对这次静稳型重污染过程及其影响源地进行分析。结果表明： 1 重污染过程中PM10浓度的日变化特征有明显改变，下午和晚上出现高浓度； 2 北京地区PM10浓度的水平分布总体呈“南高北低”形势； 3 重污染发展阶段伴随着印痕分布区域不断朝偏西南方向延伸的过程，延伸区域达100～200 km，反映西南方向源区对这次重污染的明显贡献。

关键词: 重污染, 印痕分析, PM10, 静稳型, 北京