中文摘要：

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100～200km，反映西南方向源区对这次重污染的明显贡献。

英文摘要：

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 diffem 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.