北京秋季气溶胶化学成分的高分辨率观测及来源分析

High-Resolution Observation of Chemical Components of Atmospheric Aerosol in Autumn of Beijing and Its Source Identification

2001年9月30日～10月6日在北京北三环和北四环之间的中国科学院大气物理研究所气象塔院内使用步进采样仪对气溶胶进行了高分辨率连续采样(每2h采集1个样品),并对样品用PIXE方法进行了元素分析,得到20种元素的浓度。分析结果表明,气溶胶各元素浓度随时间的变化趋势基本一致,且日变化特征显著,早晚出现峰值。降雨期间Ti、Si、Fe等元素浓度急剧下降。S、Pb、Cl、Zn等与人类活动相关的气溶胶元素的富集因子很高。因子分析结果表明,北京秋季大气气溶胶主要源于土壤尘、燃煤尘、工业源和汽车尾气排放等。

Aerosol samples were collected continuously by a step sampler with a 2-hour time step during 30 September-6 October 2001 at meteorological tower at the height of 8 m in Beijing.Chemical composition of aerosol samples was analyzed by using PIXE method.The results showed that the diurnal variations of element concentrations were remarkable,and higher pollutant concentrations often occurred in the morning and midnight.Enrichment factors of S,Pb,Cl,Zn in atmospheric aerosol in Beijing which had a close relationship with the human activities were very high.Factor analysis for element concentrations further indicated that main sources affecting atmospheric aerosol concentrations in Beijing were soil matters,coal combustion,industry dust and vehicle emission.