【摘要】 为了对北京市PM_2.5成分组成及其来源进行全面和深入分析,于2013年8月-2014年7月,在中国科学院城市生态监测站的4个站点（教学植物园、生态中心、蟒山站和大兴采育）开展了样品采集。利用X射线荧光光谱法（XRF）测定PM_2.5的元素组成,利用离子色谱法测定水溶性离子,利用PMF方法进行源解析。结果表明:观测期间4个站点水溶性离子的总平均质量浓度为44.51μg/m³,占PM_2.5质量浓度的61%（质量分数）;水溶性离子的月变化幅度较大,2014年2月出现最高质量浓度,为120.60μg/m³,占全部水溶性例子浓度的比例为94%。观测期间全市平均NO₃^-/SO₄^2-（质量比）较高（0.92）,说明流动源的贡献要大于固定源;源解析结果表明,机动车尾气排放、燃煤排放为北京市PM_2.5的主要污染源。更多还原

【Abstract】 PM_2.5 samples were collected at 4 sites of ecological monitoring center in Beijing from August 2013 to July 2014 in order to investigate the component and source of PM_2.5 in Beijing. X-ray fluorescence spectrometric（XRF） method was used for the determination of elemental composition. PMF（positive matrix factorization） was used for source appointment. Water-soluble ions were measured by ion chromatography. Results showed that total water-soluble ions average mass concentration was 44.51μg/m³, contributing of 61%（mass ratio） PM_2.5 during observation. Monthly average mass concentration of SO₄^2-、NO_<sup>3-、NH₄⁺and Cl^- mostly fluctuated, the maximum value was in February（120.60μg/m³）; the annual average ratio of NO₃^-/SO₄^2- was 0.92. Automotive exhaust and coal emissions was the main pollutants in Beijing by PMF.更多还原