北京市夏季大气气溶胶PM_(2.5)和PM_(10)成分特征

Atmospheric aerosol compositions of PM_(2.5) and PM_(10) in summer in Beijing,China

对北京市城区2012年夏季大气对气溶胶进行每日PM2.5和PM10石英膜采样,得到了可溶性离子质量浓度和16种元素的质量浓度,并结合气象观测值进行了分析.结果显示,采样期间,PM2.5质量浓度为9.58~210.42μg·m-3,平均值102.81μg·m-3;PM10质量浓度为33.75~288.33μg·m-3,平均值159.66μg·m-3.PM2.5和PM10质量浓度都与采样点能见度、风速呈负相关,与相对湿度呈正相关.质子荧光分析（PIXE）结果显示,S、K、Ca和Fe在PIXE可分析元素中含量较高,在PM2.5和PM10都占89%.且元素Ca、Ti、Sc、Cr、Fe主要存在于粗粒子（PM2.5~10）中,而元素S、Cu、Zn、As、Br、Pb主要存在于细粒子（PM2.5）中.富集因子分析表明,元素K、Ca、Ti、V、Mn、Ni主要为地壳来源,元素S、Cl、Cu、Zn、As、Br、Pb主要来自于人为源.SO2-4、NO-3、NH＋43种可溶性离子总质量浓度占PM2.5浓度的43.5%,占PM10浓度的25.4%.

Daily atmospheric aerosol PM2. 5 and PM10 were sampled on quartz films in urban Beijing in the summer of 2012. Mass concentration, water-soluble ionic composition, concentration and enrichment factors of 16 elements were investigated. The correlation between meteorological conditions and aerosol concentrations were investigated. The weighted mass concentration of PM2.5 was found to be from 9.58 - 210.42 μg · m^-3, with an average value of 102.81 μg · m^-3. The weighted PM10mass concentration was found to be from 33.75- 288.33μg · m^-3,with an average value of 159. 66μg · m^-3. Both PM2.5 and PM10 concentrations showed inverse correlation with visibility and wind speed, but positive correlation with relative humidity. PIXE analysis showed that the total mass of elements S, K, Ca and Fe accounted for 89% in PM2.5 and PM10. Elements Ca, Ti, Sc, Cr and Fe mainly remained in coarse particles, but elements S, Cu, Zn, As, B and Pb were mainly present in fine particles. Enrichment factor analysis indicated that elements K, Ca, Ti, V, Mn and Ni were largely from crustal sources, whilst elements S, C1, Cu, Zn, As, Br and Pb were largely from anthropogenic sources. Ions SO4^2-, NO3^- and NH＋ dominated the dissolved ionic components, occupying 43.5 M and 25.4 respectively of total mass concentrations of PM2.5 and PM10.