重庆主城区春季大气PM_(10)及PM_(2.5)中多环芳烃来源解析

Source Apportionment of Polycyclic Aromatic Hydrocarbons in PM_(10) and PM_(2.5) in Spring in Chongqing

于2012年春季采集了重庆主城区和缙云山共6个环境采样点的大气PM10、PM2.5样品,同步采集了燃煤尘、机动车尾气尘、施工机械尾气尘、船舶尾气尘、餐饮油烟尘、生物质燃烧尘及土壤尘等7类污染源,采集到有效受体样品139个、有效源样品233个,使用GC-MS分析样品中18种PAHs的质量浓度（ρ）,分析了PM10、PM2.5上载带PAHs的污染特征,并分别运用比值法、主成分分析法及CMB（化学质量平衡）受体模型法对PM10、PM2.5中的PAHs进行来源解析,所得源解析结果较为一致.结果表明：重庆主城区大气PM10、PM2.5中ρ（PAHs）较低,ρ（PAHs）分别为22.03~31.71、19.02~29.92 ng/m^3,其中位于工业区新山村采样点的ρ（PAHs）最高.PM10载带的PAHs有86%~99%集中在PM2.5中,说明PAHs主要富集在PM2.5中.重庆主城区大气PM10、PM2.5载带的PAHs主要来自机动车尾气尘和燃煤尘的贡献,这2类源对PM10的贡献率分别为25.89%、32.80%;而在PM2.5中,机动车尾气尘的贡献率较高,可达62%左右.

In order to study the source identification of PAHs in Chongqing City, both ambient concentrations and sources of PM10 and PM2.5 were investigated. Ambient samples were collected from six sites for seven kinds of sources （coal emissions, vehicle exhaust, construction machinery dust, ship exhaust, oil fumes, biomass burning and soil） in spring. In total, 139 ambient samples and 233 source samples were included. Eighteen species of PAHs in the samples were analyzed by GC-MS. Source identification and apportionment of PAHs were investigated by diagnostic ratios, principal component factor analysis （PCA） and chemical mass balance （CMB） receptor model. The results showed that total PAHs concentrations in PM10 and PM2.5 of Chongqing City ranged from 22. 03-31.71 ng/m^3 and 19.02-29.92 ng/m^3 , respectively. Spatial variation showed that the highest total PAHs concentration was at Xinshancun site. 86% -99% of the total PAHs in PM10 were concentrated in particles of PM2.5 , indicating that PAHs were mostly enriched in fine particulates. Source apportionment showed that coal combustion and vehicle emissions were the two major sources for PAHs in PM10 and PM25. For the total PAHs in PMl0, vehicle emissions and coal combustion accounted for 25.89% and 32.80% , respectively, while vehicle emissions were the source of a significantly higher percentage, about 62% , of PAHs in PM2.5.