成都市PM10中多环芳烃来源识别及毒性评估

摘要

对成都市2009年冬夏两季可吸入颗粒物(PM10)中16种多环芳烃(PAHs)含量进行了研究,并进一步分析其空间分布、组成特征及来源.结果表明,16种PAHs中15种被普遍检出(Nap未检出),冬季和夏季的ΣPAHs浓度范围分别为40.25~150.68ng/m3和44.51~71.16ng/m3,平均浓度分别为88.36ng/m3和64.21ng/m3.空间分析表明,PAHs 浓度在工业区较高,背景点较低.从 PAHs 组分分析结果显示,低环含量较低,4~6环所占比例较大,其比例范围为86.7%~96.1%.各组分含量季节差异不明显.利用特征化合物比值法、等级聚类法、PCA解析法分析了污染源类型,结果表明成都市PM10中PAHs的主要来源是机动车尾气排放源,以及煤与木材燃烧源.通过BaP当量(BaPE)进行了毒性评估,结果显示成都市冬夏两季的BaPE均值分别为13.41ng/m3和9.54ng/m3.%PM10-associated polycyclic aromatic hydrocarbons (PAHs) were investigated in summer and winter 2009 from Chengdu, China. A total of 16 priority PAHs were measured, with the total concentrations (ΣPAHs) (ng/m3) ranging from 40.25 to 150.68 in winter and from 44.51 to 71.16 in summer, respectively. The average concentration of ΣPAHs were 88.36 in winter and 64.21 in summer. Meanwhile, the spatial distribution of PAHs was discussed. The results showed that theΣPAHs in industry region exhibited the highest concentration while those in the background region showed the lowest level. In order to explore composition of PAHs, characteristics of low ring and high ring PAHs were explored. The high ring PAHs presented high fractions (86.7%~96.1%), indicating that the PAHs might be formed in high temperature combustion processes. In addition, in order to investigate potential source categories of PAHs in PM10, three statistical methods (ratio method, hierarchical cluster analysis, principal component analysis) were employed. Agreement results were obtained from above-mentioned different methods, suggesting that the main source categories of PAHs were vehicle emission and coal and wood combustion. Finally, the risk assessment of PAHs was determined by Benzo(a)pyrene equivalent (BaPE), which suggested that the toxicity of PAHs was at high level during winter and summer time.