大气降尘中多环芳烃的分布特征及源解析

为探讨大气降尘中多环芳烃的污染水平和来源的解析,于2008年冬、春、夏、秋四个季节采集了北京昌平地区大气降尘样品,采用超声抽提方法,使用GC/MS测定了样品中PAHs的含量。结果表明,冬、春、夏、秋四个季节样品中多环芳烃总量分别为18.6μg/g、17.3μg/g、15.1μg/g和11.0μg/g,单体化合物均值分别为1.04μg/g、0.96μg/g、0.84μg/g和0.61μg/g。与其他城市监测结果比较可知:昌平地区大气降尘中PAHs含量相对较低。使用多种方法对降尘中的PAHs来源进行解析,结果表明:化石燃料燃烧在不同季节中的贡献相对稳定,燃煤在冬季为多环芳烃主要来源之一,在其他季节贡献相对较低。

The Distribution Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in the Dustfall

To explore the pollution levels and major source of polycyclic aromatic hydrocarbons(PAHs) in the dustfall,we collected dustfall samples of Beijing Changping district in winter,spring,summer and autumn of 2008.The samples were extracted by ultrasonic agitation and then analyzed with gas chromatography/mass spectrometry(GC/MS).The results showed that the total concentration of PAHs were 18.6 μg/g,17.3 μg/g,15.1 μg/g and 11.0 μg/g in winter,spring,summer and autumn,respectively,and the average concentration of the individual PAHs were 1.04 μg/g,0.96 μg/g,0.84 μg/g and 0.61 μg/g respectively.Compared with the monitoring results of other cities,the concentrations of PAHs in the dustfall of Changping district were relatively low.The results of PAH source apportionment suggest that the fossil fuel combustion was relatively stable in all seasons,while coal combustion was a major source in winter.