【摘要】 用Andersen六段分级大流量采样器(粒径为:10～7.2μm,7.2～3.0μm,3.0～1.5μm,1.5～0.95μm,0.95～0.49μm,≤0.49μm)采集了广州市荔湾区4个季度的大气颗粒物样品,用气相色谱(GC)定量分析了其中的正构烷烃(n-alkanes)组分,用气相色谱-质谱(GC-MS)定量分析了其中的多环芳烃(PAHs)组分。CPI2(代表石油成因的碳优势指数)、CPI3(代表生物成因的碳优势指数)和Wax(植物蜡含量)表明了石油成因的烷烃倾向于富集在细颗粒物上,而生物成因的烷烃倾向于富集在粗颗粒物上。正构烷烃和低相对分子质量多环芳烃表现出双峰模型分布,高相对分子质量多环芳烃呈现单峰模型分布,仅在细颗粒段有一峰值。烷烃和芳烃秋冬季的MMDs(质量中值直径)比春夏季的大。在高温季节化合物优先富集在细颗粒物上,而在低温季节则向粗的颗粒物方向偏移。更多还原

【Abstract】 Seasonal aerosol samples were collected by Andersen Hi-Vol pumpin g system equipped with a five-stage cascade impactor and a backup filter (size ra nge: 10～7.2 μm, 7.2～3.0 μm, 3.0～1.5 μm, 1.5～0.95 μm, 0.95～0.49 μm, and < 0.49 μm) in the Liwan district, Guangzhou. n-Alkanes were measured using ga s chromatography and PAHs using gas chromatography-mass spectrometry analysis. CPI2 (values for hydrocarbons of petroleum origin), CPI3 (values for biogenic n -alkanes) and Wax (values for vegetable wax content) reveal that the n-alkanes of petroleum origin preferentially accumulate in the smaller aerosol, and bioge nic n-alkanes larger aerosol. The log-normal distributions of n-alkanes and s emi-volatile PAHs (low relative molecular mass) are of bimodal model, while non -volatile PAHs (high relative molecular mass) of unimodal, model and the peak v alue is only in the smaller particle. In addition, the different MMDs (mass medi an diameters) for n-alkanes and PAHs are observed in warm periods and cold peri ods. The MMDs for n-alkanes and PAHs in autumn/winter are higher than those in spring/summer. The seasonal effect is related to the hydrocarbon content in the individual particulate fractions, showing a preferential association of n-alkan es and PAHs with large particles in the cold season.更多还原