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目的 了解广州市大气PM2.5中多环芳烃(PAHs)的季节污染特征和来源,评价人群健康风险.方法 于2015年1-11月采集了广州市市区3个行政区的采样点的大气PM2.5样品,分析16种PAHs的含量,利用特征比值法识别其主要来源,应用苯并[a]芘(BaP)毒性当量因子和美国EPA推荐的模型评价人群健康风险.结果 3个采样点PM2.5中PAHs总质量浓度范围为1.35～43.13 ng/m3,平均为8.33 ng/m3,其中BaP的平均浓度为0.91 ng/m3;16种PAHs总浓度呈明显的季节变化规律,冬季＞秋季＞夏季＞春季;4个季节PAHs的组成均以5～6环PAHs为主.特征比值法判断出PAHs的主要来源为机动车尾气和煤燃烧.总致癌等效浓度(TEQ)和总致突变等效浓度(MEQ)的平均值分别为2.29 ng/m3和2.13 ng/m3,季节变化特征与PAHs相一致;PAHs通过呼吸暴露对成人和儿童造成的终身致癌超额危险度分别为0.78×10-6和0.55×10-6.结论 广州市大气PM2.5中PAHs的污染水平较低,主要来源为机动车尾气和煤燃烧,PM2.5中PAHs的人群健康风险处在可接受范围内.“,”Objective To study the seasonal variation and source of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 in Guangzhou,and assess the health risk assessment in population.Methods Ambient PM2.5 samples were collected at three sampling sites in Guangzhou and concentrations of sixteen PAHs were detected,seasonal variation and source of PAHs were analyzed by using ratio method,the health risks were evaluated by benzo(a) pyrene (BaP) toxic equivalent factor and the model recommended by EPA.Results The total concentration of the sixteen PAHs were 1.35-43.13 ng/m3 with an average of 8.33 ng/m3 during the sampling period and the average concentration of BaP was 0.91 ng/m3;The highest value of total PAHs appeared in winter,followed by the order of autumn＞ summer＞spring;The distributions of PAHs were largely composed of 5-6 rings PAHs in all seasons;The main sources of PAHs were motor vehicle exhaust and coal burning.The average concentration of toxic equivalent quantity (TEQ) and mutagenic equivalent quantity (MEQ) were 2.29 ng/m3 and 2.13 ng/m3,respectively,andthe seasonal variation were similar to PAHs;The average lifetime cancer risks of PAHs through respiratory exposure for adults and children were 0.78×10-6 and 0.55×10-6 respectively.Conclusion The pollution of PAHs in PM2.5 is lower in Guangzhou,motor vehicle exhaust and coal burning are the major sources,the average lifetime cancer risks of PAHs in PM2.5 to the population are under average risk acceptance.