2017年秋季长春市PM2.5中多环芳烃的污染来源及健康风险评价

Source Apportionment and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in PM2.5 in Changchun City,Autumn of 2017

本研究采集了长春市2017年秋季大气中的PM2.5样品共30个,采用气相色谱质谱仪(GC-MS)分析了样品中17种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的浓度和组成特征,运用比值法和主成分分析法确定PAHs的污染来源,并通过计算苯并(a)芘等效致癌浓度和终身致癌超额危险度进行健康风险评估.结果表明,长春市秋季PM2.5平均质量浓度为(50.84±12.23)μg·m^-3,有机碳(OC)和元素碳(EC)含量分别为(17.07±5.64)μg·m^-3和(1.33±0.75)μg·m^-3,占PM2.5总量的37%;PAHs总浓度为(15.69±5.93)ng·m^-3,以中高环数的PAHs为主,占总PAHs的84.26%;长春市秋季大气中PAHs主要来源于机动车尾气排放(44.48%)>煤燃烧(29.16%)>生物质燃烧(26.36%),本地交通(汽油车)排放是主要污染源;苯并(a)芘等效致癌平均浓度在1.55~5.38 ng·m^-3之间,总致癌等效平均浓度为(6.44±1.53)ng·m^-3,总体处于轻微污染水平;通过呼吸摄入PAHs对成年女性健康危害最大,其次是成年男性和儿童,但所有人群的终身致癌风险值均未超过1×10-6,其健康风险处于可接受水平.

In this study,30 PM2.5 samples were collected from the atmosphere in Changchun City in the autumn of 2017.The concentration and composition characteristics of 17 polycyclic aromatic hydrocarbons(PAHs)in the samples were analyzed by gas chromatography mass spectrometry(GC-MS).The diagnostic ratio and principal component analysis method were used to determine the source of PAHs pollution.The health risk assessment was carried out by both calculating the equivalent carcinogenic concentration of benzo(a)pyrene and the lifetime risk of cancer.Results show that the average PM2.5 concentration in autumn in Changchun is(50.84±12.23)μg·m^-3,and the content of organic carbon(OC)and elemental carbon(EC)are(17.07±5.64)μg·m^-3 and(1.33±0.75)μg·m^-3,respectively,accounting for 37%of the total PM2.5.The total concentration of PAHs is(15.69±5.93)ng·m^-3,which was dominated by medium^-to high-ring-number PAHs,accounting for 84.26%of total PAHs.The atmospheric PAHs in Changchun mainly originate from motor vehicle exhaust emissions(44.48%)>coal combustion(29.16%)>biomass burning(26.36%),local transportation(gasoline vehicles)emissions being the main source of pollution.The average carcinogenic concentration of benzo(a)pyrene is in the range of 1.55 ng·m^-3 and 5.38 ng·m^-3,and the average carcinogenic equivalent concentration is(6.44±1.53)ng·m^-3,which is generally considered a slight pollution level.The ingestion of PAHs by breathing is the most harmful to the health of adult women,followed by adult males and children,however since the lifetime carcinogenic risk value of the entire population did not exceed 1×10-6,their health risks are considered to be at acceptable levels.