2016-2021年江苏省扬州市PM_(2.5)中多环芳烃的来源解析及健康风险评价

Source apportionment and health risk assessment of polycyclic aromatic hydrocarbons(PAHs)in PM2.5 of Yangzhou City from 2016 to 2021

分析2016—2021年扬州市大气细颗粒污染物(fine particular matter,PM_(2.5))中多环芳烃(polycyclic aromatic hydrocarbons,PAHs)组分的季节分布特征,解析其潜在污染来源并采用模型评估PAHs对人群的致癌风险评估.研究收集2016年10月至2021年12月扬州市大气PM_(2.5)样本,采用高效液相色谱法(HPLC)对样本中16种PAHs组分进行检测并对季节分布特征作出描述,采用特征比值法和正定矩阵因子分解法(positive matrix factorization,PMF)对其潜在污染来源进行解析,结合苯并[a]芘(BaP)毒性当量法和终身致癌风险模型(ILCR)评估呼吸途径所导致的PAHs对成年和儿童的健康风险.结果表明2016—2021年扬州市大气PM_(2.5)浓度范围的变化范围为2—483μg·m^(−3),ΣPAHs的浓度范围为0.43—76.63 ng·m^(−3),两者均呈现冬季浓度最高,夏季浓度最低的浓度变化特征.不同环数PAHs的浓度占比中,4环PAHs占比最大(49.14%),2环PAHs在4个季节中占最低(0.79%).采用特征比值法结合PMF模型进行分析,扬州市近年来当地空气环境受燃煤、生物质燃烧和交通源排放影响较为突出.BaP毒性当量法表现为:冬季>春季>秋季>夏季.5年来成人和儿童的总致癌风险平均值分别为3.504×10^(−6)、0.943×10^(−6),成人呼吸途径的健康暴露风险高于儿童,和儿童仅在冬季有一定程度致癌风险相比,成人在春季、秋季和冬季均存在不同程度的暴露风险.研究显示2016—2021年扬州市大气PM_(2.5)中的PAHs含量呈现明显的季节性变化,其主要来源于汽油、汽车尾气以及燃煤燃烧.在目前的PM_(2.5)中多环芳烃的水平下,成人和儿童均存在一定潜在致癌风险,尤其是在冬季外出时需做好防护工作.

This study explored the seasonal distribution characteristics of polycyclic aromatic hydrocarbons(PAHs)in atmospheric fine particulate matters(PM_(2.5))in Yangzhou City from 2016 to 2021,aiming to apportion PM_(2.5)-bounded PAHs to main source categories and estimate the carcinogenic risks of total PAH.PM_(2.5)samples were collected from October 2016 to December 2021,and sixteen PAHs were analyzed using the high-performance liquid chromatography(HPLC).Source apportionment was conducted via the diagnostic ratio method and positive matrix factorization(PMF)method.The inhalation-related carcinogenic risks of PAHs to adults and children were assessed using BaP toxicity equivalent method and the individual lifetime cancer risk(ILCR)model.PM_(2.5)concentrations ranged from 2μg·m^(−3)to 483μg·m^(−3),with theΣPAHs concentration from 0.43 ng·m^(−3)to 76.63 ng·m^(−3).Both PM_(2.5)andΣPAHs concentrations were the highest in winter and the lowest in summer.Among different PAHs ring structures,4-ring PAHs accounted for the largest proportion(49.14%),while 2-ring PAHs were the least prevalent(0.79%).The source apportionment results indicated that the local air pollutants were primarily from coal combustion,biomass burning,and vehicle emissions.The average total carcinogenic risk over the study period was 3.504×10^(−6) for adults,higher than that for children(0.943×10^(−6).The risk only existed in winter for children,while adults were at risk in spring,autumn,and winter.Stringent regulations targeting the PM_(2.5)-bounded PAHs,especially those from vehicle emission and coal combustion,are warranted for the health benefits of both adults and children in Yangzhou City.