吕梁市PM_(2.5)中多环芳烃的来源解析及健康风险评价

Source Analysis and Health Risk Assessment of PAHs in PM2.5,Lüliang City

为探索吕梁地区PM_(2.5)中多环芳烃的季节变化、健康风险和潜在来源,于2018年10月23日至2019年7月1日对离石区(市区)和孝义市(郊区)进行PM_(2.5)样品采集,利用气相色谱-质谱联用仪(GC-MS)测定了14种多环芳烃浓度.总多环芳烃的浓度年均值为95.50 ng·m^(-3),主要以5~6环为主(49.7%),3环占比较低(8.3%);吕梁市多环芳烃浓度呈现冬季>秋季>春季>夏季的季节性变化规律,市区浓度年均值(130.47 ng·m^(-3))高于郊区(84.4 ng·m^(-3));增量终身致癌风险和蒙特卡洛模拟结果均表明吕梁市多环芳烃毒性服从成人>青年>儿童的规律,除夏季外,离石区增量终身致癌风险值均在10^(-6)~10^(-4)之间,远高于孝义市,表明市区存在较高的多环芳烃潜在风险;通过采用特征比值法和正定矩阵因子分解模型表明,吕梁市多环芳烃主要来自于煤和生物质的燃烧(61.9%)和机动车尾气排放(38.1%),由后向轨迹和潜在源因子贡献分析模型确定吕梁市多环芳烃潜在源主要分布在山西南部、陕西北部和内蒙古西部.

To investigate the seasonal variation,health risks,and potential sources of polycyclic aromatic hydrocarbons(PAHs)in PM_(2.5) in the Lüliang area,PM_(2.5) samples were collected in Lishi District(downtown area)and Xiaoyi City(suburban area)from October 23,2018 to July 1,2019,and the concentrations of 14 PAHs were determined using gas chromatography-mass spectrometry(GC-MS).The annual average concentration of PAHs was 95.50 ng·m^(-3),and the concentration of 5-6 ring PAHs was mainly(49.7%),with 3 ring PAHs accounting for a relatively low proportion(8.3%).The concentration of PAHs in Lüliang City showed a seasonal pattern of winter>autumn>spring>summer.The results of the ILCRs model and Monte Carlo simulation showed that the toxicity of PAHs in Lüliang City followed the rule of adults>youth>children.Except in summer,the ILCRs values in the Lishi area were between 10^(-6) and 10^(-4),much higher than those in Xiaoyi City,indicating that there was a high potential risk of polycyclic aromatic hydrocarbons in the urban area.Through the characteristic ratio method and positive matrix factorization(PMF),it was shown that the PAHs in Lüliang City were mainly from the combustion of coal and biomass(61.9%)and vehicle exhaust emissions(38.1%).Based on the backward trajectory and potential source factor contribution analysis model,it was determined that the potential sources of PAHs in Lüliang City were mainly distributed in southern Shanxi,northern Shaanxi,and western Inner Mongolia.