北京城市居民冬季个体暴露PM_(2.5)中多环芳烃特征与室外的差异研究

Differences on characteristics between personal and outdoor exposure to polycyclic aromatic hydrocarbons in PM_(2.5) for urban residents in winter in Beijing

目的比较个体暴露PM_(2.5)中多环芳烃的污染特征与室外的差异。方法于2016年12月用个体采样器采集北京城市8名志愿者的24 h个体暴露PM_(2.5)样品及同期室外大气PM_(2.5)样品,采用气相色谱-质谱法测定PM_(2.5)中多环芳烃浓度,比较个体暴露PM_(2.5)中多环芳烃的浓度、构成特征、特征因子比值、毒性与室外的异同。结果PM_(2.5)中12种多环芳烃个体暴露浓度与室外浓度的比值(P/O值)平均值范围为0.24~0.83,12种多环芳烃总量(∑PAH_(12))的P/O值平均值为0.54。个体暴露PM_(2.5)中不同环数多环芳烃的占比从高到低依次为5~6环>4环>3环,与室外4环多环芳烃占比最高的构成特征不同。个体暴露PM_(2.5)中多环芳烃的特征因子比值与室外差异无统计学意义(P>0.05)。12种多环芳烃的苯并[a]芘等效毒性总量(∑BEQ)的P/O值平均值为0.67。二苯并[a,h]蒽和苯并[a]芘对PM_(2.5)中多环芳烃的∑BEQ贡献最高。结论个体暴露PM_(2.5)中多环芳烃的浓度及构成特征与室外不同,如在人群健康风险评估中以室外大气PM_(2.5)中多环芳烃浓度作为研究对象的暴露水平,将高估其健康风险。

Objective To investigate the difference about characteristics of polycyclic aromatic hydrocarbons in PM_(2.5)between personal exposure and outdoor.Methods PM_(2.5)samples of 24-hour personal exposure from eight volunteers and the outdoor PM_(2.5)samples were collected using personal exposure samplers in December 2016 in Beijing.Concentrations of multiple polycyclic aromatic hydrocarbons were measured by GC-MS/MS.The concentration,constitutive characteristics,characteristic factor ratio and toxicity of the polycyclic aromatic hydrocarbons in PM_(2.5)samples were analyzed.Results Personal exposure/outdoor concentration ratio value(P/O value)of 12 polycyclic aromatic hydrocarbons in PM_(2.5)were ranged from 0.24 to 0.83,and the average P/O value of the total 12 polycyclic aromatic hydrocarbons(∑PAH_(12))was 0.54.In personal exposure PM_(2.5),the proportion of polycyclic aromatic hydrocarbons with different ring numbers ranked as the order:5-6 rings>4 rings>3 rings.While in outdoor PM_(2.5),4-ring polycyclic aromatic hydrocarbons account for the largest proportion.There was no statistically significant difference between the characteristic factor ratio of polycyclic aromatic hydrocarbons in PM_(2.5)from personal exposure and the outdoor.The average P/O value of the total benzo[a]pyrene equivalent toxicity(∑BEQ)of 12 polycyclic aromatic hydrocarbons was 0.67.Dibenz[a,h]anthracene and benzo[a]pyrene contributed the most to the∑BEQ of polycyclic aromatic hydrocarbons in PM_(2.5).Conclusion The concentration and constitutive characteristics of the polycyclic aromatic hydrocarbons in personal exposure PM_(2.5)are different from those in outdoor.Hence,in the study of inhalation exposure risk of polycyclic aromatic hydrocarbons in PM_(2.5),application of outdoor concentration as personal exposure level will lead to the overestimation of real personal exposure level.