四川绵阳大气多环芳烃垂直分布特征及健康风险评价

Vertical distribution characteristics and health risk assessment of atmospheric polycyclic aromatic hydrocarbons in Mianyang,Sichuan Province

为探究四川绵阳山区与城市大气多环芳烃(PAHs)的垂直分布特征,2021年9月16日至12月31日用大气被动采样器在观雾山6个海拔高度与绵阳电视塔5个海拔高度上开展了PAHs样品采集,并对其含量与组成进行了分析。结果表明:(1)绵阳山区与城市大气中16种PAHs的平均质量浓度分别为3.38、26.59 ng/m 3。大气PAHs浓度在山区基本随海拔(682~1680 m)升高而降低,在城市则随海拔升高先降再升又再降。(2)3环PAHs质量浓度占比最高(51.1%~73.4%),占主导地位。(3)大气中PAHs的来源主要为燃煤和交通排放。(4)绵阳大气PAHs中主要毒性物质为苯并[a]蒽。城市、山区吸入导致的超额致癌风险值分别为1.55×10^(-5)、2.36×10^(-6),且城市为山区的6.57倍。

In order to explore the vertical distribution characteristics of atmospheric polycyclic aromatic hydrocarbons(PAHs)in mountain and urban areas of Mianyang,Sichuan,the PAHs at 6 altitudes of Guanwu Mountain and 5 altitudes of Mianyang TV Tower were collected by the passive atmospheric samplers from September 16 to December 31,2021,and then the content and composition were analyzed.The results showed that:(1)the average mass concentrations of 16 PAHs in the atmosphere of Mianyang mountain and urban areas were 3.38 and 26.59 ng/m 3,respectively.The concentration of atmospheric PAHs decreased with the increase of altitude(682-1680 m)in mountain area,while in urban areas,it first decreased,then increased,and then decreased with the increase of altitude.(2)The mass concentration of tricyclic PAHs accounted for the highest proportion(51.1%-73.4%),which were dominant.(3)The PAHs in the atmosphere were mainly from coal combustion and transportation emissions.(4)The main toxic substance in the atmospheric PAHs of Mianyang was benzo[a]anthracene.The excess cancer risk values caused by inhalation in urban and mountain areas were 1.55×10^(-5),2.36×10^(-6),respectively,and urban area was 6.57 times larger than mountain area.