2018—2022年苏州市城区和县区大气PM_(2.5)的污染特征和源解析及健康风险评估

Pollution characteristics,source apportionment,and risk assessment of PM_(2.5)in urban district and county of Suzhou city from 2018 to 2022

目的了解苏州市城区和县区大气PM_(2.5)中重金属和类金属离子、多环芳烃和水溶性离子的污染特征和来源解析,并评估PM_(2.5)对人群的健康风险。方法2018年1月至2022年12月每月10—16日采集苏州市城区和县区大气PM_(2.5)样品,分别用称重法、离子色谱法和液相色谱法检测大气PM_(2.5)及其主要成分的浓度,并利用PMF模型判断PM_(2.5)的可能来源,采用EPA健康风险模型评估PM_(2.5)对人群的健康风险。结果2018—2022年苏州市城区和县区大气PM_(2.5)的年均浓度分别为40.00μg/m^(3)和43.00μg/m^(3),超标率分别为17.72%和17.89%,差异无统计学意义(P>0.05),但县区大气PM_(2.5)中重金属和类金属离子及多环芳烃浓度高于城区,差异有统计学意义(P<0.05)。苏州市城区大气PM_(2.5)的主要来源为化石燃料燃烧源和交通排放源,县区的主要来源为化石燃料燃烧源和工业源。城区和县区大气PM_(2.5)中重金属和类金属离子对人群产生的HQ值均小于1,非致癌风险较低;两区Cd、Pb和Ni对人群产生的致癌风险CR值均小于1×10^(-6),属于人群可以接受的风险水平,而As和多环芳烃的CR值均大于1×10^(-6),对人群有潜在的致癌风险。结论本次调查的苏州市城区和县区存在大气PM_(2.5)污染且主要污染来源不同,两区PM_(2.5)中的As和多环芳烃对人群有潜在的致癌风险,应针对性地加强对As和多环芳烃主要污染来源的管控。

Objective To understand the pollution characteristics and source of metal and metalloid,polycyclic aromatic hydrocarbons(PAHs)and water-soluble inorganic ions(WSIIs)in PM_(2.5)in urban district and county of Suzhou City,and to know the health risks of PM_(2.5)to the local residents.Methods Ambient PM_(2.5)samples in the investigatedurban district and county of Suzhou city were collected from 10th to 16th every month from January 2018 to December 2022.The concentrations of PM_(2.5)and thetoxic components were detected by weighing method,ion chromatography and liquid chromatography,respectively.The pollution sources of PM_(2.5)were determined by the PMF model.And the health risks of PM_(2.5)were assessed by the recommended USA EPA model.Results The annual concentrations of PM_(2.5)in urban district and county of Suzhou City from 2018 to 2022 were 40.00μg/m^(3) and 43.00μg/m^(3),respectively,and their exceedance rates were 17.72%and 17.89%,respectively(both P>0.05).However,the concentrations of metal and metalloid and PAHs in PM_(2.5)in county were higher than that in urban district(P<0.05).The main pollution sources of PM_(2.5)in urban district were fossil fuel combustion and traffic emission,and the main sources of PM_(2.5)in county were fossil fuel combustion and industrial emission.The HQ values of PM_(2.5)-bound metal and metalloid in both urban district and county were all less than 1,with lower non-carcinogenic risk.The CR values of Cd,Pb and Ni were less than 1×10^(-6),which could be acceptable carcinogenic risk level for the local residents.However,the CR values of As and PAHs were greater than 1×10~(-6),with potential carcinogenic risk for the local residents.Conclusion Ambient PM_(2.5)pollution exists in urban and county areas of Suzhou City,but the main pollution source spectrum is different.Due to the potential carcinogenic risk for the local residents,the control measures of the main pollution sources of As and PAHs should be strengthened.