| In recent years,China’s rapid economic development and industrialization have made particulate matter pollution a serious environmental problem,as well as a significant load on human health.In this study,water-soluble ions（WSIIs）,carbonaceous substances（OC/EC）,trace heavy metals（HMs）in PM2.5and polycyclic aromatic hydrocarbons（PAHs）in indoor and outdoor dust were collected from rural areas and suburban areas of Taiyuan.The source analysis was combined with meteorological factors and relevant models,and the health risks of HMs in PM2.5 and PAHs in indoor and outdoor dust were evaluated.The main conclusions are as follows:（1）The annual average concentration of PM2.5（109.6±45.0μg/m~3）was approximately three times that of“Ambient Air Quality Standard（GB 3095-2012）”,and 1.7 times that of the non-heating season（147.5±54.7μg/m~3）;among them,WSIIs accounted for approximately46.0±11.1%,OC/EC 24.1±11.5%,and HMs 2.2%;the mass conservation calculations explain74-99%of their contribution,with SO42-,NO3-,NH4+and particulate organic matter accounting for about 60%,mineral dusts and EC for 15%,and elemental oxides,biomass combustion Cl-and coal combustion K+together account for about 10%.Local emissions dominate,with meteorological and geographical factors playing a key positive role.（2）Local heavy metal elements in PM2.5 have a high human health risk load for local residents.For carcinogenic risks,the carcinogenic risk values for children exposed to Cr in PM2.5 through direct intake and adults exposed to Cr through respiratory inhalation and dermal contact are above the acceptable threshold levels,and the carcinogenic risk values for children and adults exposed to Pb in PM2.5 through direct intake also exceed the risk thresholds;for non-carcinogenic risks,children and adults exposed to Mn in PM2.5 through respiration,children For non-carcinogenic risks,the non-carcinogenic risk values for children and adults for respiratory exposure to Mn in PM2.5,for direct intake exposure to Pb and for children exposed to Cr through direct intake were all higher than 1,indicating a strong non-carcinogenic risk.（3）The total concentration of 16 United States Environmental Protection Agency（USEPA）priority PAHs in outdoor dust ranged from 473.38 to 51766.35 ng/g（mean:9882.96 ng/g）.The total concentration of PAHs in the indoor dust ranged from 276.92 to 4026.84 ng/g（mean:1290.39 ng/g）.The PAHs in the outdoor dust were predominantly 5-ring PAHs,and in the indoor dust were predominantly 3-ring PAHs.The qualitative determination by Diagnostic Ratios（DRs）indicated that combustion sources were the main sources of PAHs in the dust at the sampling points in Taiyuan.The further quantitative analysis by Positive Matrix Factorization（PMF）indicated that outdoor dust was mainly from coal and coke sources,vehicle emissions and fossil fuel combustion;indoor dust is mainly caused by petroleum,coal combustion and biomass combustion,with contributions of 3.5%,14.7%and 81.8%respectively.（4）The health risk assessment showed that the total carcinogenic risk（CR）values ranged from 10-5 to 10-2,indicating a certain risk to humans and necessary risk management must be carried out in a timely manner.Depending on the route of exposure,the lifetime incremental carcinogenic risk（ILCR）via dermal contact,ingestion,and inhalation are 1.72×10-5-1.22×10-3,1.08×10-5-8.81×10-4,and 2.68×10-10-5.35×10-8,respectively.Inhalation of dust particles through breathing is almost negligible compared to the other two exposure routes.In addition,the carcinogenic risk of dermal and respiratory inhalation of PAHs was higher in adults compared to children,while the ILCR values for the ingestion route were slightly higher in children than in adults. |
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