Chemical Characterization And Source Apportionment Of PM_2.5 From 2017 To 2018 In Xinxiang

Xinxiang is located in the northern part of Henan Province.It is both a city on the Beijing-Tianjin-Hebei transmission channel and one of the core cities in the Central Plains Economic Zone,with serious particulate pollution.The study of characteristics of atmospheric PM_2.5 components and pollution sources in Xinxiang can provide the basis for the formulation of air pollution prevention and control measures.In this study,from December 2017 to November 2018,PM_2.5 samples were collected in typical months in four seasons.Considering that winter pollution was the most serious,PM_2.5samples was also collected in the winter of 2018.PM_2.5 mass concentration and its chemical composition were analyzed,and positive matrix factorization method?PMF?and potential source contribution function?PSCF?were used for source analysis.In addition,carcinogenic risks and non-carcinogenic risks of toxic elements in PM_2.5 were evaluated.The main conclusions are as follows:The characteristics,source analysis and health risk assessment results of PM_2.5components from the winter of 2017 to the autumn of 2018 showed that:?1?The average PM_2.5 concentration was 71.6?g/m³,with the highest seasonal mean value in winter and the lowest in summer.The TC,water-soluble inorganic ions?WSIIs?,and elements in PM_2.5 accounted for 19.2%,57.5%,and 8.7%,respectively.The sum of the concentrations of NH₄⁺,NO₃^-and SO₄^2-accounted for 88.9%of the WSIIs.The sum of Na,Mg,Al,Si,Ti,Ca,Mn,and Fe accounted for 53.6%of the total elements.?2?The PMF source analysis showed that secondary aerosols?41.2%?,coal combustion?18.1%?,vehicle traffic?16.8%?,dust?10.7%?,industrial processes?7.2%?and biomass burning?6.0%?were the main sources of PM_2.5.Backward trajectory cluster analysis showed that the long-distance transmission from the northwest and the short-distance transmission in the surrounding areas of Xinxiang have a great impact on PM_2.5,and secondary aerosols,coal combustion and vehicle traffic were the major sources of transmission pollution.PSCF indicates that the surrounding areas of the sampling site were PM_2.5 major potential source areas.?3?The carcinogenic and non-carcinogenic risks of toxic elements?except V?to children and adults through intake pathway exposure were the greatest,and the carcinogenic and non-carcinogenic risks of children through intake pathway and dermal exposure were greater than those of adults.As and Ni pose a serious potential carcinogenic risk to both children and adults.As poses a significant non-carcinogenic risk to children and adults,and Pb to children.The comparison of PM_2.5 component characteristics,source analysis and health risk assessment results in winter of 2018 and 2017 showed that:?1?The concentration of PM_2.5 in winter of 2018 was 88.5?g/m³,which was decreased from that in winter of2017,but the concentration and proportion of organic carbon increased.?2?The PMF source analysis results showed that the contributions of secondary aerosols,coal combustion,vehicle traffic were all large in the winter of 2017 and 2018.The proportion of dust in the winter of 2018 was smaller than that in the winter of 2017,while the proportion of vehicle traffic increased.Backward trajectory cluster analysis showed that the air mass from northwest has a great influence on PM_2.5.The transmission of secondary aerosols,coal combustion and vehicle traffic contribute more.PSCF showed that the surrounding sampling sites,Zhengzhou and Kaifeng were the main potential source areas.?3?The risk value of all elements?except Pb?to the human body through three different exposure pathways in the winter of 2018 was less than that in the winter of 2017.In the winter of 2017,As and Ni had potential carcinogenic risks for children and adults,As for children and adults,and Pb for children had non-carcinogenic risks.In winter 2018,As for children and adults had a potential carcinogenic risk,while As and Pb for children had a non-carcinogenic risk.