Analysis Of Elemental Pollution Characteristics And Health Risk Assessment Of PM_2.5 In Different Cities

The International Agency for Research on Cancer classifies particulate matter?PMs?as the first class of human carcinogens.Atmospheric fine particulate matter(PM_2.5)is a mixture in which the heavy metal elements As,Cd,Ni and Cr belong to the first class of carcinogens,while Pb,Co and Mn are the second class.In this study,we collected PM_2.5 in four cities in Taiyuan,Beijing,Hangzhou and Guangzhou,and analysised the inorganic elements by ICP-MS and ICP-OES.The discrete coefficients are used to analyze whether there are significant differences in the elements between different cities in the same city and in the same season.The enrichment factor and principal component analysis are used to analyze the source of inorganic elements.Non-carcinogenic and carcinogenic risk assessments for children,adult males and adult females by a health risk assessment model;potential ecological risk assessments of metallic elements are carried out by ecological risk assessment models.The results are as follows: 1.For different seasons in the same city: the four cities have significant differences in summer and winter.In addition,the autumn and winter of Taiyuan,the spring and winter of Beijing,the spring and winter of Hangzhou,and there are also significant differences in the autumn and winter of Guangzhou.For different cities in the same season: in summer and winter,there are significant differences between the three cities?Beijing,Hangzhou,Guangzhou?and Taiyuan.In addition,in spring,Hangzhou and Taiyuan,as well as Guangzhou and Taiyuan,also showed significant differences.2.In the four seasons of PM_2.5 in four cities,the EF values of the elements Zn,Cd and Sn are all greater than 10,and there are different degrees of enrichment.Element Mo,only in the four seasons of Taiyuan City,the EF value is greater than 10,and is extremely strong enrichment;the element Ni,only in the winter of Guangzhou,the EF value is greater than 10,and shows extremely strong enrichment.3.The source of PM_2.5 in Taiyuan City is mainly dust,industrial source and biomass burning;followed by coal burning and motor vehicle emissions.The main sources of PM_2.5 in Beijing are fuel,biomass burning and vehicle exhaust emissions;followed by industrial emissions and dust.The main sources of PM_2.5 in Hangzhou are fuel,coal,biomass burning,motor vehicle exhaust and industrial sources;followed by dust and so on.The main sources of PM_2.5 in Guangzhou are industrial sources,metal smelting,coal burning and dusting;followed by emissions from motor vehicles and biomass burning.4.PM_2.5 heavy metals do not have non-carcinogenic risks and cancer risk in four cities in four seasons.5.The total potential ecological value of the four seasons of the four cities is greater than 320,indicating that there is a serious ecological hazard.Among them,the main contribution factors of the potential ecological risk index RI are the elements Pb and Cd.Through the analysis of pollution characteristics and risk assessment of elements in PM_2.5 of four cities,it provides a theoretical basis for establishing priority control pollutants and key prevention and control targets in air pollution prevention and control in relevant areas.