Characteristics Of Toxic Elements In PM_2.5 During Pollution In Jinan

With the acceleration of urbanization and industrialization,atmospheric environment has become a hot issue.As the primary pollutant affecting air quality,PM2 5 is easy to enter the human body and have an impact on health.Toxic elements is the important components of PM2.5,may lead to ischemic heart disease,lung cancer and chronic obstructive pulmonary disease when exceed the permissible dose.Therefore,in order to control the content of toxic elements in the atmosphere,it is necessary to analyze their characteristics and sources.In this study,the normal pollutants and toxic elements in PM2 5 were monitored in the central campus of Shandong University for one year from January 2017 to January 2018.PM2 5 samples were collected and analyzed by ICP-MS for the concentration of 6 toxic elements including V,Cr,Ni,As,Cd and Pb and other related elements.The positive matrix factorization(PMF)and health risk model were used to analyze the sources and potential health risks of toxic elements in PM2.5.During pollution,PM2 5 is the main pollutant.This is high annual average level of PM2 5 in Jinan,which is as twice as it is in China.The concentration of Cr in PM2.5 exceeds the limits set by China,WHO and the European Union.The average concentrations of toxic elements in polluted weather was 1.5-2.3 times of the annual average.In the process of pollution events,the concentrations of toxic elements in different pollution events were significantly different.In the pollution event from January 15 to 21,2018,PM2.5 concentration after the pollution event return to the level before the pollution event,while the concentration of toxic elements was 14%to 147%higher than that before the pollution event,indicating that the accumulation of toxic elements may be related to the wind direction.The source analysis with PMF shows that the toxic elements in the heavy pollution state and the whole sampling period are mainly from four sources,respectively coal combustion source(45.7%;39.1%),industrial sources(8.5%;22.1%),traffic source(31.1%;13.8%)and dust(14.7%;25.0%).Toxic elements mainly come from coal burning source and traffic source.Health risk analysis showed that manual-oral contact was the main exposure way.Toxic elements have no non-carcinogenic risk for adults and children except Pb exposure for children.The analysis of the incremental lifetime cancer risk showed that the cancer risks caused by Ni and As for children which exceeded the acceptable range.The total ILCR values of adults and children were 1.21 e-04 and 2.80 e-04,respectively,which exceeded the acceptable range,indicating that the incremental lifetime cancer risks in Jinan were large.The analysis shows that after years of atmospheric treatment,the concentration of toxic elements in Jinan is significantly lower than that in previous years.The concentration level of toxic elements in Jinan is higher than that in developed countries and lower than that in domestic cities.However,there are still health risks.