| In recent years,with the rapid development of Chinese economy and the continuous advance of urbanization,frequent regional haze incidents aroused great public concern.Atmospheric aerosols have a very serious impact on climate,environment and human health.Haze occurred frequently in Beiji ng-Tianjin-Hebei region.And it was meani ngful to study the physical and chemical characteristics and the sources of atmospheric particulate matter in Beiji ng-Tianj in-Hebei region.In order to study the pollution level and sources of metal elements in the fine particles of Beiji ng-Tianj in-Hebei region,the study used the flow sampler TH150C(China,Tianho ng)to collect PM2.5 samples in Beiji ng,Tianjin,Shijiazhua ng,Xia nghe and Xi nglo ng from 2014 to 2015.PM2.5 samples were prepared by microwave digestion.The concentration of 16 elements in PM2.5 was analyzed by Inductively Coupled Plasma Mass Spectrometry(ICP-MS)to study the time and space distribution.The average concentration of metal elements in PM2.5 was as follows:Ca>K>Fe>Al>Mg>Zn>Pb>Cu>Mn>As>Cr>Se>V>Cd>Co>Ag.The main metal elements(Ca,K,Fe,Al and Mg)accounted for more than 90%of measured elements.Pollution from man-made sources and crustal sources were more serious in Shijiazhua ng than it in Beiji ng.And Tianjin was mainly manifested as serious pollution of man-made sources.Compared with the Xi nglo ng,Shijiazhua ng and Xia nghe is more serious for man-made pollution.The measured elements in PM2.5 of Beiji ng-Tianjin-Hebei region gradually increased from clean days to haze days.However,the proportion of metal elements in PM2.5 decreased from 7%-12%to 3%-4%.With the increasi ng of PM2.5 pollution,the concentration of crustal source increased slowly,while the pollution element increased higher.The concentration of measured elements in winter and spri ng is higher than it in summer and autumn.The seasonal variation of metal elements in Shijiazhua ng was most obvious,and the total element concentration in spri ng was 3.2 times of that in summer.The concentrations of the crustal elements such as Mg,Al,Ca and Fe in spri ng were much higher than those in other seasons,same as the trend of its proportions in PM2.5.The concentrations of Cu,Zn,As,Se,Ag,Cd and Pb showed the trend of that winter and autumn is more than summer and spri ng.Coal-related elements such as Se,As,Cd and Pb were highest in winter.Mg,Al,K,V,Mn,Fe and Co in PM2.5 were from the crustal source.And Cu,Se,Ag,Cd and Pb in PM2.5 were from the man-made source.The enrichment degree showed as Shijiazhua ng>Xia nghe>Tianjin>Beiji ng>Xi nglo ng.Sources of measured metal elements in Beiji ng were coal combustion,combustion and industrial emissions,dust,traffic sources.The contribution of the sources were 36.2%,26.9%and 12.0%.Sources in Tianjin were ground dust,coal combustion,combustion and industry,traffic sources.The contribution of the sources were 37.8%,24.3%and 17.2%.Sources in Shijiazhua ng were dust,coal and industrial,traffic.The contribution of the sources were 36.8%,23.9%and 11.8%.Sources in Xia nghe were coal,combustion and industry,dust,traffic sources.The contribution of the sources were 34.1%,23.8%and 16.7%.Sources in Xi nglo ng were coal combustion,combustion and industry,soil dust,buildi ng dust,traffic sources.The contribution of the sources were 29.1%,20.9%,19.0%and 8.3%. |
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