| With the increasingly severe air pollution situation and people's growing ecological environment needs in China,it is imperative to carry out the air pollution prevention and control strategies in each city,atmospheric PM2.5 has been the primary air pollutant in most Chinese urban areas in recent years,therefore,it is important to understand pollution characteristics and pollution sources of PM2.5 to further implement the air pollution control action plan in each city.In this study,we selected three PM2.5 sampling sites where they located in residential area,traffic area and industrial area in Hengyang,84 PM2.5 samples were collected at three sampling sites and four seasons from December 2015 to September 2016,then the mass concentrations of 14 metal elements?Pb,Cd,Cu,Cr,Ni,Fe,Zn,Mn,K,Ca,Mg,Al,As,Hg?in PM2.5 were measured by inductively coupled plasma mass spectrometry?ICP-MS?and atomic fluorescence spectrometry?AFS?,finally,we analyzed the seasonal and spatial pollution characteristics of atmospheric PM2.5 and 14metal elements in PM2.5,we discussed the health risks of 9 heavy metals in PM2.5 and pollution sources of atmospheric PM2.5 in Hengyang.The main results indicated that:?1?The mass concentrations of PM2.5 in Hengyang ranged from18.10?g·m-3 to 325.72?g·m-3 during the sampling period,the average mass concentration of PM2.5 was 89.65?g·m-3,and the PM2.5 pollution concentration followed the order of spring>winter>autumn>summer and industrial area>traffic area>residential area.?2?The sum of mass concentration of 14 metal elements in 84PM2.5 samples was 11.89?g·m-3,which accounted for 13.26%in PM2.5,and Ca,Al,K,Fe,Mg were major pollution compositions in PM2.5,the sum of mass concentration of those metal elements accounted for 85.03%of all measured metals in this study.Heavy metals Pb,Cd,As in PM2.5obviously exceeded the secondary annual limit values of National Ambient Air Quality Standards.?3?The non-carcinogens?Pb,Cu,Zn,Mn,Hg?and potential carcinogens?Cd,Ni,As?in PM2.5 through breathing at three different urban areas would not be harmful to human healthy,but there was little potential carcinogenic risk of heavy metal Cr for permanent residents in industrial area.The health risk indexes of 9 heavy metal elements all followed the order of adult male>adult female>children and adolescent,and industrial area>traffic area>residential area.?4?Pollution sources of 14 metals in PM2.5 in Hengyang were explored by using enrichment factor?EF?,principal component analysis?PCA?,and positive matrix factorization?PMF?receptor model,there were better consistency of three receptor models results.Finally,four pollution sources and source contribution rates of PM2.5 were analyzed,it were non-ferrous metal smelting?72.9%?,fossil fuel combustion?13.4%?,steel production?7.5%?and vehicle exhaust emissions/dust?6.2%?,respectively. |
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