| In recent years,China's society and economy have developed rapidly.With the sharp rise in energy consumption,the problem of particulate pollution has become increasingly serious.Smog weather frequently occurs in some cities in China,which has attracted extensive attention from the government and scholars at home and abroad.Jiuquan City,Gansu Province is located in Hexi Corridor,where there are many dusty weather.In addition,with the increase of industrial enterprises in recent years,particulate pollution has been aggravated.Therefore,the research on the pollution characteristics of PM10 and PM2.5 and the source analysis can provide scientific basis for the scientific prevention and effective management of atmospheric particulate pollution in Jiuquan City,which is of great significance.In this study,three sampling points were set up in Jiuquan's bustling area,high-tech zone and suburban area.PM10 and PM2.5 samples were collected in four seasons from 2019 to 2020by using the medium-flow atmospheric active sampler.The concentration levels of PM10 and PM2.5 and some inorganic elements?Mg,Al,Ca,Fe,Zn,Cu,Pb,Cr,Mn,Cd,Ni,Ba,As,Co,Se,V?were measured,and the pollution characteristics were analyzed in terms of time and space.Using correlation analysis to determine the relationship between inorganic elements,and enrichment factor analysis was used to determine their source types.Finally,using principal component analysis and PMF model to determine the possible sources of inorganic elements in PM10 and PM2.5 and the contribution rates of various pollution sources.?1?The daily variation of PM10 and PM2.5 concentrations in Jiuquan city is relatively stable in the four seasons,with the concentration increasing in case of sand-dust weather and decreasing in rainfall and snowfall.The daily concentration of particulate matter in the four seasons all reached the second standard limit of 24-hour average concentration.The seasonal variation of PM10 and PM2.5 concentrations is spring>autumn>winter>summer.The variation regularity of PM2.5 in suburbs is different,which is winter>autumn>spring>summer.The annual average concentration of PM2.5 in Jiuquan City is 34.4?g/m3,reaching the secondary standard.The annual average concentration of PM10 is 78.1?g/m3,which has been greatly reduced compared with the previous.?2?The seasonal variation of Mg,Al,Ca,Fe and other crustal elements in atmospheric PM10 in Jiuquan city is spring>autumn>summer,which is related to large sandstorms in spring and autumn and heavy rainfall in summer.The variation of Zn,Mn,As and Cd concentrations is autumn>spring>summer,which is related to straw burning in autumn.The concentration of other elements changed steadily in the three seasons without obvious difference.The seasonal variation of Mg,Al,Ca and Fe in PM2.5 is autumn>spring>summer,which indicates that the above four elements in PM2.5 in autumn have other sources than dust.The change rule of Zn,Pb,As and Cd is autumn>summer>spring,which is related to a large amount of straw burning in suburban areas in autumn,a large amount of motor vehicle traffic in summer and a large amount of building dust.Other elements have no obvious seasonal variation characteristics.?3?Based on the results of correlation analysis,enrichment factor analysis,principal component analysis and PMF analysis of elements in PM10 and PM2.5 in three seasons,it is finally determined that inorganic elements in PM10 in spring mainly come from motor vehicle emissions and road dust sources,coal and straw combustion sources,metal smelting sources and soil dust sources.The contribution rate of each pollution source is 9.39%,3.33%,29.45%,57.83%.Inorganic elements in PM2.5 in spring mainly come from garbage incineration sources,metal smelting sources,soil dust sources,motor vehicle emissions and road dust sources,coal combustion and straw combustion sources.The contribution rate of each pollution source is 7%,2.71%,55.43%,13.51%,21.35%.Inorganic elements in PM10 in summer mainly come from soil dust and garbage incineration sources,road dust and motor vehicle emission sources,coal combustion sources,metal smelting sources and building dust sources.The contribution rate of each pollution source is 57.22%,6.27%,2.7%,3.23%,30.58%.Inorganic elements in PM2.5 in summer mainly come from coal-fired sources,road dust and motor vehicle emission sources,garbage incineration sources,mixed sources of soil dust and construction dust,and metal smelting sources.The contribution rate of each pollution source is 4.42%,17.13%,1.85%,62.44%,14.15%.Inorganic elements in autumn PM10 mainly come from road dust and motor vehicle emission sources,coal burning sources,soil dust sources,garbage incineration sources,straw combustion sources and metal smelting sources.The contribution rate of each pollution source is 24.7%,4.48%,36.43%,11.14%,6.84%,16.42%.Inorganic elements in autumn PM2.5 mainly come from garbage incineration sources,straw combustion sources,soil dust sources,metal smelting sources,coal combustion sources,road dust and motor vehicle emission sources.The contribution rate of each pollution source is 10.9%,11.71%,28.84%,8%,24.76%,15.8%. |
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