Chemical component characteristics and source analysis of PM2.5 in Jinchang City
In order to study the characteristics of PM2.5 and its chemical components(organic carbon,elemental carbon and water-soluble ions)in Jinchang City,manual sampling of atmospheric PM2.5 in Jinchang City was conducted from May 2020 to March 2021,and the PMF model and HYSPLIT model were used to analyze the sources of pollution.The results showed that the annual average mass concentration of PM2.5 was(62.2±10.4)μg·m-3 in Jinchang during the observation period,and the average mass concentration of PM2.5 was in spring,winter,autumn and summer from high to low.The chemical mass closure study shows that the carbon component(OM+EC)is the main component of PM2.5 in Jinchang.The average annual mass concentrations of OC and EC in PM2.5 were(13.4±5.6)μg·m-3 and(2.9±1.5)μg·m-3,respectively.TC accounted for 16.3％of PM2.5 mass concentration,and the average values of OC/EC in four seasons were greater than 2,indicating that secondary pollution existed in each season during the sampling period.The correlation coefficient between OC and EC in summer was the lowest,indicating that the pollutant sources in summer were more complex than in other seasons.The average annual mass concentration of total water-soluble ions in PM2.5 in Jinchang City is(25.0±11.6)μg·m-3,accounting for 40.2％of PM2.5 mass concentration,in which SO42-、Ca2+、NO3-and Cl-are the four main ions.They accounted for 22.5％,17.1％,16.8％and 12.1％of total ions respectively.The ion balance analysis of water-soluble ions showed that the correlation of canion in summer,autumn and winter was good,and there was no important ion deletion,while in spring it was poor,and there was important anion deletion.The PMF model showed that the main pollution sources of PM2.5 in Jinchang were combustion sources(biomass+coal)(34.4％),soil dust(25.2％),secondary inorganic aerosol(22.6％)and motor vehicle exhaust(18.0％).The HYSPLIT model showed that the PM2.5 concentration in Jinchang in spring was greatly affected by the input of external pollution sources.Summer,autumn and winter should mainly consider the contribution of local emissions.
PM2.5chemical compositionsource analysisJinchang City
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NSTL
万方数据
