| The air pollution in Guanzhong Area is severe and the haze weather is frequent.It is a vital area for air pollution prevention.In this study,five sampling points?XA,WN,BJ and XY?were set up at five major cities in Guanzhong Area?Xi'an,Weinan,Tongchuan,Baoji,and Xianyang?from September 2017 to January 2018.This paper analyzes the temporal and spatial variation characteristics of PM10 and PM2.5 and water-soluble ionic components in atmospheric particulates.And use PMF model to analyze the sources of water-soluble ionic component pollution.It is expected to provide scientific evidence for air pollution control in Guanzhong effective data support.The results showed that the average concertrations of PM10 and PM2.5 in GuanzhongArea during the sampling period respectively were 121±85?g/m3 and 89±?g/m3,and the main pollution was PM2.5.The overall spatial distribution of PM10 and PM2.5 shows that in central of Guanzhong Area is serious and pollution in surrounding cities is relatively light.In the heating season,the concentration of pollutants increased significantly,which is mainly related to the reduction of the atmospheric boundary layer,frequent stable wather and pollutants emitted by urban heating during the heating period.The sources of PM10 and PM2.5 at different points are similar,but there are significant differents between the points due to different pollution sources.The average concentrations of water-soluble ions in PM10 in Guanzhong Area at autumn and winter were 43.279±25.381?g/m3 and 50.136±32.79?g/m3,and theAverage concentrations of water-soluble ions in PM2.5 were 27.783±14.923?g/m3 and34.049±21.73?g/m3.It showed that the content of water-soluble ions is higher in PM2.5.The spatial distribution of water-soluble ions is the same as that of particulate matters,which is related to the distribution of pollution sources in Guanzhong Area.The correlation between the anion equivalent concentration and the cation equivalent concertration in the water-soluble ions is well,and AE/CE<1.The water-soluble ions are generally alkaline.The average secondary ions(SNA,SO42-,NO3-and NH4+)concentrations in PM10in Guanzhong Area at autumn and winter were 22.161±13.162?g/m3 and 23.124±15.264?g/m3,and the average SNA concentrations in PM2.5 were 15.19±7.269?g/m3and 17.304±10.788?g/m3.It showed that the content of SNA is higher in PM2.5.Concentration of SO42-in PM10 in the Guanzhong Area showed the characteristics of light pollution in central area and serious pollution in surrounding area.Except for Xianyang and Tongchuan,NH4+is less polluted.NO3-in PM10 and PM2.5,SNA in PM2.5.5 were both heavily polluted in central region and lightly polluted in surrounding regions.NH4HSO4and NH4NO3 in Guanzhong Area are the main SNA bonding ways.According to the ratio of NO3-and SO42-,it is preliminarily judged that the main pollution source during the non-heating period in Guanzhong Area is a fixed sources,and the main pollution source during heating period is mobile sources.The results of PMF model showed that the pollution contribution sources of water-soluble ionic components in PM10 are biomass combustion sources,coal-fired pollution sources,motor vehicle pollution sources,and soil dust pollution sources.Among them,coal-fired pollution,motor vehicle pollution and dust pollution highly affect Guanzhong Area.The contribution ratio to water-soluble ions in PM10 reached more than 90%.The sources of water-soluble ionic components in PM2.5 are mainly soil dust sources,biomass combustion sources,secondary sources and coal-fired sources.The higher proportion of water-soluble ions in PM2.5 is secondary pollution and coal-fired pollution reached more than 70%. |
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