| In recent years,with the rapid development of China's economy and the steady improvement of the level of industrialization,the problem of air pollution has become increasingly serious,which has caused widespread concern in the society.The environmental pollution problem of fine particulate matter as the main pollutant has become the top priority of environmental governance,especially in Beijing-Tianjin-Hebei(BTH)region.PM1,as a typical representative of ubmicron fine particle,could gather a large number of pathogens and toxic and harmful substances,enter the human body through the respiratory system,and bring a huge threat to human health.In addition,when it is in adverse weather conditions,fine particles in the atmosphere are easy to accumulate rapidly,form serious haze events,and significantly reduce the visibility of the atmosphere,which has an important impact on people's daily activities and transportation.Therefore,it is of great significance to carry out the research on the pollution characteristics of fine particles in the atmosphere,to analyze the main factors affecting the visibility of the atmosphere and to obtain the influencing factors of haze,so as to further improve the environmental quality and protect human health.In this study,PM2.5 and PM1 samples were collected in Beijing,Tangshan and Shijiazhuang.The mass concentrations of PM2.5 and PM1 and their components were tested and analyzed to obtain the pollution characteristics of fine particles in typical cities.Based on the aerosol particle size spectrometer,the particle size of fine particles in Beijing was continuously observed to obtain the distribution characteristics of particle number concentration,surface area and volume during the haze and non-haze periods in different seasons.Based on the"2+26"urban air pollution source emission inventory in 2017 and the research results of high-resolution air pollution source emission inventory of BTH region in 2016 by the research team,combined with the PM2.5 and PM1 emission ratio in typical industries,the PM1 emission inventory of typical regional air pollution sources was established.On this basis,the receptor model and WRF-CMAQ numerical model were used to analyze the source of fine particulate matter,and the source analysis results of fine particles in the atmosphere are obtained.Based on the air quality data and meteorological observation data,Statistical Product and Service Solutions(SPSS)software is used to analyze the correlation,principal component analysis and multiple linear regression analysis of the concentration and components of fine particles in the atmosphere and the impact of meteorological elements on the visibility of the atmosphere,so as to determine the influencing factors of haze.The results showed that the mass concentrations of PM1and PM2.5 in Beijing,Tangshan and Shijiazhuang,was higher in autumn and winter than that in spring and summer.In winter,the mass concentrations of PM1and PM2.5 in Shijiazhuang were 2.28 and 2.30 times of that in Beijing,1.35and 1.51 times of that in Tangshan,respectively,suggesting the serious pollution of fine particles in Shijiazhuang.Based on the calculation results of PM1 emissions from air pollution sources,Beijing's annual PM1 emissions in 2017 were 12500 tons,which was 1.78%of the total PM1emissions in Beijing Tianjin Hebei region.The total PM1emissions from dust sources and mobile sources in Beijing accounted for 72.02%,which was the main source of PM1 emissions in Beijing.However,the main sources of PM1 emissions in Shijiazhuang,a typical industrial city nearby,were fossil fuel fixed combustion sources and process sources,which accounted for 53.57%and 18.69%of the total PM1 emissions in Shijiazhuang,respectively.The results of source analysis of fine particles showed that mobile sources are the main contribution sources of fine particles(PM1and PM2.5)in Beijing.The contribution range of mobile sources in PM1and PM2.5 in each season is33.34%?38.23%and 44.67%?49.21%,respectively.The main contribution sources of Shijiazhuang were fixed combustion sources of fossil fuels,which accounted for 30.16%?37.46%and23.98%?32.26%,respectively.The results of particle size analysis during the haze and non-haze periods in different seasons in Beijing showed that the number concentration,surface area and volume are mainly distributed in the particle size segment below 1?m,and their values were the highest in autumn and winter,followed by spring,and summer.The peak particle size segment of the number concentration of particles is concentrated in 0.255-0.271?m.Based on SPSS,correlation analysis,principal component analysis and multiple linear regression analysis of the concentration and components of fine particles,meteorological elements(relative humidity and wind speed)and atmospheric visibility were carried out.The results showed that the highest correlation with atmospheric visibility is PM1,and the correlation coefficient was-0.729.By establishing multiple regression model and verifying the simulation effect of atmospheric visibility in Beijing's haze weather,the results show that the maximum correlation coefficient between the simulation value and the monitoring value is 0.80,and the NMB and NME are-7.24%and 14.33%respectively.Affected by the difference in the mass concentration of meteorological elements,PM1 and its components,the simulation results of atmospheric visibility in tangshan and shijiazhuang were relatively poor,with the highest correlation coefficient of tangshan being 0.71,the highest correlation coefficient of NMB and NME being 5.56%and 24.39%,and the highest correlation coefficient of shijiazhuang being 0.75,and the highest correlation coefficient of NMB and NME being 8.26%and 15.79%,respectively.The above results indicated that the atmospheric visibility under the haze weather was affected by the atmospheric fine particulate matter,the component mass concentration and the meteorological factors comprehensively,and the influences on different cities were different. |
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