Study on variation characteristics of PM2.5 mass concentrations in Beijing after the action on comprehensive control of air pollution

BasedonthedataofthePM2.5massconcentrationsfromthemonitoringpointattheUSembassyinBeijingfrom2013to2017,thecharacteristicsofPM2.5 massconcentrationanditscorrelation withthe mass concentrations of NO2 and SO2 in Beijing in the past five years are analyzed.The emphasisisfocusedonthevariationcharacteristicsofPM2.5aftertheactiononcomprehensivecontrolof airpollutionimplementedintheautumnandwinterof2017,whichisaimedattheemissionreduction frombanningofuncontrolledcoalcombustion.TheresultsshowthattheannualaverageofPM2.5 mass
concentrationin Beijing has decreased yearly since 2013,and the decreasing range of the annual averagein2017hasreached50%.AnalysisofdataindifferentseasonsshowsthatthePM2.5massconcentrationinwinteristhehighest,followedbyautumn,spring,summerindescendingorderin2013to 2016.However,aftertheactiononcomprehensivecontrolofairpollution,itisnoticedthatthemass concentrationofPM2.5inwinter2017waslowerthanthatinautumnandspring,approachingthelevel ofsummer.Inaddition,comparedwiththepastyears,themassconcentrationsofNO2andSO2intheair alsodecreasedsignificantlyinwinter2017,inwhichthedecreaseofSO2massconcentrationismoreobvious.Theseresultsshowthattheemissionfromburningcoalshasbeeneffectivelycontrolledafterthe actiononcomprehensivecontrolofairpollution.Finally,thecorrelationanalysisshowsthatthemass concentrationsofPM2.5hasasignificantpositivecorrelationwiththoseofSO2,indicatingthatcountermeasuresforthebanningofuncontrolledcoalcombustionsuchas“coalsreplacedbygas”and“coals replacedbyelectricity”haveanobviouseffectonreducingthePM2.5emission.