中国地质大学(武汉)环境化学05AirPollution

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1、ChapterFiveAirPollution:TroposphericOzone,InorganicGaseousPollutants,Particles1.TroposphericOzoneGoodOzoneandBadOzoneTwotypesofairpollutants:primaryvs.secondaryFormationofozoneNecessaryingredientsforozoneformationFormationofoxidantsotherthanO3Photochemicalsmog

2、PhotochemicalairpollutionControlstrategiesforozoneGoodOzoneandBadOzoneStratosphericozoneprotectlivesonEarthfromharmfuleffectsofUVradiation.Troposphericozone:Causingrespiratorydistressandeyeirritation（呼吸困难和眼睛刺激）DestroyingplantsProducingcracksinrubberOzoneisastr

3、ongoxidant,reactswithmoleculescontainingC=Cdoublebonds,formingepoxides（环氧化物）.Twotypesofairpollutants:primaryvs.secondaryPrimarypollutants:releaseddirectlyfromsourcesExamples:CO,SO2,NOxSecondarypollutants:formedthroughchemicalreactionsoftheprimarypollutantsandt

4、heconstituentsoftheunpollutedatmosphereintheair.Example:O3FormationofozoneNO2+hvNO+O(1)O+O2+MO3+M(2)NO+O3NO2+O2(3)NO2+hvNO+O(1)O+O2+MO3+M(2)HO2.+NONO2+OH(4)RO2.+NONO2+RO.(5)NonetO3formationO3isformedNetof(1)+(2)+(4):RO2.+O2O3+RO.NO2iscapableofabsorbing

5、visiblelight(<400nm)toproduceO.？SourcesofRO2.:OxidationofhydrocarbonsAsingleorganicradicalcanproducemanyperoxyradicalsbysuccessiveroundsofO2combinationandfragmentation.RH+OHR.+H2OR.+O2RO2.hydrocarbonsExample:OxidationofcarbonmonoxideCO+.OH+O2CO2+HO2.HO2.+NO

6、NO2+.OHNO2+hvNO+OO+O2+MO3+MNet:CO+2O2+hvCO2+O3ThenetreactioncanbeviewedasacatalyticoxidationofCOtoCO2.NetformationofO3occurs.Example:OxidationofmethaneCH4+.OH+O2CH3OO.+H2OCH3OO.+NOCH3O.+NO2CH3O.+O2HCHO+HO2.HO2.+NO.OH+NO2NO2+hnNO+O(2x)O+O2+MO3+M(2x)Ne

7、t:CH4+4O2HCHO+H2O+2O3Thenetreactionisthatforeachmoleofmethaneoxidized,2molesofO3isproduced.NecessaryingredientsforozoneformationSunlightNOx(NO,NO2)Hydrocarbons(VOCs:volatileorganiccarbon)VOCs+NOx+hnO3+otherpollutantsProductionofOatomProductionofRO2,whichreac

8、tswithNOsothatO3couldaccumulate.VOCsCH4+.OH+O2CH3OO.+H2OCH3OO.+NOCH3O.+NO2CH3O.+O2HCHO+HO2.HO2.+NO.OH+NO2NO2+hnNO+OO+O2+MO3+MNet:CH4+4O2HCHO+H2O+2O3VOCsSunlightFormationofox