资源描述：
《大学化学课件5对流层大气化学反应及光化学烟雾英文精编整理》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、Section5ChemicalreactionintroposphereAssortofatmosphericconstituents(1)Semi-permanencegas,suchasN2,Ar,Ne,Kr,Xe(2)Alterableconstituents,suchasCO2,CH4,H2,N2O,O3,O2(3)Intensivealterableconstituents,suchasH2O,CO,NO,NH3,SO2,HC,H2S.Accordingtolifetime,atmosphericconstituentsaredi
2、videdintothreeassorts.Cleanatmosphericconstituentsintroposphereisshownintalbe1.Carbondioxidehasbeenincreasinginconcentrationduringthiscentury,mostlythroughtheburningoffossilfuelssuchascoalandpetroleumproducts.Traceconstituentsmayvaryinconcentrationindifferentpartsoftheatmos
3、phereandindifferentpartsoftheglobe.2.Gaseousconstituentsoftheatmosphere3.SourceandcollectionofatmosphericconstituentsandgaseouscirculationThesubstanceexchangeortransformofatmosphericconstituents,amongatmosphere,aquaticsphere,soilsphere,andbiologicalsphere,arecarriedoutconti
4、nuously.Thisiscalledgaseouscirculation.Theprocesstoproducegasesiscalledsourceofgases.Itincludeschemicalprocess,biologicalactivity,volcano,andfossilfuelscombustion.Theprocesstoremovegasesiscalledcollectionofgases.Itincludeschemicalprocess,biologicalactivity,andphysicalproces
5、s.4.Importantlightabsorptionsubstances4.1lightabsorptioncharacteristicofNO2NO2＋hγ(λ≤420nm)→NO＋O（3P）O（3P）+O2+M→O3PhotolysisNO2ofisonlyartificialsourceofO3introposphere.入＜380nmφNO≈1入=405nmφNO≈0.36入>420nmφNO≈04.2PhotolyticreactionofO3,HNO2,andH2O2O3+hγ(λ≤320nm)→O(1D)+O2O(1D)＋H
6、2O→2OHHONO＋hγ(λ＜400nm)→OH＋NOH2O2＋hγ(λ＜360nm)→OH＋OH4.3PhotolyticreactionofHCHOandCH3CHOHCHO＋hγ→H＋HCOH＋O2＋M→HO2HCO+O2→HO2+COCH3CHO＋hγ→CH3＋HCOCH3＋O2＋M→CH3O2HCO+O2→HO2+COformaldehydeacetaldehydeO3+hγ(λ≤320nm)→O(1D)+O2O(1D)＋H2O→2OHInpollutionatmosphere,thefollowingphotochemicalr
7、eactionismoreimportant.HONO＋hγ(λ＜400nm)→OH＋NOH2O2＋hγ(λ＜360nm)→OH＋OHOnaverage,theconcentrationoffreeradicalOHis7*105／cm3ontheglobe.Seventimestentothepoweroffive5.Freeradicalinatmosphere5.1SourceoffreeradicalOHcubiccentimetre5.2SourceoffreeradicalHO2Photolysisofformaldehydean
8、dacetaldehydeinatmosphere:HCHO＋hγ→H＋HCOH＋O2＋M→HO2HCO+O2→HO2+COHCHO＋NO3→HNO3＋HCOHCO
