酸雨(Acid-rain)

AcidRain酸雨OverviewDefinitionCausesProcessImpactsSolutionsDefinitionofAcidRainPrecipitation(rain)thathasapHoflessthanthatofnaturalrainwater(whichisabout5.6duetodissolvedcarbondioxide).Itisformedwhensulphurdioxidesandnitrogenoxides,asgasesorfineparticlesintheatmosphere(大气层）combinewithwatervapourandprecipitateassulphuricacidornitricacidinrain,snow,orfog.CausesofAcidRainNaturalSourcesEmissionsfromvolcanoesandfrombiologicalprocessesthatoccurontheland,inwetlands,andintheoceanscontributeacid-producinggasestotheatmosphereEffectsofacidicdepositshavebeendetectedinglacialicethousandsofyearsoldinremotepartsoftheglobeCausesofAcidRain•DuetoMan•Burningcoal煤.Oilandnaturalgasinpowerstationsmakeselectricity,givingoffsulphurdioxidegas.Burningpetrolandoilinvehicleenginesgivesoffnitrogenoxidesasgases.Thesegasesmixwithwatervapourandrainwaterintheatmosphereproducingweaksolutionsofsulphuricandnitricacids–whichfallasacidrain.FormationofAcidRainWhenwatervapourcondenses,orastherainfalls,theydissolve(溶解)inthewatertoformsulphuricacid(H2SO4)andnitricacid(HNO3).Whiletheairincleanedofthepollutantsinthisway,italsocausesprecipitationtobecomeacidic,formingacidrainTheProblem!Peopleprobablycouldn'tlivewithoutelectricity!Thereforecoalwillcontinuetobeburnt.Also,electricityandenergyareconstantlybeingoverused.Thinkofitthisway:everytimeyouturnonalightswitchorthetelevisionsetwithoutreallyneedingto,you'reindirectlycontributingtotheacidrainproblem.Moreproblems!!!Acidraincantravellongdistances.Oftenitdoesn’tfallwherethegasisproduced.Highchimneys(烟囱)disperse(spread)thegasesandwindsblowthemgreatdistancesbeforetheydissolveandfalltoEarthasrain.E.g.gasesproducedinEnglandandWesternEuropecanresultinacidraininScotlandandScandinavia.HowAcidRainAffectsTheEnvironment?Acidrainisanextremelydestructiveformofpollution,andtheenvironmentsuffersfromitseffects.Forests,trees,lakes,animals,andplantssufferfromacidrain.TreesTheneedlesandleavesofthetreesturnbrownandfalloff.Treescanalsosufferfromstuntedgrowth;andhavedamagedbarkandleaves,whichmakesthemvulnerabletoweather,disease,andinsects.ForestsaffectedbyAcidRainNortheastUSCanadaNorthernEuropeAsiaAllofthishappenspartlybecauseofdirectcontactbetweentreesandacidrain,butitalsohappenswhentreesabsorb(吸收)soilthathascomeintocontactwithacidrain.Thesoilpoisonsthetreewithtoxic(有毒的)substancesthattherainhasdepositedintoit.AcidNeutralizationHowdoesthiswork?CationExchangeonclaymineralsRoleofchemicalweathering...AcidRainandTreesLakesarealsodamagedbyacidrain.Fishdieoff,andthatremovesthemainsourceoffoodforbirds.Acidraincanevenkillfishbeforetheyarebornwhentheeggsarelaidandcomeintocontactwiththeacid.Fishusuallydieonlywhentheacidlevelofalakeishigh;whentheacidlevelislower,theycanbecomesick,sufferstuntedgrowth,orlosetheirabilitytoreproduce.Also,birdscandiefromeatingtoxicfishandinsects.BuildingsAcidraindissolvesthestoneworkandmortarofbuildings(especiallythosemadeoutofsandstoneorlimestone).Itreactswiththemineralsinthestonetoformapowderysubstancethatcanbewashedawaybyrain.AcidRainandBuildingsManybuildingsaremadeofconcreteandorstoneThesecompoundsactasbases(alkaline)andreactwithacidThebuildingtechnically“weathers”veryfast,orNontechnically“crumbles”TransportCurrently,boththerailwayindustryandtheaeroplaneindustryarehavingtospendalotofmoneytorepairthecorrosive(腐蚀性的)damagedonebyacidrain.Also,bridgeshavecollapsed(倒坍)inthepastduetoacidraincorrosion.HumansHumanscanbecomeseriouslyill,andcanevendiefromtheeffectsofacidrain.Oneofthemajorproblemsthatacidraincancauseinahumanbeingisrespiratory(呼吸的)problems.Manycanfinditdifficulttobreathe,especiallypeoplewhohaveasthma.Asthma,alongwithdrycoughs,headaches,andthroatirritationscanbecausedbythesulphurdioxidesandnitrogenoxidesfromacidrain.Braindamage,kidneyproblems,andAlzheimer'sdiseasehasbeenlinkedtopeopleeatingtoxicanimals/plants.Acidraincanbeabsorbedbybothplants(throughsoiland/ordirectcontact)andanimals(fromthingstheyeatand/ordirectcontact).Whenhumanseattheseplantsoranimals,thetoxinsinsideoftheirmealscanaffectthem.Braindamage,kidneyproblems,andAlzheimer'sdiseasehasbeenlinkedtopeopleeatingtoxicanimals/plants.ResearchcarriedoutinNorthAmericain1982,revealedthatsulphurpollutionkilled51,000peopleandabout200,000peoplebecomeillasaresultofthepollution.AffectedAreasIndustrialacidrainisasubstantialprobleminChina,EasternEuropeandRussiaandareasdown-windfromthem.AcidrainfrompowerplantsintheMidwestUnitedStateshasalsoharmedtheforestsofupstateNewYorkandNewEngland.Thisshowsthattheeffectsofacidraincanspreadoveralargearea,farfromthesourceofthepollutionWheredoNemissionsoriginate?~55%comefromagriculture~25%comefromindustry–e.g.coalfiredpowerplants~20%comefromautomobilesWhatarethesolutionstoacidrain?SolutionsSulphurdioxidecanberemovedfrompowerstationschimneysbutthisprocessisexpensive.Reducetheamountofelectricityweuseturntv’soffatthemains,don’tleaveonstandby.-turnofflightswhenaroomisnotinuse.Userenewableenergylikewindpower,solarpanels,tidalpower,andgeothermal(地热的)energy.SolutionsFitcatalyticconverterstovehicleexhaust