air and pollution课件

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1、组员：姜智超李杰鸿余璐静史宇AirandPollutionTheImportanceofAirAirisamixtureofgasesItisimportant:forlife;containsoxygenwhichsupportslife,waterandcarbondioxidewhichgreenplantsneedtomakefoodfortheprotectionfromultravioletradiationofthesun(ozonelayerintheupperatmosphere)fortheb

2、urningoffuelsfortheproductionofheatenergyinpowerstationsasasourceofnitrogen,oxygenandargon(noblegas)CompositionofAirNitrogen78%Oxygen21%Carbondioxide0.03%Argonandraregases1%WatervapourVariable(0–5%)argon(1%)oxygen(21%)nitrogen(78%)AirPollutionPollutantsa

3、resubstancesthatmayharmlivingthingsordamagenon-livingthings.Somecommonatmosphericpollutantsare:carbonmonoxidemethanenitrogenoxides(NOandNO2)ozonesulfurdioxideunburnedhydrocarbonsCarbonmonoxideColourlessandodourlessgasComesfromtheincompletecombustionoffuelinve

4、hicles;allnewmotorcarsinSingaporearefittedwithcatalyticconverters;oxidisesCOtoCO2Canbeabsorbedbyhaemoglobinintheblood,thusbloodcannolongerabsorbO2ExtraamountsofCOresultintiredness,headaches,heartdamageandsmallamountscanbelethalMethaneSmallamountsofmethanearen

5、aturallypresentintheatmosphere;bacterialdecayofvegetationandothersourcesIncreasingamountofmethaneinrecentyearsobserved;humanactivitiessuchasagriculture,miningandwastedisposalMethane(heat-trappinggas)causes‘greenhouseeffect’/globalwarmingRicefieldsareamajorsou

6、rceofmethaneOxidesofNitrogenOxidesofnitrogen(NOandNO2)areproducednaturallyinlightningandforestfiresExcessman-madeproductionofoxidesofnitrogenisharmful;foundinsidemotorcarengines,powerstationsandindustriesDamagepeople’slungsandreactwithotherpollutantstoformozo

7、nePreventivemeasure:motorcarsarefittedwithcatalyticconverterstoreduceoxidesofnitrogentoN2OzoneOzone,O3,atgroundlevelisanastypollutantIrritatespeople’seyes,chestsandthroatsandcausesbreathingdifficultiesProducedbytheactionofsunlightonpollutantssuchasNO2andhydro

8、carbons;formationofa‘photochemicalsmog’Preventivemeasure:reducetheemissionsofunburnthydrocarbonfuelsSulfurdioxideFuels(coalandpetroleum)containsulfurasanimpurity;whenfuelsareburnt,sulfuri