文章Cars，pollution and health.doc

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1、Cars,AirPollutionandHealthCarshavetwooppositepersonalities.Oneisfriendlyandattractivetheotherisdestructiveandcanbelethal.Thedesiretoownacarislinkedtopleasure,sexuality,convenienceandfreedom.Menlustforattractive,prestigiouscarstheywaytheylustforwomenandwomendes

2、iremenwithattractive,prestigiouscars. Carmanufacturershavelongusedattractive,lightlycladwomentoadvertisetheirlatestautodesigns.Menarealsointerestedinpower,performanceandwanttoknowsomethingabouttheengine,althoughmodernenginesaresufficientlycomplextodiscourageev

3、entheprofessionalmechanic.Someofthenewenginecomplexityinvolvesemissioncontrolsystemsthatrequireelectronicmonitoringandadjustmentofengineperformanceunderdifferentoperatingconditions.Severaldevicesareaddedtotheenginetohandleairflowin,fueldeliveryandexhaustout.Co

4、mputershavebeenaddedtomonitorandcontrolengineperformance.Mostcarenginesdesignedafter1996haveastandardportthatallowsadiagnosticcomputeraccesstoinformationaboutengineperformance.Drivingacaristhemostpollutingactanaveragecitizencommits.Emissionsfrompassengervehicl

5、esareincreasinginCanadaandtheUSdespiteattemptstomakeenginesmorefuelefficientanddespitetheadditionofantipollutiondevices.Themainreasonisthatcarsaregettingbiggerandpick-uptrucks,vansandsportsvehiclesareoftenreplacingsmaller,lighterpassengercars.Theaveragenewvehi

6、clein2003consumedmorefuelthatitscounterpartin1988.IntheUSAin1987carsaveraged25.9milestothegallon.Fuelefficiencydroppedto24.6miles/gallonby1998andisdroppingfurtheraslargervehiclesreplacesmallerones.Despitescientificevidence,governmentsinmostaffluentcountrieshav

7、eignoredtheirresponsibilitytoreduceemissionsofgreenhousegases.TheUSAisbiggestemitterofgreenhousegasesworldwide.USemissionshaveincreasedto7billiontonesofCO2in2004,16%higherthanemissionsinthelate90's.TheUKhasdonebetterreducingtheiremissionstoabout0.6billiontons,

8、14%below 1990levels.Exhaustfromallcombustionenginescombinetoproducelocaladverseeffectsonthehealthofcarusersandallinnocentbystanders.Citieshavebecomeislandsoftoxicchemicalsfromtheun