PM2英语作文.docx
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PM2英语作文.docx
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PM2英语作文
PM2.5
PM2.5particles-fineparticlesinthe(ambient)air2.5micrometersorlessinsize(knownasPM2.5).These"PM2.5particles"areknowntoproducerespiratoryandcardiovascularillness.Shortfor"ParticulateMatter,2.5micrometersorless""PM2.5particlesareairpollutantswithadiameterof2.5micrometersorless,smallenoughtoinvadeeventhesmallestairways.Theseparticlesgenerallycomefromactivitiesthatburnfossilfuels,suchastraffic,smelting,andmetalprocessing.PM2.5particlesweremeasuredinmicrogramspercubicmeter.
Forevery10microgramspercubicmeterincreaseofPM2.5,CIMTincreasedby5.9percent.Afteradjustingforvariousfactors,includingsmoking,theresearchersfoundthatCIMTincreasedby3.9to4.3percentforevery10microgramspercubicmeterincreaseinPM2.5.Thereweregreaterincreasesinpeopleover60,women,andpeopletakingcholesterol-loweringmedication.Thegreatestincreaseswereseeninwomen60orolder:
a15.7percentriseinCIMTforevery10microgramspercubicmeter.Thechangesobservedweresimilartothosethatoccurinpeoplelivingwithsmokers,Kuenzlisaid.
AccordingtoKuenzli,airpollutioncancauseinflammatoryresponsesbothinthebody'srespiratorytractandinthebloodvessels.Inthecaseofthecirculatorysystem,thiscaneventuallyleadtothickeningofthearterywallanditsattendantproblems.
Rabbitstudieshadshownthatexposuretoairborneparticlesproducedallthesignsofatherosclerosis,whilehumanstudieshaveshownthatinhalingtheseparticlesresultedinsystemicinflammation."Wethinkit'splausible,"Kuenzlisaid."
ChinaGoestoWaronPM2.5
Bigcitiesaretoldtobeginusingastricterstandardtomeasureairquality,butexpertswonderwhetherthishascometoolate.
BystaffreportersGongJingandCuiZheng
In2011,publiccallsforthegovernmenttouseamorestringentairqualitystandardgrewlouder.
Ultimately,thegovernmentwasswayed,anditincludedPM2.5–smallparticulatematterof2.5micronsindiameterorlessthatareeasilyabsorbedintothelungs–inthelatestNationalAmbient.
AirQualityStandards.EachprovincialcapitalandmunicipalitywillbeginmonitoringPM2.5in2012.
However,thenewstandardrevealsagrimpictureofChina'sairquality.SeveralscholarspointoutthatifChina'scitiespublishPM2.5datanow,80percentwouldnotmeeturbanairqualitystandards.
ABeijingmunicipalgovernmentplanannouncedinFebruaryhasthecapitalreachingthenationalstandardofannualaveragePM2.5concentrationsof35microgramspercubicmeterby2030attheearliest.ThismeansBeijingresidentswillneedtowaitatleast18yearstobreathairthatmeetsnationalstandards.Meanwhile,theplanprovidesthatBeijing'sPM2.5concentrationwillreach60microgramspercubicmeterby2015and50microgramspercubicmeterby2020.China'senvironmentalofficialsdonotsaywhataPM2.5concentrationof35microgramspercubicmetermeansorwhatriskitposestopeople'shealth.However,theU.S.EnvironmentalProtectionAgency'sAirQualityIndex,whichusesPM2.5asitsstandard,saysareadingof0-50means"good"airquality.
DuShaozhong,whorecentlyretiredasdeputydirectoroftheBeijingEnvironmentalProtectionBureau,saidthecityneededamiracletomeettheairqualitystandardin18years.Beijinghasalreadytakenextraordinarymeasurestoimproveairqualityoverthepastdecade,hesays,andfurtherimprovementwillbeevenmoredifficult.
FengYinchang,apollutionexpertatNankaiUniversityinTianjin,saidairpollutionhasactuallyimprovedinrecentyears."ThisisnottheworstperiodinhistoryforairqualityinChina'scities,"hesaid.Basedonhiscalculations,theworstperiodwastheyears1998to2000.
TherearefourmillionmoremotorvehiclesinBeijingnowthanin1998,andexhaustpollutionhasgrowntentimes.Sincethen,Beijing'sareahasgrownanditspopulationhasincreasedfromsome12millionpeopletomorethan20million."Existingpollutionsourceshavebeentreated,butnewpollutionsourceshavebeenaddedincrementally,"Fengsaid.
Overthepastdecade,Beijinghasemployedmorethan200measurestocontrolairpollution,Dusaid.Theeffectivenessofthesestepshasbeensignificant,but,helaments,duringthisperiod"Beijing'sairhasnevermetstandards."
Expertsdivideairpollutionintothreecategories:
simplesmokepollution;smokepollutionplusdust,knownasmixedpollution;andmixedpollutionplusvehicleexhaust,knownascompoundpollution.InChina,thesethreecategoriescoexist.Beijing'splanintroducedeightmeasures,includingstepsaddressingmonitoring,transportation,coal,dustandindustry.
Regardingtransportation,thecategorythatmostconcernsthepublic,thecityproposedphasingoutoldcarsaheadofapreviousscheduleandexpandingpublictransportationby2015.Alsobythatyear,morethanathousandasphalt,glassandotherfactorieswillleavethecity,andamajorchemicalplantwillbeclosed.By2020,allthecity'scementplantswillbeshuttered.Beijingalsoplanstoreduceannualcoalusefrommorethan26milliontonstolessthan10milliontonsby2020.
Regardingdust,Beijinghasproposedstrictcontrolofdirtyconstructionprojects,roadsweepingandtruckscarryingslag.
Whenthecitysuffersheavyhazeinthefuture,Beijingsaysitwillimplementamorecomprehensiveemergencyplan,suspendingconstructionsiteearthworkoperationsandsedimenttransport,andstoppingorreducingsomeproduction.Municipal-levelpartyandgovernmentofficesandinstitutionsaretoceaseusingsomevehicles.
Thecapitalalsoplanstoadd667hectaresofforestoverthenextfiveyears.Fengpraisedthemeasuresasstrong,butofficialshavenotedthatsucheffortswillonlyreducePM2.5by15percentby2015,evidenceofthedifficultyreducingpollution.Asforcompoundpollution,themostdifficultcategorytocontrol,scholarssaytheproblemissolargethatChinaneedsan"exhaustrevolution."InBeijing,forexample,datafromthecity'senvironmentalprotectionauthorityshowsthatmotorvehicleexhaustisresponsibleformorethanone-fifthofPM2.5pollution.
ProfessorZhuTong,ofPekingUniversity'sCollegeofEnvironmentalScienceandEngineering,saidChinashouldhavestartedaddressingthePM2.5problemadecadeagoandthatthegrowingnumberofmotorvehiclesisexacerbatingthesituation.
OfficialfiguresshowthatBeijing'sairqualityisworsethanShanghai's.OnereasonforthisisthatShanghaihassomethreemillionvehicles,whilethecapitalhasmorethanfivemillion.
ScholarspointoutthatChinaNationalPetroleumCorporation,Sinopecandotherstate-ownedoilrefineriesthatenjoymonopolieshaverefusedtoupgradethequalityofpetroleumproducts.Theydothistoprotecttheirinterests,anditmeansthatvehicleexhaustisevendirtierthaninothercountries.
Inaddition,thelayoutofmostChinesecitiesmakestheexhaustproblemworse.Poorroadplanningmeanstrafficcongestionandmorepollutionfromvehicles.Fengsaidthattomanagemotorvehiclesproperly,citiesfirstmustimprovetheirlayoutsocarownerscouldliveclosertoworkanddriveless.Ultimately,China'seconomicgrowthmodelmustundergoarevolutionarychange,Fengsaid.High-pollutingcompaniesmustbeclosedandotherindustriesmustimproveenvironmentalcontrols.Dependenceoncoalmustbereduced.
Indeed,theproblemisanationalone.Airpollutionnaturallymoveswithaircurrents,meaningcitiesshareeachother'sfoulair.InBeijing,forexample,one-quarterofPM2.5comesfromneighboringregions.TheMinistryofEnvironmentalProtectionisencouragingregionsliketheBeijing-Tianjin-Hebeiarea,theYangtzeRiverDeltaandthePearlRiverDeltatounitetocombatpollution.
Manyprovincesandmunicipalitieshaverespondedactively,butnoareaotherthanBeijinghasputforwardspecificmeasures,norhavetheysaidhowmuchfundingwillgotowardenvironmentalmanagement.
TheconsensusamongscholarsisthatiflocalgovernmentsarenotwillingtolosingaportionofGDPtoprotecttheenvironment,theendresultismostlikelytreatmentthatdoesnotkeeppacewithpollution,andtheracebetweentreatmentandpollutionwillbelost.
Feng'sprescriptionforcontrollingurbanPM2.5isforlocalgovernmentsfirsttohireresearcherstoclarifythesourcesofpollutionintheircitiesandthewaysthatpollutionsourceschangeatdifferenttimes,thenworktodevelopsolutions.Thethreedifferentcategoriesofairpollutionwillrequireuniqueapproachestobecleanedup,hesays.
CanChinawinitswaronairpollution,andifso,howlongwillittake?
Recentstepstakenbythegovernmentgivereasonforoptimism,butthecritiquesbyscholarssuchasFengsuggestthattheroadtocleanerairwillbealong,dirtyone.
BeijingReleasesPM2.5AirQualityReadings
Aftermonthsofcontroversyandpublicoutcryoverthickpollutioninthecapital,BeijingofficialshavestartedtopublishairqualityreadingsforsmallparticulatesCompiledbyCaixin
BeijingmunicipalofficialsforthefirsttimereleasedtheirairqualityreadingsonJanuary21,followingmonthsofpublicoutcryoverheavyhazethatsometimesblanketedthenation'scapitalandshutdownairflights.
TheBeijingMunicipalEnvironmentalMonitoringCenteronJanuary21announcedthatithassetupanewmonitoringstationfortracking"PM2.5,"orparticularmatterunder2.5micronsindiameter,atitsChegongzhuangsite.Thecenterispublishingthereadingsonitswebsitehttp:
//.
Formonths,thephrase"PM2.5"hasbeenahottopiconforumsandmicroblogs,afterthicksmogdescendedonthenation'scapita
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