about air pollutionDOC.docx

about air pollutionDOC.docx

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aboutairpollutionDOC

July31（Reuters）-BeijinghaspromisedcleanairfortheOlympicGamesithostsinAugust,butexpertssaythewaytheChinesecapitalmeasuresitspollutionmeansthateven"blueskydays"maynotbeentirelysafeforathletes.

Belowfinddetailsofmajorproblemswithitsairqualitystandards,andhowitssafetylevelsmatchuptointernationalguidelinesandthoseofothermajorpolluters.

THEAIRPOLLUTIONINDEX

ThisisBeijing'sgeneralguidelinetowhetherthecity'sairissafetobreathe,andisusedtomeasureifthecapitalhasmetits"blueskies"targetforthenumberofdayswithsafeair.Butscientistssayithasseveralkeyflaws.

--Itomitsatleasttwodangerouspollutants,ozoneandfineparticulatematter.

--Theoverallvalueiscalculatedbytakinganaverageofreadingsacrossthecity,meaningsomeareascouldhavedangerouslevelsevenon"bluesky"days.

--Theindexdoesnottakeintoaccountthecumulativeeffectofdifferentpollutants,measuringonlywhetherlevelsofeachiswithinitsownguidelines.

AIRSTANDARDS

China'sairqualitystandardsarenotastightasmostU.N.uidelines,butarestricterthanmanyoftheU.S.rules.

Theydonothowevercoverparticulatematter2.5,fineparticlesthatscientistssaydamagethelungsandmayalsobeabletoseepintothebloodstream.

Thecountryhasseparatelimitsfordifferenttypesofarea.ClassIisprotectedareas,andClassIIisforresidentialareasandClassIIIisindustrialareas,wherethegovernmentallowsdirtierairbecausepeoplespendlesstimethere.

2.Citiessettojointlyfightairpollution

Ensuringcleanairwillnolongerbethetaskofasinglecity-itwillbetheresponsibilityofaclusterofcitieswhosepollutantsaffecteachother,accordingtoaplanbeingfinalizedbythegovernment.

Theeconomicandindustrialhubs-theYangtzeRiverDelta,thePearlRiverDelta,andtheBeijing-Tianjin-Hebeiregion-willbethepioneersexecutingtheplan,EnvironmentalProtectionMinisterZhouShengxiansaidwhilepresentingareportoncontrollingairpollutiontothetoplegislatureyesterday.

Theplanislikelytoincluderegionalemissioncaps,ZhangLijun,vice-ministerofenvironment,toldreporters.

Hesaidtheplans,whicharebeingdrafted,areexpectedtotakeeffectfromthebeginningofthe12thFiveYearPlan（2011-15）.

Zhousaidthethreeregionswilltaketheleadbecause"theyseeconcentratedairpollutantemissions,andsufferheavyairpollution".

Accordingtoministryfigures,thethreeregionsoccupyonly6.3percentofthecountry'sareabutconsume40percentofthecountry'scoalandproducehalfofitssteel.Theyarealsohometoatleast200millionpeople.

"However,becauseairpollutantsaretransient,thecurrentplansofindividualcitiesdonotsolvetheproblem,"Zhousaid.

AreportfromtheNationalPeople'Congress'EnvironmentalandResourcesProtectionCommitteereleasedyesterdayshowsabout30percentofairpollutantsinBeijingarefromotherplaces.

Italsosaysacidrain,ozoneandsmallparticlesoccurmoredenselyinthesecitygroupsthanotherpartsofthecountry.

TheYangtzeRiverDeltaandtheBeijing-Tianjin-Hebeiregionseeheavyphotochemicalpresence,asevereanddangerouspollutioncreatedasnitrogenoxidesandhydrocarbonsreacttosunlight.

AndthePearlRiverDeltaissufferingrisingdusthazepollution,accordingtothereport.Itsaystheregionsawmorethan100daysofhazelastyear.

"Giventhesituation,airpollutioncontrolsbasedonasinglecityarecostlyandineffective,"PuHaiqing,vice-chairmanofthecommittee,said."It'simperativeforcitiestojoinhands."

Zhangsaidthesuccessfulregionalairpollutioncontrolmeasuresadoptedduringlastyear'sOlympicGameswillbevaluableexperienceforplanning.

BeijingandneighboringmunicipalityTianjinaswellasHebei,InnerMongolia,ShanxiandShandongcutemissionstoensurecleanairfortheGames.Theplanalsocoveredthecontrolofdust,automobileandindustrialemissions,andcoalconsumption.

ButZhangJianyu,ChinaprogramheadoftheUS-basedEnvironmentalDefenseFund,saidtemporarymeasurestakenduringtheGames,suchastrafficcontrolsinTianjin,couldnotbelong-termsolutions.

"Regionalplansareobviouslyastepforward,"hesaid."Buttoensureimplementation,administrativemeasuresalonecannotwork."

Zhangsaidbalancingtheinterestsofdifferentcitiescouldbehard,sotheymustbeaccompaniedbyeconomicincentivesorevenlegislation.

Meanwhile,atleasttwoindices-ozoneandparticleslessthan2.5microns（PM2.5）-willbepartoftheairqualityevaluationsystemtoofferpeopleaclearerpictureofairquality.

Thecurrentevaluationsystemincludesonlythreeindices:

Sulfurdioxide,carbondioxideandparticleslessthan10microns（PM10）,buttheydonotreflecttrueairquality,theenvironmentministersaid. 

3.Earlyconcernsregardingthehealth-relatedeffectsofairpollutionoriginatedfromsevereepisodesinMeuseValley,Belgium,in1930;Donora,Pennsylvania,in1948;andLondon,in1952.Althoughtheoveralleffectsoftheseepisodescontinuetobedebated,well-documented,episode-relatedincreasesinmorbidityandmortalityfromcardiopulmonarycausesprovideddramaticevidencethatextremelyhighconcentrationsofairpollutioncanhaveseriousadverseeffectsonhealth.Earlypublic-policyeffortstoimproveairqualityintheUnitedStates,Britain,andelsewherewerelargelyattemptstoavertsuch"killer"episodesofairpollution.IntheUnitedStates,aseriesofnationallegislativeandregulatoryeffortstocontrolairpollutionwereinitiated

    Fromthe1960sthroughthe1980s,afewscatteredstudiescontinuedtosuggestthatairpollutionhadadverseeffectsonhealth.1,2Then,duringtherelativelyshortperiodof1989through1995,severallooselyconnectedepidemiologicstudiesreportedadverseeffectsofunexpectedlylowlevelsofparticulate-matterairpollution.3,4,5,6Althoughhighlycontroversial,7theseresultspromptedseriousreconsiderationoftheparticulate-matterstandardsandhealthguidelines（Figure1）.Theyalsopromptedextensiveeffortstoreanalyzekeystudies8（whichwerelargelyconfirmatory）andmotivatedrapidgrowthinepidemiologic,toxicologic,andotherstudiesoffineparticulatematterandothercombustion-relatedairpollutants.

    Researchhascontinuedtosuggestthatalevelofairpollutionthatiscommoninmanyurbanandindustrialenvironmentsisanimportantriskfactorforvariousadversehealtheffectsinhumans.Althoughmanysuchstudieshavefocusedonrespiratorydisease,substantialandgrowingevidenceindicatesthatfineparticulateairpollutionisalsoariskfactorforcardiovasculardisease.9,10Short-termexposureexacerbatesexistingpulmonaryandcardiovasculardiseaseandincreasestheriskofsymptoms,theneedformedicalattention,anddeath.1Long-term,repeatedexposureincreasesthecumulativeriskofchronicpulmonaryandcardiovasculardiseaseanddeath.9,10,11,12,13

    Onenotableresearcheffortthatbeganintheearly1990sinthemidstofthecontroversiesaboutairqualitywastheChildren'sHealthStudy.Thisstudyprospectivelymonitoredthelungfunctionofschoolchildrenfromtheagesof10to18yearsin12southernCaliforniacommunitieswitharelativelywiderangeofairpollutants.AsreportedbyGaudermanetal.inthisissueoftheJournal,14airpollutionwassignificantlyassociatedwithdeficitsinlungdevelopment.Withinthecontextoftheoverallliteratureonairpollutionandhumanhealth,thisarticlemakesseveralimportantandconfirmatorycontributions.

    TheChildren'sHealthStudyevaluatedthecumulativeexposuretovariouspollutantsoveraneight-yearperiod.Deficitsinthegrowthoflungfunctionovertheeight-yearperiodwereassociatedwithacorrelatedsetofpollutantsthatincludedfineparticulatematterwithanaerodynamicdiameteroflessthan2.5μm,nitrogendioxide,acidvapor,andelementalcarbon.Theseresultsareconsistentwiththoseofpreviousepidemiologicstudiesthathaveimplicatedfineparticulatematterandassociatedcombustion-relatedairpollutantsasbeinglargelyresponsiblefortheobservedhealtheffectsofairpollution.1,2,5,11,12,13Variousphysiologicalandtoxicologicfindingssuggestthatexposuretofineparticulatemattermaybeanimportantpublichealthconcern.Suchmatter,whichcanbebreatheddeeplyintothelungs,includessulfates,nitrates,acids,metals,andcarbonparticleswithvariouschemicalsadsorbedontotheirsurfaces.Furthermore,fineparticulatematterisubiquitousbecauseitislargelyderivedfromcommoncombustionprocesses（suchasenginesinmotorvehicles,manufacturing,powergeneration,andburningofbiomass）andbecauseitistransportedoverlongdistancesandreadilypenetratesindoors.

    Understandingtheshapeoftheexposure–responserelationshipanddeterminingwhethertherearesafethresholdsareimportantfortheformulationofpublichealthpoliciesforpollutioncontrol.Mortalitystudiessuggestthattheexposure–responserelationshipsforparticulate-matterpollutioninthecaseofbothshort-term15andlong-term11exposuresarenearlylinear,withnodiscerniblesafethresholdswithinrelevantrangesofexposure.Likewise,intheChildren'sHealthStudy,theexposure–responserelationshipsappeartobenearlylinear,withoutdiscerniblesafethresholds.

    Anissuewithclinicalimplicationsconcernstheidentificationofgroupsthataremostatriskorthataremostsusceptibletotheeffectsofpollution.Oneevaluationoftheliterature1suggeststhattheproportionofagivenpopulationthatisatriskfordeath,hospitalization,or