Chapter2:LivingEnvironmentalandHealth

Section1.AtmosphericPollution

一.Characteristicsoftheair

二.Healtheffectsofatmosphericpollutiononhumanbody三.Healtheffectsofprincipalairpollutants四.Protectivemeasureofairpollution一Characteristicsoftheair

(一)Earth'sAtmosphereTheEarthissurroundedbyablanketofair,whichwecalltheatmosphere.Itreachesover2000~3000kilometersfromthesurfaceoftheEarth,soweareonlyabletoseewhatoccursfairlyclosetotheground.

LifeonEarthissupportedbytheatmosphere,solarenergyandourplanet'smagneticfields.TheatmosphereabsorbstheenergyfromtheSun,recycleswaterandotherchemicals,andworkswiththeelectricalandmagneticforcestoprovideamoderateclimate.Theatmospherealsoprotectsusfromhigh-energyradiationandthefrigidvacuumofspace.4地球大氣層灰塵、霧、水汽等能吸收14％太陽輻射43％到達地表43％折回宇宙空間

TheenvelopeofgassurroundingtheEarthchangesfromthegroundup.Fivedistinctlayershavebeenidentifiedusingthermalcharacteristics(temperaturechanges),chemicalcomposition,movement,anddensity.1).TroposphereThetropospherestartsattheEarth'ssurfaceandextends8to14.5kilometershigh.Thispartoftheatmosphereisthedensest.Asyouclimbhigherinthislayer,thetemperaturedropsfromabout17to-52degreesCelsius.Almostallweatherisinthisregion.Thetropopauseseparatesthetropospherefromthenextlayer.Thetropopauseandthetroposphereareknownastheloweratmosphere.2).Stratosphere

Thestratospherestartsjustabovethetroposphereandextendsto50kilometershigh.Comparedtothetroposphere,thispartoftheatmosphereisdryandlessdense.Theozonelayer,whichabsorbsandscattersthesolarultravioletradiation,isinthislayer.Ninety-ninepercentof"air"islocatedinthetroposphereandstratosphere.Thestratopauseseparatesthestratospherefromthenextlayer.3).Mesosphere

Themesospherestartsjustabovethestratosphereandextendsto85kilometershigh.Inthisregion,thetemperaturesagainfallaslowas-93degreesCelsiusasyouincreaseinaltitude.Thechemicalsareinanexcitedstate,astheyabsorbenergyfromtheSun.Themesopauseseparatesthemesospherefromthethermosphere.Theregionsofthestratosphereandthemesosphere,alongwiththestratopauseandmesopause,arecalledthemiddleatmospherebyscientists.ThisareahasbeencloselystudiedontheATLASSpacelabmissionseries.4).ThermosphereThethermospherestartsjustabovethemesosphereandextendsto600kilometershigh.ThetemperaturesgoupasyouincreaseinaltitudeduetotheSun'senergy.Temperaturesinthisregioncangoashighas1,727degreesCelsius.ChemicalreactionsoccurmuchfasterherethanonthesurfaceoftheEarth.5).ExosphereTheexosphereistheoutermostlayeroftheEarth'satmosphere.Theexospheregoesfromabout640kilometershightoabout1,280kilometers.Thelowerboundaryoftheexosphereiscalledthecriticallevelofescape,whereatmosphericpressureisverylow(thegasatomsareverywidelyspaced)andthetemperatureisverylow.Inthisregionoftheatmosphere,HydrogenandHeliumaretheprimecomponentsandareonlypresentatextremelylowdensities.（二）Chemicalcompositionandphysicalpropertiesoftheatmosphere1.ChemicalcompositionoftheAtmosphereTheatmosphereisprimarilycomposedof20.95%ofoxygen(O2),78.09%ofnitrogen(N2),smallpartofargon(Ar)andraregas.Thecomponentofairisratherconstant,butowingtohumanactivities,alargenumberofimpuritiesarecarriedintotheair.2.Physicalpropertiesofair1)Solarradiation2)Meteorologicalfactor3)Airionization1.Solarradiation波長γ-射線X-射線紫外線可見光紅外線微波無線電波組成太陽光譜1)Solarradiation(1)UltravioletRadiation(UVR)

UVRisbiologicallymostactivepartofthesunlight.Itcanbedividedintothreeparts.UV-Awithwavelengthof320~400nm,itisalsocalledlongwaveUVR,UV-B275~320nmmiddlewaveandUV-C200~275nmshortwave.①UV-A:pigmentationeffectUV-Aiscapableofconvertmelanogentomelaninviaoxygenasepathwayanddepositsitinepidermis.Theprocessiscalledpigmentation,ortanning.

MelaninpigmentcanpreventUVfrompenetratingdeeper,causedamagetodermisthereforeappearstobeadefensivemechanismoftheskin.UV-Acanalsoincreasetheimmunefunctionofthewholebody,increasemetabolismoftissue.Itseffectisadvantageoustohumanhealth.②.UV-B

erythemaeffect

anti-rachiticeffect

immuneregulatoryfunctionUV-BpossessesthreeeffectsonhumanbodyandthestrongestbiologicalactionamongUVR.

FirstbiologicalactionofUV-Bistheerythemaleffect.UV-Biscapableofproduceerythemaonexposedareaoftheskin,whichisthereleaseofbiologicallyactivesubstance,suchasprostaglandin2,histaminefromkeratocyteorendothelialcellofthebloodvessels,causedilationofbloodcapillaries,increaseitspermeabilityandinfiltration,leadtoedemaandrush.

ThebiologicaldoseofUV-Bcanbemeasuredbytheunitofminimalerythemaldose(MED),whichisthelowestdoseofUV-Brequiredforinductionavisibleerythema.

SecondfunctionofUV-B

isanti-rachiticeffect.ExposureofUV-Bcanconvertergosteroland7-dehydrocholesterolintocalciferol(VD2)andcholecalciferol(VD3),VitaminDiscapablepromotetheabsorptionofcalciumingastrointestinaltractandtheformationofbone.100unitofVDisneededformaintainnormalCaandPmetabolism.Butonly1/4canbeobtainedfromthedietinChinesepopulation.Therestshouldbeobtainedbysunlightexposure.Inadditioninnorthernpartofourcountryowingtohighdegreeoflatitude,sunlightcontainslittleUV-Binwinterseasonthereforericketsisprevalentandconstituteoneofthemostpopulardiseasesinchildrenandosteomalacia(骨軟化)aremorefrequentlyfoundinelderlyperson.

ThirdbiologicaleffectofUV-Bisimmuneregulatoryfunction.UV-Bpossessestheregulatoryeffectonimmunity.ItisdemonstratedthatUV-Bhasthefunctionofimmuneregulation.ProperdoseofUV-Bincreasesbothcellularandhumoralimmunity.③UV-C:germicidaleffect

UV-CistheshortwavelengthUVR,existingonlyinartificiallight.Solarspectrumongroundsurfacestartswith290nm,andthewavelengthshorterthan290nmisfilteredoutwhenitpassatmosphericlayer.

UV-Cisgermicidallight,whichcandamagingDNA,causedegenerationofnuclearprotein,thenkillbacteria.Afterpassingwindowglass,noshort-waveUVRpresentinsunlightbutisstillcapableofinhibitionviabilityofpathogenicbacteria,thereforeisimportantforpreventionrespiratoryinfectiousdiseases.

Itistheresponsibilityofmedicalpersonnel,tocreatesunnyhealthyenvironment,persuadepeopletospendmoretimeoutdoorstogetmoresunshine.ItmustbeemphasizedthatexcessiveexposuretoUVRoverprolongedperiodisharmful.

ItisquiteclearthatexposuretoUVRisthemaincauseofskinaging.TheendpointofskinchangeexposedtoUVRisskincancer.Sincethediseaseoccurredinexposedareaofskin,andhasbeenprevalentinoutdoorworkers,andtheincidencerateisnegativelycorrelatedwiththelatitudewherethepeoplelive.Inaddition—eyeinjuries(cataract)—differentlatitudeanddifferentaltitude—differentextent.補充：反映紫外線輻射強度的指標稱紫外線指數（ultravioletindex,UVI）。紫外線指數從0至8級，該指數越高，對皮膚和眼睛的損害愈嚴重。紫外線指數可引起公眾對過量暴露紫外線輻射危險的關注和提醒人們戶外活動應采取哪些預防措施。紫外線指數達到3-4級時，戶外活動應用遮陽傘，穿戴寬邊帽和寬松服裝，涂抹防曬霜，配帶可過濾長波和中波紫外線的太陽鏡。(2)Infra-redrayInfraredhasawavelengthbetween760~3000nm.Itisahotradiation,widelyusedinphysiotherapy.Whenhumantissueabsorbsinfraredray,itstemperaturerises,causedilationofbloodvessel,enhancemetabolismandcellularproliferation,andacceleratewoundhealing.Therefor,itsantiphlogisticandanalgesiceffect（消炎鎮痛）isusedtotreatchronicskindiseases,nervouspainandfrostbite（凍傷）.Stronginfraredraycaninduceskinburn,sunstroke,whichisduetotheirradiationofinfraredrayontheheadofaperson,contributetotheriseinskintemperature.Theinfraredraycancausecataract,usuallyfoundinglassworkers,duetolongtermstairburninghotglassproduct,exposetheireyetotheray.(3)VisiblelightVisiblelighthasawavelengthof400~760nm.Itisthebaseforinductingvisualsense.Thevisiblelightthroughvisualorgangivesvisualsense,maintainexcitationofcentralnervoussystem.Thevisiblelightthroughdailycycleregulatesphysiologicalrhythm.2)Meteorologicalfactors

Weatherreferstosunshine,temperature,wind,rain,airpressure,overaparticularareaandataspecifictime.Climateisweatherconditionofaplaceorareawithreferencetoalongperiodoftime.Climatereferstothecombinationofairtemperature,airhumidity,aircurrent,airpressureandradiation.

Weatherandclimatehaveawidevariousinfluenceonhumanhealthespeciallyonpatients,whoareextremelysensitivetothechangeofweathercondition.Itmaybediscussedasfollows:(1).Thosediseasesofwhichitsetiologicagentarerelatedtotheweather,suchashayfever,bronchialasthma,etc.(2).Diseaserelatedtolife-stylethatisassociatedwithweather.Inwinterduetocoldweather,peopleareconfinedtothehouse.Denselyinhabited,closelycontacted,theygetlesssunshine,freshvegetableandseveralvitaminsindiet,andasaresultmanyinfectiousdiseasesoccurinwinterorearlyspring,includingrickets.(3).Coldandwetweathercontributestotheoccurrenceofrheumaticarthritis,heartdisease,myocarditis,acuteglomerularnephritis,andneuritis.Themechanismsarenotfullyunderstood,however,whenpeoplecatchcoldvasoconstrictionoccurnotonlylimitedtoskinbutalsoinremoteorgansuchaskidneyandtheseorgandeficientinbloodinfusion,thenreducetheirresistancetopathogenicgerm.(4).Coldweathercauseconstrictionofperipheralbloodvessel,elevatebloodpressure,increasemyocardialoxygendemandandheartburden,thereforemayaggravatetheconditionofcardiovasculardiseaseorevenleadtosuddendeath.3).AirionizationAirionsrefertoairmoleculeoratomwithunpairedelectron.Duetotheactionofcosmicray,UVR,orstorm,thunder,lightning,waterfallsorseawave,airmoleculelosselectroninoutmostlayerthenformpositiveairion,fallenofffreeelectronbindwithneutralatomormoleculeformnegativeion.Theprocessiscalledionization.Effectsofpositiveandnegativeions--oppositeAirionscanbeclassifiedaslightion,andheavyion.Lightioniscomposedofairionabsorbedbysomeneutralmolecule,whichislightinweightandlargeindiameterandexpressesinsmallletter(n+,n-).Heavyionsarethoselightioncombinedwithdustorfogformheavyion,expressesas(N+,N-).TheconcentrationoflightionorratioofN/ncanbeservedasindicatorsofaircleanness.

ΣN±/Σn±>50indicatesdirtyofair.Moreover,eitherN+orN-shouldnotexceed106/cm3.二.Healtheffectsofatmosphericpollutiononhumanbody1.DefinitionofairpollutionInfactnoairisfreefromforeignsubstance.Soairpollutionisdefinedas,whenaircontainsanexcessiveamountofforeignsubstances,whichbringharmfuleffectonthewellbeingofhumangroupsorcausedamagetopropertyoftheplantoranimallife.Onlyinthiscasewecandefineasairpollution.大氣中的污染物有：一次污染物（primarypollutant）：直接來源于污染源的污染物，如SO2、H2S、CO、CO2等。二次污染物（secondarypollutant）：由一次污染物在大氣中與其他化學物質發生化學反應、或在太陽輻射線作用下發生光化學反應而形成的新的污染物，如SO3、H2SO4、NO2、HNO3、醛、酮、過氧乙酰硝酸酯等。2.SourcesofairpollutionSourceofairpollutioncanbedividedinto3groups.1)Industrialandagriculturalprocess①IndustrialprocessIndustrialprocessarevariousgreatly,theyusedifferentrawmaterial,dischargedifferentwaste,whichexertdifferenteffectsonhumanbeing.Amongindustrialprocessthemostcommononeareburningfuel.Apartfromcombustionprocesssmeltingplant（冶煉）dischargeheavymetals:PbandCd.Aluminumplantdischargefluorine,fluorinehydride.Aboutwhichwearenotabletolistthemindividually.②FuelcombustionAlmostallkindofindustrialprocess,includingsmeltingprocess,powerstation,cementplant,machinemanufactoryplant,fuelcombustionarenecessary.

Whencoalisburned,themineralsincoalaftercombustionturntobeslag,orflyash.CincoalconvertstoCO2orCO.Ifcombustionisincompletealargenumberofhydrocarbonareproduced,suchassoot（煙塵）,tar（焦油）,polycyclicaromatichydrocarbon,andbenzopyrene,mostofwhicharecarcinogenic.2)Transportation

Train,ship,aircraft,motorvehiclesburngasolineordieseloilanddischargeCH,NOx,Pb.Pbcomesfromtetra-ethyllead[Pb(C2H5)4]whichisananti-knockagentaddedintogasolinetomakeittobeburnmoreefficiently.AftercombustionitescapetoairintheformofPbvapororPbOsmoke.Transportationisnowthemajorairpollutionsourceindevelopedcountries.3)DomesticcookingrangeCookingandspaceheatingusefuel,thepollutantsfromwhicharesimilartofuelcombustion.Comparedwithindustrialprocess,citydwellerburnlessfuel,howeverdomesticchimneyforcookingareenormousinnumberanddistributeextensivelyamongcityandarenearertoresidence.Therefore,insomecircumstancetheymaybemoreimportantthanindustrialprocess.4)Othersources大氣污染物的種類一次污染物二次污染物氣態污染物大氣顆粒物≤100μm，TSP

≤10μm，IP

≤2.5μm，細顆粒物（易進入肺泡，攜帶重金屬，危害極大，肺癌）

≤0.1μm，超細顆粒物）3.HazardofAtmosphericPollutionIwouldliketomakeamoredetaileddiscussiontosumupthehazardofatmosphericpollutioningeneralandonlygiveabriefoutlineabouttheindividualairpollutant.

ONE:DirectHazard

I.Acuteeffect(airpollutionepisode)Since19century,aseriousoftragediesduetopublicnuisancehadhappened.1.Smogepisode(1)Coalcombustionsmogepisode①Meusevalleysmogincident②Donorasmogincident③Londonsmogincident(2)PhotochemicalsmogepisodeLosAngelesphotochemicalsmogincident

(1)

CoalcombustionsmogepisodeSmogepisodeiscausedbyexcessivedischargeofsuspendedparticulate,SO2bycombustionoffuelundercertainmeteorologicalandtopographicconditionfavoredforaccumulationofairpollutants.Thethreemostfamoussmogepisodesofacuteillnessanddeathduetogeneralatmosphericpollutionareasfollows.①MeusevalleysmogincidentIntheMeuseValleydisasterthemeteorologicconditionsovera5-dayperiodfavoredtheaccumulationoffog,smoke,andindustrialwastesfromtheplantsinthisnarrowvalleysouthofLiege.Sixty-threepersonsandsomecattlediedonthefourthandfifthdaysafteronlyafewhoursofillness.

Thesymptomswerethoseofacuterespiratoryirritation.Deathoccurredchieflyamongelderlyandillpersons,althoughsomeillnessoccurredinapparentlyhealthyadultsandchildren.Autopsiesonsomeofthecattleshowedirritationoftherespiratorytract.

ThecauseoftheMeuseValleydisasterwasneverdeterminedsincenoairanalyseswereperformedduringthesmogperiod,butthescientistswhoinvestigatedtheconditionsafterthedisasterbelievedthatirritantgases,especiallysulfurandfluorinegases,probablywereresponsiblefortheillnessanddeaths.②DonorasmogincidentIntheDonoraepisodestagnantmeteorologicconditionsandlowtemperatureinthevalleyledtothesmogwhichlasted4.5days.Amarkedincreaseinillnessbeganonthethirdday,and17deathsoccurredonthefourthday.Altogether20personsaged52to84yearsdied,andmanyothersbecameseverelyill.

Pre-existingdiseaseofthecardiorespiratorysystemwaspresentinthemajorityofthefatalcases.Systemsoftheillnessincludedirritationoftherespiratorytractandothermucousmembranes.Autopsiesofthreecasesshowededema,hemorrhage,purulentbronchitis,andbronchiolitis.

③LondonsmogincidentInLondonduringtheperiodDecember5to8,1952,apeculiarlydensefogoccurred.LondonlocatedinbasinareanearThamesRivervalleywhereairpollutantsisdifficulttobedispersed.Thensettledown,andaccumulatedreachsuchahighlevelascausingacuterespiratorysymptoms,irritationtotheeye,respiratorytract,causecough,edemaofthelung.

Excessillnessbecamenoticeableonthethirdandfourthdaysofthefog.ExaminationofthemortalityinLondonduringandfollowingthisperiodandcomparisonwithpreviousyearsindicatedthatapproximately4,000deathscouldbeattributedtothefog.Theincreaseindeathsparalleledanincreaseintheconcentrationofsulfurdioxideandsmokeintheatmosphere.Thedeathsdecreasedsubsequenttothefallintheconcentrationofthesesubstances.

Themajorityoftheexcessdeathsoccurredininfantsandelderlypersonsandwasattributabletodisordersoftherespiratoryandcirculatorysystems.Theyareknownas"highriskgroup",andaremajorobjectinmonitoringhealtheffect.Autopsiesofsomefatalcasesshowededema,hemorrhageinthelung,purulentbronchitisandbronchiolitis.Anumberofdomesticanimalsalsowereseverelyaffected.

Thespecificcausativeagentswerenotclear.Theaverageconcentrationofsulfurdioxideintheair,increased,thehighestvaluerecordedbeing1.34ppm.ComparablebutlessseriousepisodesoccurredinLondonseveralothertimes.

(2)

PhotochemicalsmogepisodeNitrogenoxidesandhydrocarbonsdischargedbymotorvehicles,whenexposedtoultravioletradiation,experiencedaphoto-oxidizingprocessandformedphotochemicaloxidants.

Theyarehighlyoxidativeandirritatingsmog,causeirritationtotheeyeandrespiratorytractandinducecough,lungedema,andcentralnervoussymptom.

LosAngelesphotochemicalsmogincidentPhotochemicalsmogepisodeinLosAngeleshadhappenedseveraltimesinthehistory.Themostseriousincidenthappenedin1955.DuringtheepisodetheairtemperatureinLosAngeleswashigherto37.8degreeforcentigradeandlastedmorethanoneweekperiod,whichisfavoredtheaccumulationofphotochemicalsmog.Themortalityobviouslyincreasedinthepersonsover65yearsinLosAngelesduringthisperiodandinaverage70to317personsdiedeachday.Themajorityofthedeathswasattributedtoasthmaandbronchitis.Characteristicsoftwosmogepisodes

CoalcombustionsmogepisodePhotochemicalsmogepisodePrincipalairpollutants

FuelcombustionsmogSuspendedparticulateandSulfurdioxideMotorvehicleexhaustsHydrocarbonsandnitrogenoxidesMeteorologicalconditionLowtemperatureTemperatureinversionColdseasonHightemperatureStrongultravioletradiationSummerorautumnseasonTopographicalconditionValleyorbasinHighlatitudesLargecitieswithalotofhighbuildingsBelowsixtydegreesnorthorsouthlatitudesClinicmanifestationAcuterespiratoryirritationIrritationtoeyeandrespiratorytractHighriskgroupelderlyandinfantsPersonswithcardiovascularandpulmonarydiseasePersonswithcardiovascularandpulmonarydisease煤煙型煙霧事件光化學煙霧事件污染來源煤和石油制品燃燒石油制品燃燒主要污染物顆粒物、SO2、硫酸霧NOx、VOCs、O3、PANs發生季節及時間冬季、早晨夏秋季、中午或午后氣象條件氣溫低、風速低、濕度高、有霧氣溫高、風速低、濕度低、天氣晴朗、紫外線強烈地理條件河谷或盆地易發生南北緯60度以下地區易發生癥狀咳嗽、胸痛、呼吸困難，伴有惡心嘔吐、發紺等，死亡原因多為肺炎和心臟病眼睛紅腫流淚、咽喉痛、咳嗽、呼吸困難、頭痛、疲勞感和皮膚潮紅、嚴重者心肺功能衰竭易感人群老年人、嬰幼兒及心肺疾病患者心、肺疾病患者2)Industrialaccident(1)LeakingaccidentofMethylIsocyanate(MIC)inBhopal(2)RadioactivepollutionaccidentofnuclearpowerstationinChernobyl(3)AccidentalgasblowoutinKaiCountyofChongqing(1).LeakingaccidentofMethylIsocyanate(MIC)inBhopalTheaccidentalreleaseof30tonsofmethylisocyanatevaporintotheairoftheshantyvillageofBhopal,India,onDecember3,1984,killedanestimated3000peoplewithinhoursoftherelease,withanother200,000injuredand/orpermanentlyimpaired.

(2).

RadioactivepollutionaccidentofnuclearpowerstationinChernobylTheChemobylaccident(April26,1986)wastheresultofeffortstoconductatestontheelectricalcontrolsystem,whichallowspowertobeprovidedintheeventofastationblackout.Basically,therewasarapidincreaseinthereactorpower.Partofthefuelinthepressurizedwaterreactorwasvaporized,resultinginanexplosionthatblewthereactorcoreapartanddestroyedmuchofthecontainmentbuilding.Theestimatesofthesignificantradionuclidesforhealtheffectsreleasedduringtheaccidentareiodine(131I),ruthenium(103Ru),cesium(137Cs)andcobalt(60Co).

史上最可怕的核事故：切爾諾貝利驚魂20年

1986年４月26日１:23，

Theaccidentcausedthedeathswithindaysorweeksof30powerplantemployeesandfiremen(including28deathsthatwereduetoradiationexposure).During1986,220,000peoplewereevacuatedfromareassurroundingthereactor,and,after1986,ofabout250,000peoplewererelocatedfromwhatwereatthattimethreeconstituentrepublicsoftheSovietUnion:Belarus,theRussianFederation,andUkraine.

(3).AccidentalgasblowoutinKaiCountyofCongqingAsuddeneruptionofgasfromawellbeingdrilledinKaiCountyofCongqing,onDecember23,2003.Thesignificantgasesforhealtheffectseruptedduringtheaccidentaremethane,ethane,hydrogensulfideandcarbondioxide.Intheaccident,about90000peoplewereeffected,nearly65000localresidentswereevacuatedfromareasintheemergency,42847personswerereceivedthemedicaltreatment,and2155personswereinhospital.Theaccidentledtothedeathof243persons.重慶市開縣高橋鎮的一礦井2003年12月23日22時左右發生天然氣“井噴”。事故發生時富含硫化氫和二氧化碳的天然氣噴至30米高，非常猛烈。重慶發生天然氣井噴事故

死亡人數243人

在醫院接受治療的中毒患者

致死的家禽II.Chroniceffect1)Inflammationofrespiratorytract2)ChronicObstructivePulmonaryDiseases(COPD)Thoughairpollutionepisodefocusgreatattentionofpublics,butitisfarlessfrequentthanchroniceffects,thatistosaychroniceffectismoreimportantduetoitsenduranceandextensiveness.LongtermexposedtoSPandSO2increasetheprevalencerateofCOPD,includingchronicbronchitis,asthma,emphysema,agroupofrespiratorydiseaseswhichhasmultipleetiologicfactor,suchascoldweather,airpollution,smoking,indoorairpollutionetc,amongwhichairpollutionplaysamajorrole.3).Bronchialasthma(allergicreaction,

Yukkaichiasthma)Althoughbronchialasthmaisachronicdisease,attacksoccurintermittentlyandmayvaryinintensityandduration,rangingfrommildtosevereandevenresultingindeath.Increasedairpollutionlevelscancontributetoacuteasthmaticattacks.AnearlystudyoftheDonoratragedyrevealedthat87.6%ofasthmaticindividualsinthatareaexperiencedsymptoms.

Moststudiesofthecorrelationbetweenincreasedairpollutionandasthmaticattackshaveusedsubjectivereportsfromsufferersoremergencyroomstatistics.Theproblemofidentifyingspecificcausesofsuchattacksiscomplicatedbyanumberofotherfactors:timeofdayanddayofweek,temperature,humidity,andemotionalstress.

InplacewhereSOxreachahighlevel,aspecificasthmamayoccur,whichisnamedbyitscity,Yukkaichiasthma.Othercities,suchasYukohamaandLosAngeles,alsofoundthiskindasthma.Theappearanceandtreatmentofsuchasthmaisnotdifferentfromusualbronchialasthma,butitisanauto-immunedisease,causedbySOxservesashapten,causedegenerationofalveolarprotein,theninitiatereactionofhypersensitivity.

4)ReducethebodyimmunityIII.Remoteeffects(1.Cardiovasculardisease,2.lungcancer)Asyoumayknowthemortalityoflungcancerhasbeenincreasingrapidlysince1930intheworld.Inaveragethereisa1.5timeincreaseindeathrateoflungcancer.Smokingisoneoftheprovenetiologicagents.Thequestioniswhetherairpollutionalsoresponsiblefortheincrease.Mostscientistbelieveit,butsomedoubt.Therearealargenumberofevidences,whichsupportthehypothesisthatairpollutionisanetiology.

EnvironmentalCarcinogen:Thereareanumberofchemicalsknownascarcinogenexistedinurbanair.Somecancausecancerinlaboratoryanimal,someofwhichhavethedefiniteepidemiologicalevidence.Theprovingcarcinogeninaircanenumerate:1.PAH---BaP2.Aromaticamine（芳香胺）----nitrosamine3.Heavymetal---Cr,Ni,As4.Asbestos（石棉）5.PM2.5大氣污染的直接危害一、急性危害1.煙霧事件（煤煙型煙霧、光化學煙霧）2.生產事故（異氰酸甲酯、核污染、開縣）二、慢性危害1.影響呼吸系統功能2.引起變態反映3.降低機體免疫力三、心血管疾病四、肺癌TWO:Indirecthazardofairpollution(1)ProductionofgreenhouseeffectCause:

Owingtotherapiddevelopmentofindustries,largeamountofenergyresourcesisconsumedeachyear,consequentlydischargegreenhousegasincreasesyearbyyear.Greenhousegascanabsorbinfraredray,reduceheatemissiontotheouterspace,asaresultairandseawatertemperatureisincreasing.Greenhousegasincludes

carbondioxide(CO2)chlorofluorocarbons(CFCs)methane(CH4)nitrogenmonoxide(N2O)AmongthesegasesCO2contributesto55%CFCsto24%CH4to15%N2Oto6%Influenceonpopulation

Sealevelelevates:HightemperatureleadsthemeltingoftheicebergsontheNorthandSouthPole.Manycitiesintheworld,especialcoastalcities,willbeflooded(drown).Someinfectiousdiseasewillincrease.Infectiousdiseases、insect-bornediseasesthatrelatetohightemperature，Heatrelatedillnesses(2)OzonedepletionCause:Ozonedepletionisthemajoreventofairpollution,whichfocusthegreatattentionamongpublicandauthorities.Ozonedepletionisduetotheincreasingproductionand