chapter8AirPollutionandControl.ppt

Chapter8AirPollutionandControl AtmosphericfactorsTypes sourcesandeffectsofairpollutantsGlobalairpollutionIndoorairqualityAirsamplingandmeasurementAirpollutioncontrol Background FireIndustrialrevolution neweraofairpollutionAirpollutionepisodes 八大公害事件 percapitadeathrateRespiratorydiseasesincludinglungcancer 8 1atmosphericfactors meteorology MeteorologyCompositionofatmosphereAtmosphericlayersEffectsofweather 8 1 1Meteorology WeathercirculationpatternsTheimpactonairpollutioncontrolrequirements small scalecirculationpatternsGlobalairpollutionproblems large scaleweatherpatterns 8 1 2Compositionofatmosphere Nitrogen78 Oxygen21 Inertgasargon0 9 carbondioxide methane hydrogen helium neon ozoneothergasesintraceamounts therest0 1 8 1 3Atmosphericlayers Troposphere thelowermost 95 ofthetotalairmass mostairpollutionproblemsoccur weatherpatternsdevelopStratosphere stable morenaturallyoccurringozonethanthetropospheremesosphereIonospherethermosphere Figure13 2 Temperaturegradienttemperaturevs altitudeDecreaseswithincreasingaltitudeIncreasesincreasing 8 1 4effectsofweather Airpollutantsaremixed dispersed anddilutedwithinthetropospherebymovementofairmasses bothhorizontallyandvertically dependentonlocalaswellasregionalweatherconditions Horizontaldispersionofpollutants Windspeedanddirection selectsitesfornewindustrialfacilitiesorpowerplants tominimizelocalairpollutioneffects upwindlocation Windrose apictureofthespeedanddirectionfromwhichthewindtendstocome prevailingwinds Figure13 3 Figure13 3 Positionsofspokes winddirectionTotallength percentageoftimethatthewindwasblowingfromthatdirectionShadedsegments thepercentageoftimethewindwasblowingattheindicatedspeedCalm 16directions Wind pollutants CombinedeffectsoftemperaturegradientsandtherotationofEarthCirculationpatterns topography dailyandseasonalvariationsinsurfaceheating proximitytolargebodiesofwaterandtomountains andcloudcoverEquator PolesSoilandrock WaterSteel concrete andmasonry heatisland self containedcirculationpattern VerticalDispersionofPollutants Atmosphericstability verticalmixinganddispersionAconditionofatmosphericinstabilityispreferabletoastablecondition Temperatureinversion extremelystableatmosphere themajorcausesofairpollutionepisodes P 453Problem1and2 Howtogetthestability Comparetheenvironmentallapseratewiththeadiabaticlapserate stableorunstableatmosphere Figure13 4environmental prevailing ambientlapserate therateatwhichtheairtemperaturedrops crucialimportancewithregardtoatmosphericstabilityFactors geographicfeatures wind andsunlightOthermethods Adiabaticprocess aphysicalprocessinwhichthereisnoheattransferthefirstlawofthermodynamics dryadiabaticlapserate 1 per100mResults Superadiabaticorsubadiabatic strongorweak stableatmosphere environmentallapserates Figure13 5 Temperatureinversion AnincreaseinactualairtemperaturewithincreasingaltitudeextremelystableatmosphereCause avarietyoflocalmeteorologicalconditions anywhere certain increasethefrequencyanddurationThreetypes frontalinversions subsidenceinversions radiationinversions Atrelativelyhighaltitudesfrontalinversions warm cold notimportantsubsidenceinversions long lasting ofmajorimportance fumigatingconditionmaydevelopneargroundlevel veryhighground levelpollutantconcentrationsAtlowaltitudesradiationinversions fumigatingconditionsarecommon notlong lasting Howtocalculateandpredictground levelconcentrationsofpollutantsdownwindfromsourcessuchassmokestacks Mostcomputerprograms GaussiandispersionsequationAvarietyofsimplifyingassumptions auniformsteadywind aconstantemissionrate flatterrain aconservativepollutant uncertainresults ananalyticaltoolforcomparingvariouspollutioncontrolstrategies 8 2Types sourcesandeffectsofairpollutants Airpollution thepresenceofcertainsubstancesintheairinhighenoughconcentrationsandforlongenoughdurationstocauseundesirableeffectsAnthropogenic causedbyhumanactivity Criteriaairpollutants USA five 9inChina primarycriteriapollutants sulfurdioxide nitrogenoxides andcarbonmonoxide solidorliquidparticulates smallerthan10micrometer andparticulateleadsecondarycriteriapollutant ozoneHazardousairpollutantsEffectsofambientairpollution 8 2 1Criteriaairpollutants Sulfurdioxide 25millionstons a USA Nitrogenoxides 20millionstons aCarbonmonoxide 100millionstons aParticulatematter TSP7andPM10 LeadparticulatesOzoneandphotochemicalsmogBenzopyrene Fluoride环境中的化学 mpg SulfurDioxide SO2 LondonSmog Characteristics colorlesswithsharp chokingodorSources fossilfuelsoxidized burned 80 electricutilitypowerplants mobilesources petroleumrefining coppersmelting themakingofcement SulfurDioxide SO2 LondonSmog coined Effect SO2 primarypollutant sulfurtrioxide SO3secondarypollutant sulfuricacidmist H2SO4 wetdeposition acidrain ordrydeposition withoutprecipitation LondonSmogControl fueldesulfurization fluegasscrubbing othercontrols NitrogenOxides LosAngeles Sources combustionoffossilfuel mobilesources temperature oxygen FormsandCharacteristics NO2 nitrogendioxide pungent irritatinggas reddish brown ofgreatestimportanceNO nitricoxide colorless initiallyformofmostemissions Effects NO NO2 hydrocarbons photochemicalsmog LosAngelesNO2 hydroxylradical OH nitricacid HNO3 acidrainInternalcombustionengines controlCO increasingtheairsupplyandraisingthecombustiontemperature maketheNOxproblemworse实验 mpg NitrogenOxides LosAngeles CarbonMonoxide Characteristics colorless invisible odorless andtastelessSources incompletecombustionofthefuel temperature time oxygen highwayvehicles residentialheatingsystems industrialprocesses exceptpowergeneratingplants ParticulateMatter Characteristics extremelysmallfragmentsofsolidorliquiddroplets distinguishedonthebasisofparticlesize aerodynamicdiameter andsourceSources industrialprocesses coal oroil burningpowerplants residentialheatingsystems andhighwayvehicles Classifiedaccordingtotheirsizeandphase Figure13 7 SuspendedSolid1 100micrometerinsize dust10micrometer sprayanysmallparticles liquidorsolid suspendedinair aerosol LeadParticulates Characteristics Toxicmetal Fume 0 5micrometerinsizeSources Gasolinecontainingalead baseantiknockadditive tobereplaced Petroleumrefiningandsmeltingoperations batteryrecovery andotherindustrialactivitiesEffect youngchildren OzoneandPhotochemicalSmog Sources secondarypollutants NO2andVOCs vehiclesEffects mostabundantofthephotochemicaloxidants photochemicalsmog LosAngeles temperatureinversion lotsofhighwaytrafficandamplesunshine 8 2 2Hazardousairpollutants HAPs Sources steadyandgradualemission suddenandoftencatastrophicaccidentsGreatestrisks heavilypollutedandindustrializedurbanareasDepositedintolakes GreatLakes 北美五大湖 苏必略 休伦 伊利 安大略和密歇根湖 example Bhopal AcityofcentralIndianorth northwestofNagpur Foundedintheearly18thcentury itisanindustrialandtradecenter In1984atoxicgasleakataninsecticideplantkilledapproximately3 000people 博帕尔印度中部一城市 位于那格浦尔西北偏北 建于18世纪初期 是工业和贸易中心 1984年 一家杀虫剂工厂的毒气泄露导致将近3千人死亡 博帕尔污染 对周围的人和环境造成严重伤害的工业灾难 尤指在发展中国家 SomeHAPs Asbestos 石棉lungdiseases cancerBenzene 苯carcinogenBeryllium 铍radioactiveMercury brainandkidneyVinylchloride 乙烯基氯Radionuclide 放射性核物质Arsenicandothers 砷 8 2 3Effectsofambientairpollution economicimpacts Healtheffects acute chronic ortemporary respiratorysystem pulmonaryOthereffectsofairpollutionMaterialobjectsTrees flowers frits andvegetablesAtmosphereitself HealthEffects ThresholddosageTotalbodydoseExposuretimeSynergisticeffects 8 3GlobalAirPollution ScalesofpollutanttransportGlobalwarmingDepletionofstratosphericozoneAciddeposition 8 3 1scalesofpollutanttransport Local uptoafewkilometersRegional upto1000kmContinental uptoafewthousandkilometers interchangeofpollutantsGlobal morethanafewthousandkilometers potentiallythroughouttheentireatmosphere 8 3 2GlobalWarming natural anthropogenic MechanismGreenhousegasesPotentialimpacts mechanism Wavelength temperatureoftheenergyradiatedbyobjectsRadiationfromthesurfaceofthesun Most visiblelight 45 reachestheEarth ssurface 15 absorbedbytheatmosphere 40 reflectedbackintospacebycloudsShorter ultravioletlight absorbedinthestratosphereLonger infraredradiation reradiatedbyearth playsakeyroleinthegreenhouseeffect mechanism Infraredradiation absorbedbytheatmosphere primarilybywatervaporandcarbondioxidemolecules thelowerlayeroftheatmosphere thetroposphereiswarmedWarmairitselfalsoradiatesinfraredheat goesbackdowntowardthegroundandkeepsitwarmerthanitwouldotherwisebeResult lowest warmest troposphere mechanism Wattspersquaremeter W m2Equilibrium theamountofheatemittingfromEarth ssurface 390W m2 theamountofheatthatEarthreradiatesbackintospace 240W m2 150W m2Balancepoint composition constantChange increaseoftheamountofCO2 warmer newbalancepoint anthropogenicgreenhouseeffect Unit W m2 IncomingSolarRadiation342 107 77 reflectedbyclouds atmosphere aerosol 30 reflectedbysurface 168 absorbedbysurface 67 absorbedbyatmosphere InfraredRadiation IR 390 absorbedbygreenhousegases 235 165 30 40 throughatmospherewindow Backradiation324 390 235 absorbedbyGreenhousegases 67 absorbedbyatmosphere 24 thermalreflected 78 evapotranspiration temperaturerising 324 168 Yellow SolarRadiation InfraredRadiation IR UltravioletRadiation Compositionchanges greenhousegases Carbondioxide CO2 氟利昂 CFCchlorofluorocarbon NitrousOxideN2O Watervapor methane CH4 ozone O3 气体浓度 10 6年增长 生存期 年温室效应现有贡献率 CO23550 450 200155CFC0 000852 250 1023400 1500024CH41 7140 812 171115NOx0 310 251202706 greenhousegases CO2 increasingrate2 asincethelate1950s 90 occurinthenorthernhemisphere oil50 coal1 3 naturalgas destructionofforests 60 CFCs 25 muchefficientnitrousoxide 30timesmorepotentthanCO2 electriccars ozone othertracegases Potentialimpacts BasedontheGCMs createamoreactivehydrologiccycle increasingcloudinessaswellasprecipitationTwoimportantpotentialimpacts onsealevelsandonecosystems sealevelsrise 0 3 1 4mbytheyear2030 economicandsocialhardshipincoastalareasallovertheworldfloodingforlow lyingcoastalareasincreasebeacherosionproblemschangetheshapeofthecoastlinesaltwaterintrusionintocoastalwetlandsorgroundwateraquifersmoreoften Since1979 thesizeofthesummerpolaricecaphasshrunkmorethan20percent IllustrationfromNASA Ecosystem agricultureandforestgrowth Influenceplantgrowthanddevelopment stimulatesphotosynthesisanddecreaseswaterlossesfromtranspiration watercycle climateChangesinprecipitationandclimate newstressestoagriculturalandforestecosystems pests disease drought org flood Otherimpacts IncreasethechancesofdiseaseinhumansandanimalsRequireadjustmentsinfloodplaindesignations publicwatersupplies buildingcodes engineeringandarchitecturalprojects andotherimportantareasthataffecthumanlifestyles InternationalControlEfforts 1990Geneva12Europeannations1992RodeJaneiro stabilizeemissionsofgreenhousegasesat1990levels1995globalwarmingconferenceBerlinMandate1997KyotoProtocol specifictargetsandtimetablesfordevelopednations internationalemissionstrading reluctance 清洁发展机制 ppt InnovativeTechnologyforControllingGlobalWarming Twoapproaches Developalternativeenergysources nuclearandsolarpowerCutbackonenergyusethroughconservationeffortsanduseofmoreefficientautomobilesandappliancesthirdstrategyinUSA carbonsequestration 8 3 3Depletionofstratosphericozone Ozonehole anozone depletedregionMeasured byspectrographicinstrumentsonthegroundandbysatellitesEffects humanskincancer eyecataracts andsuppressionofimmunesystemresponse plantandaquaticorganismsbeharmed photochemicalsmog 谁杀死了臭氧 mpg Mechanism Characteristicsofozone unstabledelicatebalancebetweenitsformationandremovalinthestratosphere Formedasshort wavelengthUVenergyisabsorbed MolecularoxygenChlorine affecttheequilibrium speeduptherateozoneremoval CFCschlorofluorocarbons 8 3 4AcidDeposition define pH 5 6 naturalorpristineacidityofrainwater causedbyhumanactivities sulfur twice andnitrogenoxidesintotheatmosphereaciddeposition reachthesurfaceofEarthintheformofrainfall snow fog ordew wetdepositionTinyparticulatesandsettleoutofairinadryform drydeposition Effectsofaciddeposition LoweringofpHinlakesandrivers Disruptmostaquaticlife Phytoplanktonpopulationsreduced pH 5 1Commonwater dwellinginvertebratescannotsurvive pH 6 0sensitivespeciesoffish troutandsalmon harmed pH 5 5Deleteriouseffectonthereproductivecycleoffish reproductionofmostfishspeciesisunlikelywhenpH 4 0aciddeadlakes pH 3 5 Effectsofaciddeposition Publichealth corrodepipesandcauseleachingofheavymetalsintodrinkingwater accumulationoftoxicmetalsinthefoodchainFactors buffers calciumcarbonate regionalandcontinentalscaleMethodstocontrolresearchprojectseconomicincentives emissioncredits 8 4IndoorAirQuality IAQ CauseAirexchangeIAQpollutantsSickBuildingSyndrome 8 4 1Cause Mostpeoplespendthemajorityoftheirtimeindoors 90 Increasedenergyconservationmeasures lowerairexchangerates aircontaminantsaccumulate indooraircanbemorepollutedthanoutdoorairMid 1980s healthrisksrelatedtoindoorairpollutionbecameaconcern Howtocontrol StrategiesandattentionTechniques Adequateventilation limitpollutantconcentrationsReducesourcesofpollutantsAircleaners removeparticulatepollutants 8 4 2Airexchange Ratesofairexchange airchangesperhour achThreeways airexchange energy Infiltration properconstructionandinsulationtechniquesnaturalventilation higher bywindortemperaturedifferencesforcedventilation highest usingfansorblowers intermittentorcontinuous 8 4 2IndoorPollutants Types combustionproducts especiallyETS radon asbestos organicsfromhouseholdproducts formaldehyde lead biologicalcontaminantsSourcesEffects CombustionProducts ETS environmentaltobaccosmokeamixtureofmorethan4000compoundsatleast40ofwhicharecarcinogenicmanyofwhicharestrongirritantssecondhandorsidestreampassivesmoking 被动吸烟Othersources stoves spaceheaters fireplacesandchimneysPollutants CO NO2 particulates SO2 acidaerosols CombustionProducts EffectsofETS Short termexposure eye nose andthroatirritationLong termexposure 3000lungcancerdeathseachyearinnonsmokingadults especiallydangerouscombinedwithradonControl Eliminatesmokinginthehome reducewithincreasedventilationrates Radon Colorless odorless radioactivegas uraniumandradiumSources Figure13 8soilsandrocks entersabuildingthroughopenings cracks orjointsinthebasementfloororwalls accumulategroundwater householdair Radon ChemicalinertDifferentproducts riskchemicalactivedecayproducts radonprogenyattachedtoparticles lungcancerfurtherprogeny radiation lungtissuedamagedRiskdegree totalexposuretimeandaverageradonconcentrationinthehome Radon Measurementdevices charcoalcanister alphatrackdetectorpCi L picocuriesperliter WL workinglevel1WL 100pCi L ReducingradonentryintothehouseRemovingradonafterithasenteredthehouse ReducingorRemovingRadon ReducingCoverandsealInstallasubslabandperimetersoilventilationsystem Figure13 9AvoidingtheuseofbuildingmaterialsthatmaycontainradiumRemovingAerationoractivatedcarbonfiltrationVentilationoftheaffectedlivingspaceHeat recoveryventilation Figure13 10 air to airexchanger Asbestos石棉 Mineralfiber asbestosis lungscarring mesothelioma cancerofthechestandabdominallinings lungcancer occupationalexposureandhomesOrganicsfromhouseholdproductsToxic carcinogenic noknownhealtheffectSuchas eyeandrespiratorytractirritation headaches dizziness visualproblems andmemoryimpairment Formaldehyde Sources Buildingmaterialsandhouseholdproducts by productofcombustionFactors Temperatureandhumidity dehumidifiersandair conditioning increasedventilationrates reduce Effects eyeandthroatirritation nausea andrespiratorydistress cancer Lead Drinkingwaterandfood leaddustintheair fromoldlead basedpaintorcontaminatedsoiltrackedintothehouseBiologicalcontaminantsAirborne bacteria fungi viruses animaldander housedustmites pollen andothertinyformsorproductsoflifeAllergicreactions asthmaandrhinitisInfectiousdiseases influenza measles andchickenpox 8 4 3SickBuildingSyndrome Building relatedillnesses identifiedillnesses directlytracedtospecificbuildingproblemsSickbuildingsyndrome abuildingwhenmorethan20 ofitsoccupantscomplainofhealthproblemsfor2weeksormoreandthesymptomsarerelievedwhentheoccupantsleavethebuilding SickBuildingSyndrome Typicalcomplaints sneezing fatigue headache dizziness nausea drythroat andirritabilityCauses poordesign operation ormaintenanceofthecomplexmechanicalventilationsystemtosaveenergyairsupplyandreturnventsareblockedorplacedimproperlyventilationsystemitself 8 5AirSamplingandMeasurement 8 5 1ThreedistinctkindsofairsamplingSourceSampling emissionstandardsAmbientSampling airqualitystandardsIndoorSampling industrialhygienesamplingandresidentialsampling 8 5 2CollectionandMeasurement Particulates massandsizeoftheparticlesGravimetrictechnique dustfallbucketsPM10samplers hi volumesamplerFiltrationtechnique dichotomoussampler