PM2.5英文介绍ppt课件

PM2.5,1,PM，anabbreviationforParticulateMatter,referstoliquidorsolidparticlessuspendedintheair.Dependingontheiroriginandvisualappearance,aerosolshaveacquireddifferentnamesintheeverydaylanguage.Dustreferstosolidairbornematerial,dispersedintoaerosolfromgrainypowderssuchassoil.Combustionprocessesproducesmokeparticles,buttheincombustibleresiduesofcoalarecalledflyash.Intheearlydays,airpollutionhadtheappearanceofbothsmokeandfog,sothetermsmogwascreated.Intheopenatmosphere,thevisibilitymayoftenbereducedbyregionalhaze,originatingfromvariousnaturaloranthropogenicsources.Neitherwaterdropletsoffogandclouds,snow,rain,sleet(hydrometors)nordustparticleslargerthan100um(blowingsand)areconsideredtobeparticulatematter,Whatis“”?,2,WhatisPM2.5？,ThenamePM2.5denotesthatitincludesallparticulatematterthathasanaerodynamicdiameterof2.5micronsorsmaller.2.5micrometersisapproximately1/30thesizeofahumanhair.PM2.5alsocalledfineparticulatelodgesdeeplyintothetissueofthelungandisnoteasilydispelled.Itcausesbothrespiratoryandcardiacillness,andhasbeenlinkedtoprematuremortalityeveninhealthyindividuals.,3,4,PMFormationintheAtmosphere,ThesourcesofPM2.5includefuelcombustionfromautomobiles,powerplants,woodburning,industrialprocesses,anddiesel-poweredvehiclessuchasbusesandtrucks.Thesefineparticlesarealsoformedintheatmospherewhengasessuchassulfurdioxide,nitrogenoxides,andvolatileorganiccompounds(allofwhicharealsoproductsoffuelcombustion)aretransformedintheairbychemicalreactions.,5,PM2.5HealthEffect,Increasedlevelsoffineparticlesintheairasaresultofanthropogenicparticulateairpollutionisconsistentlyandindependentlyrelatedtothemostseriouseffects,includinglungcancerandothercardiopulmonarymortality.Thelargenumberofdeathsandotherhealthproblemsassociatedwithparticulatepollutionwasfirstdemonstratedintheearly1970sandhasbeenreproducedmanytimessince.PMpollutionisestimatedtocause22,000-52,000deathsperyearintheUnitedStates(from2000)and200,000deathsperyearinEurope.,6,Whoneedstotakestepstoreduceexposure？,Everyoneneedstotakestepstoprotectthemselveswhenpollutionlevelsare“hazardous”andabove.SomepeopleareathigherriskfromPM2.5exposure.Peoplemostatriskfromparticlepollutionexposureincludethosewithheartorlungdisease(includingasthmaandchronicobstructivepulmonarydisease-COPD),olderadults,andchildren.Researchindicatesthatpregnantwomen,newborns,andpeoplewithcertainhealthconditions,suchasobesityordiabetes,alsomaybemoresusceptibletoPM-relatedeffects.,7,TheGlobalPM2.5pollutionindexmapwasdrawnbyCanadianscientistsaccordingtoNASAsatellitedata.Inthemap,colorschangefromdarkbluetolightblue,yellowanddarkred,whichrepresentsthattheconcentrationofPM2.5becomesmoreandmorehigh.FromthemapwecanseethatairpollutionhasbeenanunusuallyaustereprobleminChina,especiallyinthenorthandeast.,8,Noteasytomonitor,Althoughtightermonitoringstandardswillsoonbeintroducednationwide,itwillnotbeeasyforBeijingandothercitiestomeetacceptedPM2.5standardsandthenfurthercontrolpollution.,Thebiggestproblemformonitorisfinancing.PM2.5monitoringequipmentusuallycosts80,000-380,000yuan($12,710-60,370).Apreliminaryestimateshowsthatmorethan338prefecture-levelcitieswillhavetoinvestmorethan2billionyuan($318million)onthenewequipment,。,9,Hardtocontrol,Asamulti-sourcepollutant,PM2.5istrickytotechnicallycontrol.ResearchshowsthatoverhalfofPM2.5emissionsarenotdirectlyemitted,butareoxidationsofotherairpollutants.Slowthenumber