00The Occurrence of Haze in Malaysia A Case Study

TheOccurrenceofHazeinMalaysia:ACaseStudyinanUrbanIndustrialAreaAIMANSOLEIMAN,1,2MAZLANOTHMAN,1AZIZANABUSAMAH,2NIKMERIAMSULAIMAN,2andMIROSLAVRADOJEVIC3Abstract—KlangValley,aheavilyindustrializedurbanareainMalaysia,hasexperiencedseverehazeepisodessincetheearly1980s.TotalSuspendedParticulatematter(TSP)isusedinstudyingthisphenomenon.Threeseverehazeepisodesduringtheearly1990sarereviewed;August1990,October1991,andAugust–October1994.Thenatureoftheseepisodes,theirpossiblecauses,andtheirmajorfeaturesarediscussed.Meteorologicalconditionsassociatedwiththeseepisodeswereanalyzed.Resultsofthestudyindicatethatstabilityandtrappingofparticlesarethemainfactorsaffectingthepollutionduringhazeperiods.Maximumtotalsuspendedmatter(TSP)wasrecordedinOctober1991.TheAugust–October1994episodewasthemostpersistentandleastaffectedbymeteorologicalvariables.Analysisofwinddirectiondatashowedthatsoutherlyandsouthwesterlywindscoincidedwiththeworsthazeperiods.Keywords:Haze,TSP,temperature,wind,rainfall,Malaysia.IntroductionHazeisdefinedasthepresenceoffineparticles(0.1–1.0lmindiameter)dispersedatahighconcentrationthroughaportionoftheatmospherethatdiminishesthehorizontalvisibility,givingtheatmosphereacharacteristicopalescentappearance(MMS,1995).Particles,whichareofrespirablesizes,areofconcernbecauseoftheirnegativeeffectonhealth,aswellastheirotherenvironmentalimpacts.Particles10lmcanaffectmeteorologicalprocesses(visibilityandsolarradiation),andtheycanbeinvolvedinchemicalreactionsintheatmosphereproducingsecondarypollutants.ThehazephenomenonintheKlangValleyregionisanimportantandseriousproblem.Sincetheearly1980sKlangValleywasreportedtoexperiencehighconcentrationsofparticulates.Unusuallythickhaze,whichoccurredduringSeptember1982(SHAM,1984),wasthefirsttoattractagreatdealofpublic1DepartmentofPhysics,NationalUniversityofMalaysia,43600,Bangi,Malaysia.2AirPollutionResearchUnit(APRU),DepartmentofChemicalEngineering,UniversityofMalaya,50603,KualaLumpur,Malaysia.E-mail:[e-mail]3DepartmentofChemistry,UniversityofBruneiDarussalam,B.S.B.BE1410,BruneiDarussalam.Pureappl.geophys.160(2003)221–2380033–4553/03/020221–18
Birkha¨userVerlag,Basel,2003PureandAppliedGeophysicsattentionandtobeextensivelyreportedinthelocalmedia.Subsequently,KlangValleyexperiencedepisodesofseverehazeconditionslastingforvaryingperiodsoftime.TheMalaysianMeteorologicalService(MMS)reportedthesehazeepisodeswhichoccurredduringApril1983(CHOWandLIM,1984),August1990(SHAMetal.,1991),June1991,October1991(CHEANGetal.,1991),AugusttoOctober1994(MMS,1995),andAugusttoOctober1997.HazeepisodesintheKlangValleywereusuallyassociatedwithdryweatherwhichsuppressedconvection.Adrylayerinthelowertroposphereduringhazeepisodeswasobserved,anditwasspeculatedthatthedrylayercouldactasalidforverticalmixingandhencecontributetothetrappingoftheemittedpollutants(SAMAH,1995;SHAMetal.,1991).IntheKlangValleyregiontherearetwokindsofhaze;shallowlocalizedhazeanddensehaze.Theformer,whichusuallyoccursinurbanizedareas,arisesfromtrappingofpollutantsfromanthropogenicemissionsinresponsetostabilizationoftheatmosphere,whilethelatteristhoughttobeduetodifferentreasons(MMS,1995)listedbelow:
Theadvectionbyprevailingwindsofsuspendedashparticlesfromlarge-scaleforestfiresandopenburninginIndonesia(April1983,October1991,AugusttoOctober1994,andAugusttoOctober1997),
thehazeconditionscombinedwithlocalopen-burning(August1990),and
theinjectionofsuspendedashparticulatesfromvolcaniceruptionssuchasMountPinatuboinJune1991(MMS,1995).TheaimofourworkistoreviewthethreeseverehazeepisodesexperiencedintheKlangValleyduringtheearly1990s,namely:August1990,October1991,andAugusttoOctober1994.Sourcesandconcentrationsofparticulatematter,aswellasmeteorologicalconditionsassociatedwitheachofthehazeepisodesareinvestigated.Thepollutanttrappingmechanismisdiscussed,andacomparisonbetweentheseverehazeepisodesispresentedonthebasisofmeteorologicalvariables.DescriptionoftheStudyAreaOccupyingacentrallocationontheWestCoastofPeninsularMalaysia,theKlangValleyregionisahighlypopulatedandindustrializedurbanarea.Thisregionincludesthefollowing:KualaLumpur,thecapitalcityofMalaysia,PetalingJaya,adenselypopulatedandindustrializedarea,ShahAlam,thestatecapital,KlangandPortKlang(Fig.1).Theentireareaisfullydeveloped,withmanymanufacturingindustriesproducingarangeofproductsfromelectricalappliancestocarsandmotorcycles.Powergeneration,ironsmelting,chemicalindustryandvariousconstructionactivitiesarealsolocatedintheregion.Thisregionhasbeenshowntohaveahighpotentialforpollutionbecauseoftheincreaseinpollutionsourcesfollowingrapidurbanizationandindustrialexpansion222AimanSoleimanetal.Pureappl.geophys.,(SHAM,1987).TheKlangValleyissurroundedbyhillstothenorth,eastandsouth,andthisimpedesthehorizontaltransportofsurfacegeneratedpollutants.Hence,meteorologicalvariableshaveastronginfluenceontheconcentrationandtransportofTSP.ThesefactorshaveresultedintheKlangValleybecomingthemostpollutedareainMalaysia.SHAMetal.(1991)reportedthatthemainsourcesofpollutantsinthisareaaremotorvehicleandindustrialemissions.Moreover,thedevelop