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MODULEVII

LearningObjectivesIssuesofconcernsinairpollution:greenhouseeffect,acidrain,ozone

hole,andphotochemicalsmog.

Lecture1 Lecture2 Lecture3 Lecture4

PhotochemicalSmogPhotochemicalsmog??

Noxiousmixtureofhighlyreactiveandoxidizingairpollutantsincluding:

OxidesofNitrogen(NOx)VolatileorganiccompoundsTroposphereOzonePeroxyacetylNitrates(PAN)

GenerationMechanism

Threeingredientsrequired:

UltravioletLightHydrocarbonsNitrogenoxides

PhotochemicalReaction

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PhotochemicalReactions

1)TroposphericOzone:

SourcesExhaustgasesFromMotorvehiclesUnburntHydrocarbons

2)VolatileOrganicCompounds(VOC)

CarbonbasedmoleculessuchasAldehydes,

KetonesandHydrocarbons

SourcesPaintthinners,solventsandpetroleumconstituentsTrees:emitsisopreneandterpenes

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Methanefromtermites,cowsandcultivation

3)PeroxyacetylNitrates(PAN)

AresecondarypollutantsformedfromperoxyacidradicalsandNO2

Effectsonhumanhealth

OzoneCauseacuterespiratoryproblemsAggravateasthmaCausetemporarydecreasesinlungfunctioninhealthyadultsLeadtohospitaladmissionsandemergencyroomvisitsImpairthebody'simmunesystem

Peroxyacetylnitrate(PANs)RespiratoryandeyeirritantsMutageniccausingskincancer

Volatileorganiccompounds(VOCs)GlobalwarmingMethaneCarcinogenicbenzeneFormOzone