NPTEL

5/12/2015 NPTEL::CivilEngineeringEnvironmentalAirPollution

http://www.nptel.ac.in/courses/105102089/air%20pollution%20(Civil)/Module7/2.htm 1/3

MODULEVII

LearningObjectivesIssuesofconcernsinairpollution:greenhouseeffect,acidrain,ozone

hole,andphotochemicalsmog.

Lecture1 Lecture2 Lecture3 Lecture4

PhotochemicalSmogPhotochemicalsmog??

Noxiousmixtureofhighlyreactiveandoxidizingairpollutantsincluding:

OxidesofNitrogen(NOx)VolatileorganiccompoundsTroposphereOzonePeroxyacetylNitrates(PAN)

GenerationMechanism

Threeingredientsrequired:

UltravioletLightHydrocarbonsNitrogenoxides

PhotochemicalReaction

5/12/2015 NPTEL::CivilEngineeringEnvironmentalAirPollution

http://www.nptel.ac.in/courses/105102089/air%20pollution%20(Civil)/Module7/2.htm 2/3

PhotochemicalReactions

1)TroposphericOzone:

SourcesExhaustgasesFromMotorvehiclesUnburntHydrocarbons

2)VolatileOrganicCompounds(VOC)

CarbonbasedmoleculessuchasAldehydes,

KetonesandHydrocarbons

SourcesPaintthinners,solventsandpetroleumconstituentsTrees:emitsisopreneandterpenes

5/12/2015 NPTEL::CivilEngineeringEnvironmentalAirPollution

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Methanefromtermites,cowsandcultivation

3)PeroxyacetylNitrates(PAN)

AresecondarypollutantsformedfromperoxyacidradicalsandNO2

Effectsonhumanhealth

OzoneCauseacuterespiratoryproblemsAggravateasthmaCausetemporarydecreasesinlungfunctioninhealthyadultsLeadtohospitaladmissionsandemergencyroomvisitsImpairthebody'simmunesystem

Peroxyacetylnitrate(PANs)RespiratoryandeyeirritantsMutageniccausingskincancer

Volatileorganiccompounds(VOCs)GlobalwarmingMethaneCarcinogenicbenzeneFormOzone