Aerosols PPT

Aerosols: Tiny Particles,  Big Impact

CONTENT What is an aerosol? What are the sources of aerosols? Aerosol Size distribution  The Aerosol Aerosol Modes Atmospheric cycling of aerosols What role aerosols play in Earth!s atmosphere? atmosphere?  Three types of aerosols aerosols "hich a#ects the Earth!s climate $o" do aerosols a#ect the climate? Atmospheric Atmospheric lifetime of di#erent di#erent size particles at di#erent le%els of the atmosphere What is &global dimming& and an d ho" are aerosols in%ol%ed? Aerosol sin's

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What is an aerosol?? •

An aerosol is generally de)ned as a suspension of li*uid or solid particles in a gas+ "ith particle diameters in the range of ,-./0,-.1 m 

 The most e%ident e2amples of aerosols in the atmosphere are clouds+ "hich consist primarily of condensed "ater "ith particle diameters on the order of appro2imately ,- mm

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What are the sources of aerosols? •

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Aerosol particles are either emitted directly to the atmosphere 4primary aerosols5 or produced in the atmosphere from precursor gases 4secondary aerosols5 6rimary aerosols consist of both inorganic and organic components 7norganic primary aerosols are relati%ely large and originate from sea spray+ mineral dust+ and %olcanoes 1

Sources and appearance of atmospheric aerosols  Top9 local and large scale air pollution Sources include %olcanic eruptions 4producing %olcanic ash and sulphate5+ sea spray 4sea salt and sulphate aerosols5+ desert storms 4mineral dust5+ sa%annah biomass burning 4:C and OC5+ coal po"er plants 4fossil fuel :C and OC+ sulphate+ nitrate5+ ships 4:C+ OC+ sulphates+ nitrate5+ coo'ing; 4domestic :C and OC5+ road transport 4sulphate+ :C+ 1 µm

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Atmospheric cycling of aerosols

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at ro es o aeroso s play in Earths atmosphere?  They act as cloud condensation nuclei

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 They alter albedo 4both directly and indirectly %ia clouds5 and hence Earths radiation budget  They ser%e as catalysts or sites for atmospheric chemistry reactions /

Three types of aerosols signicantly a!ect the "arth#s climate$