Ch. 20 Air PollutionCh. 20 Air Pollution

Earth’s AtmosphereEarth’s Atmosphereknow the know the

difference!!difference!! Outdoor air pollutionOutdoor air pollution - troposphere - troposphere Global WarmingGlobal Warming

troposphere troposphere stratospherestratosphere

Ozone DepletionOzone Depletion mostly stratospheremostly stratosphere

NaturallyNaturally occurring Pollutants occurring PollutantsVOC’sVOC’s – trees (terpenes & isoprenes), animal waste (aldehydes, – trees (terpenes & isoprenes), animal waste (aldehydes,

methanol, acetone)methanol, acetone)CHCH44 -- metabolic activity in organisms, decaying swamp -- metabolic activity in organisms, decaying swamp

vegetationvegetationSOSO22 -- volcanoes, sea spray, decaying vegetation -- volcanoes, sea spray, decaying vegetationHH22SS – geysers/hot springs, decay in bogs (hydrogen sulfide) – geysers/hot springs, decay in bogs (hydrogen sulfide)ParticulatesParticulates – volcanoes(ash), forest fires (ash), trees (pollen), – volcanoes(ash), forest fires (ash), trees (pollen),

dust storms (dirt)dust storms (dirt)COCO -- forest fires -- forest firesCOCO22 -- respiration of organisms -- respiration of organisms NN22OO -- soil denitrification by bacteria (nitrous oxide) -- soil denitrification by bacteria (nitrous oxide)NOxNOx – decaying organic matter & ammonia in fertilizer – decaying organic matter & ammonia in fertilizerOO33– lightning (in the troposphere)– lightning (in the troposphere)

Air Pollution SourcesAir Pollution SourcesPoint SourcePoint Source -–from a controlled site -–from a controlled site

(smokestacks, vents, etc)(smokestacks, vents, etc)Non-Point SourcesNon-Point Sources – burning leaves, road – burning leaves, road

dust, dust from construction site,dust, dust from construction site, Fugitive SourcesFugitive Sources – open areas exposed to – open areas exposed to

wind processes – dirt roads, construction sites, wind processes – dirt roads, construction sites, farmland, surface mines, etc.farmland, surface mines, etc.

Mobile SourcesMobile Sources – emitters that move from – emitters that move from place to place – autos, trucks, buses, aircraft, place to place – autos, trucks, buses, aircraft, ships, trainsships, trains

Primary Air PollutantsPrimary Air Pollutants : : SO2SO2 NONO NO2NO2 COCO CO2CO2 PM-10PM-10 VOC’s (including hydrocarbons)VOC’s (including hydrocarbons)

AnthropogenicAnthropogenic ( (man-mademan-made) ) sources:sources:

SOSO22 - burning fossil fuels (mostly coal)- burning fossil fuels (mostly coal)NO & NONO & NO22 (NOx) - fossil fuel burning (mostly car (NOx) - fossil fuel burning (mostly car

exhaust)exhaust)CO CO - fossil fuel burning (mostly car exhaust)- fossil fuel burning (mostly car exhaust)

PM-10PM-10 - fly - fly ashash, carbon black (soot), smoke , carbon black (soot), smoke (tobacco, oil), industrial fumes, agricultural (tobacco, oil), industrial fumes, agricultural practices (insecticide/pesticide, plowing)practices (insecticide/pesticide, plowing)

VOC’sVOC’s - industrial processes (solvents, dyes, - industrial processes (solvents, dyes, finishes– ( CFCs and HCs, i.e. benzene)finishes– ( CFCs and HCs, i.e. benzene)

Health Effects of Primary Health Effects of Primary PollutantsPollutants::

lung irritant aggravates lung irritant aggravates (asthma, bronchitis, (asthma, bronchitis, emphysema) -NOx/SOemphysema) -NOx/SO

black lung disease - SPMblack lung disease - SPM carcinogens - VOCscarcinogens - VOCsHeadaches, dizziness - COHeadaches, dizziness - CO

Photochemical/Industrial Photochemical/Industrial SmogSmog

Photochemical SmogPhotochemical SmogYellowish- Brown/NOxYellowish- Brown/NOx fig. 20.5fig. 20.5

VOCs + NOx + heat + sunlight VOCs + NOx + heat + sunlight Ground level O3Ground level O3 brownish hazebrownish haze Irritates respiratory tract Irritates respiratory tract Worse on hot daysWorse on hot days Trees contribute – VOCs isopreneTrees contribute – VOCs isoprene

Industrial SmogIndustrial Smog

Gray smog/SOGray smog/SO22 fig. 20.6fig. 20.6

mixture of SOmixture of SO22 + droplets of + droplets of HH22SOSO4 4 ++ PM-10 - coal (soot)PM-10 - coal (soot)

PM – 10 fine less than 10 PM – 10 fine less than 10 microns microns Worse (ultra fine <2.5)Worse (ultra fine <2.5)Respiratory diseaseRespiratory disease

gray smoggray smog

Factors influencing the Factors influencing the formation of Smog:formation of Smog:

climate climate topography topography population densitypopulation density the amount of industrythe amount of industry

Thermal InversionsThermal Inversionsfig. 20.7fig. 20.7

layer of cool air trapped beneath layer of cool air trapped beneath warm air warm air prevents air currents from dispersing prevents air currents from dispersing

pollutantspollutants WhereWhere

Valley surrounded by mountainsValley surrounded by mountains City – 3 sides mountains, 1 side oceanCity – 3 sides mountains, 1 side ocean

Acid DepositionAcid Depositionfig. 20.8fig. 20.8

Sulfur dioxideSulfur dioxideNitrogen oxidesNitrogen oxidesAcidic rain, snow, fogAcidic rain, snow, fogUS pH 4.4 - 4.8US pH 4.4 - 4.8CaCOCaCO33 (calcium carbonate buffers (calcium carbonate buffers soil)soil)

Effects of Acid DepositionEffects of Acid Deposition:: Reduces visibilityReduces visibility Plants – causes chlorosis,(yellowing of Plants – causes chlorosis,(yellowing of

leaves & needles) - destroy the leaves & needles) - destroy the chlorophyll, inhibit growthchlorophyll, inhibit growth

Leaches nutrients (Ca Leaches nutrients (Ca 2+2+ , Mg , Mg 2+2+ ) from ) from topsoil, plants susceptible to disease/peststopsoil, plants susceptible to disease/pests

Inorganic mercury + acidic water Inorganic mercury + acidic water methyl mercury ,bioaccumulates in fish, methyl mercury ,bioaccumulates in fish, bioaccumulates in these who eat fish bioaccumulates in these who eat fish causing brain damage or neurological causing brain damage or neurological disorders.disorders.

Acidifies lakes and streams killing aquatic life Acidifies lakes and streams killing aquatic life (fish, macroinvertebrates, phytoplankton) when (fish, macroinvertebrates, phytoplankton) when the pH is 4.5 and lessthe pH is 4.5 and less

Dissolves buildings, statues, and bridges that Dissolves buildings, statues, and bridges that contain limestone or marble. (Concrete contains contain limestone or marble. (Concrete contains limestone)limestone)

Promotes acidic moss growth -drowns trees, kill Promotes acidic moss growth -drowns trees, kill mycorrhizal fungi that help roots absorb mycorrhizal fungi that help roots absorb nutrientsnutrients

Slows decomposition of forest floor plant material Slows decomposition of forest floor plant material - acid destroys the microbial decomposers- acid destroys the microbial decomposers

Effects of Acid DepositionEffects of Acid Deposition::

Factors increasing air Factors increasing air pollutionpollution

urban buildings – reduce wind urban buildings – reduce wind speedspeed

Hills/mountains – reduce air Hills/mountains – reduce air flowflow

high temperatures - increase high temperatures - increase secondary air pollutantssecondary air pollutants

Indoor Air PollutantsIndoor Air Pollutants 4 most dangerous 4 most dangerous

Cigarette smokeCigarette smokeFormaldehydeFormaldehydeRadiactive radon-222 gasRadiactive radon-222 gasVery small fine/ultrafine particlesVery small fine/ultrafine particles

Developing countriesDeveloping countriesBurning wood, coal, drop residuesBurning wood, coal, drop residues

Indoor air pollutantIndoor air pollutantfig. 20.13fig. 20.13

AsbestosAsbestos Nitrogen Nitrogen

oxidesoxides TrichloroethanTrichloroethan

ee ChloroformChloroform

Para-dichlorobenzPara-dichlorobenz

tetrachloroethylenetetrachloroethylene FormaldehydeFormaldehyde StyreneStyrene radonradon

Study source and threat

Your respiratory system Your respiratory system protects you! protects you! fig. 20.15fig. 20.15

Nasal hairsNasal hairsUpper respiratory sticky Upper respiratory sticky mucusmucus

Sneezing/coughingSneezing/coughingCilia in air passagesCilia in air passages

PreventionPrevention Clean Air Act – set regulations for key Clean Air Act – set regulations for key

pollutantspollutants NAAQS – national ambient air quality NAAQS – national ambient air quality

standardsstandards HAPS – hazardous air pollutants HAPS – hazardous air pollutants

standardsstandards TRI – toxic release inventoryTRI – toxic release inventory

7 provisions of the 7 provisions of the Clean Air Clean Air ActAct Establish - Establish - NAAQS (National Ambient Air Quality NAAQS (National Ambient Air Quality

Standards) – Standards) – 6 pollutants CO, SO2, NO2, PM-10, Pb, O6 pollutants CO, SO2, NO2, PM-10, Pb, O33 monitor outdoor air on a daily basis monitor outdoor air on a daily basis Prevent air quality deteriorationPrevent air quality deterioration Set national emission standards –toxic industrial Set national emission standards –toxic industrial

emissionsemissions Require coal-burning power plants to cut SORequire coal-burning power plants to cut SO22 emissions emissions Require mobile sources to reduce NORequire mobile sources to reduce NO22 emissions emissions Require oil companies to sell cleaner burning gasolineRequire oil companies to sell cleaner burning gasoline Allow an Emissions Trading Policy (pollution credits) for Allow an Emissions Trading Policy (pollution credits) for

SOSO22

Reducing EmissionsReducing Emissions

Removes particulates & SO2