Air and Air PollutionAir and Air Pollution

Brian Kaestner

Saint Mary’s Hall

Brian Kaestner

Saint Mary’s Hall

Thanks to Miller and ClementsThanks to Miller and Clements

Key ConceptsKey Concepts

Structure and composition of the atmosphere Structure and composition of the atmosphere

Types and sources of outdoor air pollution Types and sources of outdoor air pollution

Types, formation, and effects of smog Types, formation, and effects of smog

Sources and effects of acid deposition Sources and effects of acid deposition

Effects of air pollution Effects of air pollution

Prevention and control of air pollution Prevention and control of air pollution

The AtmosphereThe Atmosphere

Troposphere Troposphere

Stratosphere Stratosphere

78% N, 21% O 78% N, 21% O

Ozone layer Ozone layer

Greenhouse effect Greenhouse effectPressure = 1,000Pressure = 1,000millibars atmillibars atground levelground level

Atmospheric pressure (millibars)Atmospheric pressure (millibars)

00 200200 400400 600600 800800 1,0001,000120120

110110

100100

9090

8080

7070

6060

5050

4040

3030

2020

1010

00(Sea(Sea

Level)Level)

––8080 ––4040 00 4040 8080 120120Temperature (˚C)Temperature (˚C)

Alt

itu

de

(k

ilo

me

ters

)A

ltit

ud

e (

kil

om

ete

rs)

Alt

itu

de

(m

ile

s)

Alt

itu

de

(m

ile

s)

7575

6565

5555

4545

3535

2525

1515

55

ThermosphereThermosphere

Heating via ozoneHeating via ozone

MesosphereMesosphere

StratosphereStratosphere

Ozone “layer”

Heating from the earthTroposphere

TemperatureTemperature

PressurePressure

MesopauseMesopause

StratopauseStratopause

Tropopause

Fig. 17.2, p. 418

Outdoor Air PollutionOutdoor Air Pollution

Primary pollutants Primary pollutants Secondary pollutants Secondary pollutants

Primary Pollutants

Secondary Pollutants

SourcesNatural Stationary

CO CO2

SO2 NO NO2

Most hydrocarbons

Most suspendedparticles

SO3

HNO3 H2SO4

H2O2 O3 PANs

Most and saltsNO3–

Mobile

SO42–

Fig. 17.4, p. 422See Table 17-1 p. 421See Table 17-2 p. 422

Nitric oxide Nitrogen dioxide Ozone40

30

20

10

06 7 8 9 10 11 12 1 2 3 4 5 6 7 8

A.M. Noon P.M.Time

Par

ts p

er m

illi

on

Fig. 17.6, p. 424

Photochemical SmogPhotochemical Smog

Brown-air smog Brown-air smog

Photochemicalreaction

Photochemicalreaction

Photochemicaloxidants

Photochemicaloxidants

Solarradiation

Ultraviolet radiation

NONitric oxide

Photochemical smog

H2OWater

NO2

Nitrogendioxide

Hydrocarbons

O2

Molecularoxygen

HNO3

Nitric acid

PANsPeroxyacyl

nitratesAldehydes

(e.g., formaldehyde)

O3

Ozone

OAtomicoxygen

Fig. 17.5, p. 424

Industrial SmogIndustrial Smog

Gray-air smogGray-air smog

Industrial smogIndustrial smog

Sulfuric acidSulfuric acid

Sulfur dioxideSulfur dioxide

ParticulatesParticulates

Ultra FineUltra FineParticlesParticles

FineFineParticlesParticles

LargeLargeParticlesParticles

Sea salt nuclei

Carbon black

Pollens

Cement dust

Oil smoke

Combustion nuclei

Metallurgical dust and fumes

Photochemical smog

Insecticide dusts

Coal dust

Average particle diameter (micrometers or microns)Average particle diameter (micrometers or microns)0.0010.001 0.010.01 2.52.5 10.010.0 100.0100.0

Tobacco smoke

Paint pigments

Fly ash

Milled flour

Fig. 17.7, p. 425

LA - 1956

Temperature InversionsTemperature Inversions

Subsidence inversionSubsidence inversion

Radiation inversionRadiation inversionWarmer airWarmer air

Inversion layerInversion layer

Cool layer

MountainMountainMountain

ValleyValley

Decreasing temperatureDecreasing temperature

Incr

easi

ng

alt

itu

de

Incr

easi

ng

alt

itu

de

Fig. 17.8, p. 426

Inversion layer

Mountainrange

Sea breeze

Descending warm air mass

Decreasing temperature

Incr

easi

ng

alt

itu

de

Fig. 17.8b, p. 426

Regional Outdoor Air Pollution from Acid DepositionRegional Outdoor Air Pollution from Acid Deposition

Acid depositionAcid depositionWet depositionWet deposition Dry depositionDry deposition

Wind

Transformation tosulfuric acid (H2SO4)and nitric acid (HNO3)

Nitric oxide (NO)

Acid fog

Ocean

Sulfur dioxide (SO2)and NO

Windborne ammonia gasand particles of cultivated soilpartially neutralize acids andform dry sulfate and nitrate salts

Dry aciddeposition(sulfur dioxidegas and particlesof sulfate andnitrate salts)

Farm

Lakes indeep soilhigh in limestoneare buffered

Lakes in shallowsoil low inlimestonebecomeacidic

Wet acid deposition(droplets of H2SO4 andHNO3 dissolved in rainand snow)

Fig. 17.9, p. 428

Acid Deposition in the USAcid Deposition in the US

Fig. 17.10, p. 428

Potential problem areasbecause of sensitive soils

Potential problem areas because of air pollution: emissions leading to acid deposition

Current problem areas(including lakes and rivers) Fig. 17.11, p. 429

Acid Deposition and HumansAcid Deposition and Humans

Respiratory diseases Respiratory diseases

Toxic metal leaching Toxic metal leaching

Decreased visibility Decreased visibility

Damage to structures, especially containing limestone

Damage to structures, especially containing limestone

Decreased productivity and profitability of fisheries, forests, and farms

Decreased productivity and profitability of fisheries, forests, and farms

Acid Deposition and Aquatic SystemsAcid Deposition and Aquatic Systems

Fish declines Fish declines

Undesirable species

Undesirable species

Aluminum toxicity

Aluminum toxicity

Acid shock Acid shock

WaterWaterboatmanboatman

WhirligigWhirligig

Yellow perchYellow perch

Lake troutLake trout

Brown troutBrown trout

SalamanderSalamander(embryonic)(embryonic)

MayflyMayfly

SmallmouthSmallmouthbassbass

MusselMussel

6.56.5 6.06.0 5.55.5 5.05.0 4.54.5 4.04.0 3.53.5pHpH

Fig. 17.13, p. 430

Acid Deposition, Plants, and SoilAcid Deposition, Plants, and Soil

Nutrient leaching

Nutrient leaching

Heavy metal release

Heavy metal release

Weakens trees Weakens trees

Emissions

Effects of Weather

Aciddeposition

Dryweather

Lowprecipitation

Increasedevapotranspiration

Increasedtranspiration

LakeGroundwater

SO2 NOX

H2O2 O3

PANs Others

Increasedsusceptibility

to frost,pests, fungi,

mosses,and disease

Dead leavesor needles

Reducedphotosynthesis

and growth

Tree deathDamageto treecrown

Waterdeficit

Nutrientdeficiency

Bark damage

Direct damageto leaves

and needles

Leaching ofsoil nutrients

Acidsand soilnutrients

Damage tofine roots Disturbance

of wateruptake

Disturbanceof nutrient

uptake

Soil acidification

Kills certainessential soil

microorganisms

Release of toxic metal ionsN

itra

te

Su

lfat

e

Mag

nes

ium

Alu

min

um

Cal

ciu

m

Po

tass

ium

Aci

ds

Fig. 17.14, p. 432See Connections p. 431

Solutions: Preventing and Reducing Air PollutionSolutions: Preventing and Reducing Air Pollution

Clean Air ActClean Air Act

National Ambient Air Quality Standards (NAAQS)

National Ambient Air Quality Standards (NAAQS)

Primary and secondary standardsPrimary and secondary standards

Output control vs. input controlOutput control vs. input control

Emission ReductionEmission Reduction

Prevention Dispersionor Cleanup

Burn low-sulfurcoal

Remove sulfurfrom coal

Convert coalto a liquid orgaseous fuel

Shift to lesspolluting fuels

Disperseemissions abovethermal inversionlayer with tallsmokestacks

Removepollutants aftercombustion

Tax each unitof pollutionproduced

Fig. 17.21, p. 442

Electrostatic Precipitator

Dirty gasDust discharge

ElectrodesCleaned gas

Fig. 17.22, p. 442

Dirty gas

Dirty water

Cleanwater

Wet Scrubber

Wetgas

Cleaned gas

Fig. 17.22d, p. 442

Cyclone Separator

Dirty gas

Dust discharge

Cleaned gas

Fig. 17.22c, p. 442

Cleaned gas

Dirty gas

Baghouse Filter Dust discharge

Bags

Fig. 17.22b, p. 442

Indoor Air Pollution/Sick Building SyndromeIndoor Air Pollution/Sick Building Syndrome

ChloroformPara-dichlorobenzene Tetrachloroethylene

Formaldehyde

Benzo--pyrene

Styrene

Radon-222Methylene Chloride

Tobacco Smoke

Carbon Monoxide

Asbestos

Nitrogen Oxides

1, 1, 1-Trichloroethane

Fig. 17.16, p. 435

RadonRadon

Radon-222 Radon-222

4 picocurie level 4 picocurie level

Occurs in certain areas based on geology

Occurs in certain areas based on geology

Associated with uranium and organic material in rock

Associated with uranium and organic material in rock

Outlet vents for furnaces and dryers

Slab jointsWood stove

Cracks in floorClothes dryerFurnace

Radon-222 gas

Slab

Radium-222

Soil

Uranium-238

Sumppump

Cracks in wallCracks in wall

Open windowOpen window

Openingsaroundpipes

Openingsaroundpipes

Fig. 17.17, p. 436

Reducing IndoorAir PollutionReducing IndoorAir Pollution

Prevention Cleanup orDilutionCover ceiling

tiles and liningof AC ducts toprevent releaseof mineral fibers

Ban smoking orlimit it to well-ventilated areas

Set stricterformaldehydeemissionsstandards forcarpet,furniture,and buildingmaterials

Prevent radoninfiltration

Use officemachines inwell-ventilatedareas

Use lesspollutingsubstitutes forharmfulcleaningagents, paints, and other products

Use adjustablefresh air ventsfor work spaces

Increase intakeof outside air

Change airmore frequently

Circulate building’s airthrough rooftopgreenhouses

Use exhausthoods for stoves andappliances burning naturalgas

Install efficientchimneys forwood-burningstoves

Fig. 17.24, p. 443