chapter 19 air pollution. when is a lichen like a canary? lichens can warn us of bad air because...

Chapter 19Chapter 19

Air PollutionAir Pollution

When Is a Lichen Like a Canary?When Is a Lichen Like a Canary?

Lichens can warn Lichens can warn us of bad air us of bad air because they because they absorb it as a absorb it as a source of source of nourishment.nourishment.

When Is a Lichen Like a Canary?When Is a Lichen Like a Canary?

Some lichen species are sensitive to specific Some lichen species are sensitive to specific air-polluting chemicals.air-polluting chemicals.

After Chernobyl, more than 70,000 reindeer After Chernobyl, more than 70,000 reindeer had to be killed because they ate highly had to be killed because they ate highly radioactive lichens.radioactive lichens.

Because lichens are widespread, long-lived, Because lichens are widespread, long-lived, and anchored in place, they can help track and anchored in place, they can help track pollution to its source.pollution to its source.

STRUCTURE AND SCIENCE OF STRUCTURE AND SCIENCE OF THE ATMOSPHERETHE ATMOSPHERE

The atmosphere The atmosphere consists of several consists of several layers with different layers with different temperatures, temperatures, pressures, and pressures, and compositions.compositions.

Fig. 19-2, p. 440

Atmospheric pressure (millibars)

Temperature

Thermosphere

Pressure

Mesopause

Heating via ozoneMesosphere

Stratopause

Alt

itu

de

(kil

om

eter

s)

Stratosphere Alt

itu

de

(mil

es)

Tropopause

Ozone “layer”

Heating from the earthHeating from the earthTroposphere

Temperature (˚C)

Pressure = 1,000 millibars at ground level

(Sea level)

STRUCTURE AND SCIENCE OF STRUCTURE AND SCIENCE OF THE ATMOSPHERETHE ATMOSPHERE

The atmosphere’s innermost layer The atmosphere’s innermost layer (troposphere) is made up mostly of nitrogen (troposphere) is made up mostly of nitrogen and oxygen, with smaller amounts of water and oxygen, with smaller amounts of water vapor and COvapor and CO22..

Ozone in the atmosphere’s second layer Ozone in the atmosphere’s second layer (stratosphere) filters out most of the sun’s (stratosphere) filters out most of the sun’s UV radiation that is harmful to us and most UV radiation that is harmful to us and most other species.other species.

AIR POLLUTIONAIR POLLUTION

Some primary air pollutants may react with one Some primary air pollutants may react with one another or with other chemicals in the air to form another or with other chemicals in the air to form secondary air pollutants.secondary air pollutants.

Primary Pollutants

CO CO2Secondary Pollutants

SO2 NO NO2

Most hydrocarbons SO3

Most suspended particles HNO3

H2O2 O3 PANs

Most NO3– and SO4

2– salts

Sources Natural Stationary

Mobile

H3SO4

Major Air PollutantsMajor Air Pollutants

Carbon oxidesCarbon oxides: : Carbon monoxide (CO) is a highly toxic gas that Carbon monoxide (CO) is a highly toxic gas that

forms during the incomplete combustion of forms during the incomplete combustion of carbon-containing materials.carbon-containing materials.

93% of carbon dioxide (CO93% of carbon dioxide (CO22) in the troposphere ) in the troposphere

occurs as a result of the carbon cycle.occurs as a result of the carbon cycle. 7% of CO7% of CO22 in the troposphere occurs as a result in the troposphere occurs as a result

of human activities (mostly burning fossil fuels).of human activities (mostly burning fossil fuels).• It is not regulated as a pollutant under the U.S. Clean It is not regulated as a pollutant under the U.S. Clean

Air ActAir Act..


Nitrogen oxides Nitrogen oxides andand nitric acid nitric acid: : Nitrogen oxide (NO) forms when nitrogen and Nitrogen oxide (NO) forms when nitrogen and

oxygen gas in air react at the high-combustion oxygen gas in air react at the high-combustion temperatures in automobile engines and coal-temperatures in automobile engines and coal-burning plants. NO can also form from lightening burning plants. NO can also form from lightening and certain soil bacteria.and certain soil bacteria.• NO reacts with air to form NONO reacts with air to form NO22..

• NONO2 2 reacts with water vapor in the air to form nitric acid reacts with water vapor in the air to form nitric acid

(HNO(HNO33) and nitrate salts (NO) and nitrate salts (NO33--) which are components ) which are components

of acid deposition.of acid deposition.


Sulfur dioxide (SOSulfur dioxide (SO22)) andand sulfuric acidsulfuric acid:: About one-third of SOAbout one-third of SO22 in the troposphere occurs in the troposphere occurs

naturally through the sulfur cycle.naturally through the sulfur cycle. Two-thirds come from human sources, mostly Two-thirds come from human sources, mostly

combustion (S+ Ocombustion (S+ O22 SO SO22) of sulfur-containing ) of sulfur-containing

coal and from oil refining and smelting of sulfide coal and from oil refining and smelting of sulfide ores. ores.

SOSO2 2 in the atmosphere can be converted to in the atmosphere can be converted to

sulfuric acid (Hsulfuric acid (H22SOSO44) and sulfate salts (SO) and sulfate salts (SO442-2-) that ) that

return to earth as a component of acid return to earth as a component of acid deposition.deposition.


Suspended particulate matter (SPM)Suspended particulate matter (SPM):: Consists of a variety of solid particles and liquid Consists of a variety of solid particles and liquid

droplets small and light enough to remain droplets small and light enough to remain suspended in the air.suspended in the air.

The most harmful forms of SPM are fine particles The most harmful forms of SPM are fine particles (PM-10, with an average diameter < 10 (PM-10, with an average diameter < 10 micrometers) and ultrafine particles (PM-2.5).micrometers) and ultrafine particles (PM-2.5).

According to the EPA, SPM is responsible for According to the EPA, SPM is responsible for about 60,000 premature deaths a year in the about 60,000 premature deaths a year in the U.S.U.S.


Ozone (OOzone (O33)):: Is a highly reactive gas that is a major Is a highly reactive gas that is a major

component of photochemical smog.component of photochemical smog. It can It can

• Cause and aggravate respiratory illness.Cause and aggravate respiratory illness.• Can aggravate heart disease.Can aggravate heart disease.• Damage plants, rubber in tires, fabrics, and paints. Damage plants, rubber in tires, fabrics, and paints.


Volatile organic compounds (VOCs)Volatile organic compounds (VOCs):: Most are hydorcarbons emitted by the leaves of Most are hydorcarbons emitted by the leaves of

many plants and methane.many plants and methane. About two thirds of global methane emissions About two thirds of global methane emissions

comes from human sources.comes from human sources. Other VOCs include industrial solvents such as Other VOCs include industrial solvents such as

trichlorethylene (TCE), benzene, and vinyl trichlorethylene (TCE), benzene, and vinyl chloride.chloride.• Long-term exposure to benzene can cause cancer, Long-term exposure to benzene can cause cancer,

blood disorders, and immune system damage.blood disorders, and immune system damage.


Radon (Rn)Radon (Rn):: Is a naturally occurring radioactive gas found in Is a naturally occurring radioactive gas found in

some types of soil and rock.some types of soil and rock. It can seep into homes and buildings sitting It can seep into homes and buildings sitting

above such deposits.above such deposits.

URBAN OUTDOOR AIR POLLUTIONURBAN OUTDOOR AIR POLLUTION

Industrial smog is a mixture of sulfur dioxide, Industrial smog is a mixture of sulfur dioxide, droplets of sulfuric acid, and a variety of droplets of sulfuric acid, and a variety of suspended solid particles emitted mostly by suspended solid particles emitted mostly by burning coal.burning coal. In most developed countries where coal and In most developed countries where coal and

heavy oil is burned, industrial smog is not a heavy oil is burned, industrial smog is not a problem due to reasonably good pollution control problem due to reasonably good pollution control or with tall smokestacks that transfer the pollutant or with tall smokestacks that transfer the pollutant to rural areas.to rural areas.

South Asia’s Massive Brown CloudSouth Asia’s Massive Brown Cloud

A huge dark brown cloud of industrial smog, A huge dark brown cloud of industrial smog, caused by coal-burning in countries such as caused by coal-burning in countries such as China and India, stretches over much of China and India, stretches over much of southeastern Asia.southeastern Asia. In areas beneath the cloud, photosynthesis is In areas beneath the cloud, photosynthesis is

reduced interfering with crop development.reduced interfering with crop development. Fine particles and droplets in the cloud appear to Fine particles and droplets in the cloud appear to

be changing regional climates (including rainfall).be changing regional climates (including rainfall).• May have contributed to floods in 2002 and 2005 May have contributed to floods in 2002 and 2005

which killed thousands of people.which killed thousands of people.

Sunlight plus Cars Equals Sunlight plus Cars Equals Photochemical SmogPhotochemical Smog

Photochemical smog is a mixture of air Photochemical smog is a mixture of air pollutants formed by the reaction of nitrogen pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbons oxides and volatile organic hydrocarbons under the influence of sunlight.under the influence of sunlight.

Sunlight plus Cars Equals Sunlight plus Cars Equals Photochemical SmogPhotochemical Smog

Mexico City is one Mexico City is one of the many cities of the many cities in sunny, warm, dry in sunny, warm, dry climates with many climates with many motor vehicles that motor vehicles that suffer from suffer from photochemical photochemical smog.smog.

Formation of Photochemical SmogFormation of Photochemical Smog

PLAYANIMATION

Factors Influencing Levels of Factors Influencing Levels of Outdoor Air PollutionOutdoor Air Pollution

Outdoor air pollution can be reduced by:Outdoor air pollution can be reduced by: settling out, precipitation, sea spray, winds, and settling out, precipitation, sea spray, winds, and

chemical reactions. chemical reactions. Outdoor air pollution can be increased by:Outdoor air pollution can be increased by:

urban buildings (slow wind dispersal of urban buildings (slow wind dispersal of pollutants), mountains (promote temperature pollutants), mountains (promote temperature inversions), and high temperatures (promote inversions), and high temperatures (promote photochemical reactions).photochemical reactions).

Temperature InversionsTemperature Inversions

Cold, cloudy weather in a valley surrounded Cold, cloudy weather in a valley surrounded by mountains can trap air pollutants (left).by mountains can trap air pollutants (left).

Areas with sunny climate, light winds, Areas with sunny climate, light winds, mountains on three sides and an ocean on mountains on three sides and an ocean on the other (right) are susceptible to inversions.the other (right) are susceptible to inversions.

Warmer air Descending warm air mass

Inversion layer Inversion layer

Sea breezeIncreasing altitude

Decreasing temperature

Animation: Thermal Invasion and SmogAnimation: Thermal Invasion and Smog

PLAYANIMATION

ACID DEPOSITIONACID DEPOSITION

Sulfur dioxides, nitrogen oxides, and Sulfur dioxides, nitrogen oxides, and particulates can react in the atmosphere to particulates can react in the atmosphere to produce acidic chemicals that can travel long produce acidic chemicals that can travel long distances before returning to the earth’s distances before returning to the earth’s surface.surface. Tall smokestacks reduce local air pollution but Tall smokestacks reduce local air pollution but

can increase regional air pollution.can increase regional air pollution.

Animation: Acid DepositionAnimation: Acid Deposition

PLAYANIMATION


Acid deposition consists of rain, snow, dust, Acid deposition consists of rain, snow, dust, or gas with a pH lower than 5.6.or gas with a pH lower than 5.6.

WindTransformation to sulfuric acid (H2SO4) and nitric acid (HNO3)

Windborne ammonia gas and particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts

Wet acid depostion (droplets of H2SO4 and HNO3 dissolved in rain and snow)

Nitric oxide (NO)Sulfur dioxide (SO2) and NO

Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts)

Acid fogFarm

OceanLakes in deep Lakes in deep

soil high in soil high in limestone are limestone are

bufferedbuffered

Lakes in shallow Lakes in shallow soil low in limestone soil low in limestone

become acidicbecome acidic


pH measurements in relation to major coal-pH measurements in relation to major coal-burning and industrial plants.burning and industrial plants.


Acid deposition contributes to chronic Acid deposition contributes to chronic respiratory disease and can leach toxic respiratory disease and can leach toxic metals (such as lead and mercury) from soils metals (such as lead and mercury) from soils and rocks into acidic lakes used as sources and rocks into acidic lakes used as sources for drinking water.for drinking water.


Air pollution is Air pollution is one of several one of several interacting interacting stresses that can stresses that can damage, damage, weaken, or kill weaken, or kill trees and pollute trees and pollute surface and surface and groundwater.groundwater.

Emissions

SO2 NOxAcid deposition

H2O2 O3

Others

Direct damage to leaves & bark

Reduced photo-synthesis and growth

Susceptibility to drought, extreme cold, insects, mosses, & disease organisms

Soil acidification

Tree death

Leaching

of soil nutrients

Release of toxic metal ions

Root damage

Reduced nutrient & water uptakeAcids

Lake

Groundwater

PANs

Animation: Effects of Air Pollution in Animation: Effects of Air Pollution in ForestsForests

PLAYANIMATION

Solutions

Acid Deposition

Prevention Cleanup

Reduce air pollution by improving energy efficiency

Add lime to neutralize acidified lakes

Reduce coal use

Add phosphate fertilizer to neutralize acidified lakes

Increase natural gas use

Increase use of renewable energy resources

Burn low-sulfur coal

Remove SO2 particulates & NOx from smokestack gases

Remove NOx from motor vehicular exhaust

Tax emissions of SO2

INDOOR AIR POLLUTIONINDOOR AIR POLLUTION

Indoor air pollution usually is a greater threat Indoor air pollution usually is a greater threat to human health than outdoor air pollution.to human health than outdoor air pollution.

According to the EPA, the four most According to the EPA, the four most dangerous indoor air pollutants in developed dangerous indoor air pollutants in developed countries are:countries are: Tobacco smoke.Tobacco smoke. Formaldehyde.Formaldehyde. Radioactive radon-222 gas.Radioactive radon-222 gas. Very small fine and ultrafine particles.Very small fine and ultrafine particles.

Chloroform

Benzo--pyrene

Styrene

Radon-222

Methylene Chloride

Tobacco Smoke

Carbon Monoxide

Asbestos

Nitrogen Oxides

1, 1, 1-Trichloroethane

Particulates

FormaldehydeTetrachloroethylene

Para-dichlorobenzene

INDOOR AIR POLLUTIONINDOOR AIR POLLUTION

Household dust mites Household dust mites that feed on human skin that feed on human skin and dust, live in and dust, live in materials such as materials such as bedding and furniture bedding and furniture fabrics.fabrics. Can cause asthma Can cause asthma

attacks and allergic attacks and allergic reactions in some reactions in some people.people.

Case Study: Radioactive RadonCase Study: Radioactive Radon

Radon-222, a Radon-222, a radioactive gas radioactive gas found in some found in some soils and rocks, soils and rocks, can seep into can seep into some houses and some houses and increase the risk increase the risk of lung cancer.of lung cancer.

Sources and paths of entry Sources and paths of entry for indoor radon-222 gasfor indoor radon-222 gas.

Outlet vents for furnaces and dryers

Open window

Openings around pipes

Cracks in wall

Slab joints

Wood stove

Cracks in floorClothes

dryerSump Sump pumppumpFurnace

Slab Radon-222 gas Uranium-238

Soil

HEALTH EFFECTS OF AIR HEALTH EFFECTS OF AIR POLLUTIONPOLLUTION

Your respiratory system can help protect you Your respiratory system can help protect you from air pollution, but some air pollutants can from air pollution, but some air pollutants can overcome these defenses.overcome these defenses.

Epithelial cellCilia

Nasal cavity

Oral cavity

Goblet cell (secreting mucus)

Pharynx (throat)

MucusTrachea (windpipe)

BronchusBronchioles

Right lung

Bronchioles

Alveolar sac (sectioned)

Alveoli

Alveolar duct

HEALTH EFFECTS OF AIR HEALTH EFFECTS OF AIR POLLUTIONPOLLUTION

Normal human lungs (left) and the lungs of a Normal human lungs (left) and the lungs of a person who died of emphysema (right).person who died of emphysema (right).

Air Pollution is a Big KillerAir Pollution is a Big Killer

Each year, air pollution prematurely kills Each year, air pollution prematurely kills about 3 million people, mostly from indoor air about 3 million people, mostly from indoor air pollution in developing countries.pollution in developing countries. In the U.S., the EPA estimates that annual deaths In the U.S., the EPA estimates that annual deaths

related to indoor and outdoor air pollution range related to indoor and outdoor air pollution range from 150,000 to 350,000.from 150,000 to 350,000.

According to the EPA, each year more than According to the EPA, each year more than 125,000 Americans get cancer from breathing 125,000 Americans get cancer from breathing diesel fumes.diesel fumes.

Air Pollution is a Big KillerAir Pollution is a Big Killer

Spatial distribution of premature deaths from Spatial distribution of premature deaths from air pollution in the United States.air pollution in the United States.

PREVENTING AND REDUCING AIR PREVENTING AND REDUCING AIR POLLUTIONPOLLUTION

The Clean Air Acts in the United States have The Clean Air Acts in the United States have greatly reduced outdoor air pollution from six greatly reduced outdoor air pollution from six major pollutants:major pollutants: Carbon monoxideCarbon monoxide Nitrogen oxidesNitrogen oxides Sulfur dioxidesSulfur dioxides Suspended particulate matter (less than PM-10)Suspended particulate matter (less than PM-10)


Environmental scientists point out several Environmental scientists point out several deficiencies in the Clean Air Act:deficiencies in the Clean Air Act: The U.S. continues to rely on cleanup rather than The U.S. continues to rely on cleanup rather than

prevention.prevention. The U.S. Congress has failed to increase fuel-The U.S. Congress has failed to increase fuel-

efficiency standards for automobiles.efficiency standards for automobiles. Regulation of emissions from motorcycles and Regulation of emissions from motorcycles and

two-cycle engines remains inadequate.two-cycle engines remains inadequate. There is little or no regulation of air pollution from There is little or no regulation of air pollution from

oceangoing ships in American ports.oceangoing ships in American ports.


Airports are exempt from many air pollution Airports are exempt from many air pollution regulations.regulations.

The Act does not regulate the greenhouse gas The Act does not regulate the greenhouse gas COCO22..

The Act has failed to deal seriously with indoor air The Act has failed to deal seriously with indoor air pollution.pollution.

There is a need for better enforcement of the There is a need for better enforcement of the Clean Air Act.Clean Air Act.


Executives of companies claim that Executives of companies claim that correcting these deficiencies would cost too correcting these deficiencies would cost too much, harm economic growth, and cost jobs.much, harm economic growth, and cost jobs.

Using the Marketplace to Reduce Using the Marketplace to Reduce Outdoor Air PollutionOutdoor Air Pollution

To help reduce SOTo help reduce SO22 emissions, the Clean Air emissions, the Clean Air

Act authorized and emission trading (cap-Act authorized and emission trading (cap-and-trade) program.and-trade) program. Enables the 110 most polluting power plants to Enables the 110 most polluting power plants to

buy and sell SObuy and sell SO22 pollution rights. pollution rights. Between 1990-2002, the emission trading system Between 1990-2002, the emission trading system

reduced emissions.reduced emissions. In 2002, the EPA reported the cap-and-trade In 2002, the EPA reported the cap-and-trade

system produced less emission reductions than system produced less emission reductions than were projected.were projected.

Video: Clean Air ActVideo: Clean Air Act

PLAYVIDEO

Solutions: Solutions: Reducing Outdoor Air PollutionReducing Outdoor Air Pollution

There are a of ways to prevent and control air There are a of ways to prevent and control air pollution from coal-burning facilities.pollution from coal-burning facilities. Electrostatic precipitatorElectrostatic precipitator: are used to attract : are used to attract

negatively charged particles in a smokestack into negatively charged particles in a smokestack into a collector.a collector.

Wet scrubberWet scrubber: fine mists of water vapor trap : fine mists of water vapor trap particulates and convert them to a sludge that is particulates and convert them to a sludge that is collected and disposed of usually in a landfill.collected and disposed of usually in a landfill.

Electrostatic PrecipitatorElectrostatic Precipitator Can remove 99% of Can remove 99% of

particulate matterparticulate matter Does not remove Does not remove

hazardous ultrafine hazardous ultrafine particles.particles.

Produces toxic dust Produces toxic dust that must be safely that must be safely disposed of.disposed of.

Uses large amounts Uses large amounts of electricityof electricity

Clean gas out

Negatively charged electrode

Positively charged precipitator wall

Dirty gas (smoke) in

Dust falls off into collector

Taken to landfill

Wet ScrubberWet Scrubber

Can remove 98% of Can remove 98% of SOSO22 and particulate and particulate

matter.matter. Not very effective in Not very effective in

removing hazardous removing hazardous fine and ultrafine fine and ultrafine particles.particles.

Clean gas out

Separator

Liquid water in

Dirty gas (smoke) in

Polluted liquid (sludge) out

Solutions

Stationary Source Air Pollution

Prevention

Burn low-sulfur coal

Disperse emissions above thermal inversion layer with tall smokestacks

Remove sulfur from coal

Convert coal to a liquid or gaseous fuel

Remove pollutants after combustion

Shift to less polluting fuels

Tax each unit of pollution produced

Dispersion or Cleanup

Solutions: Solutions: Reducing Outdoor Air PollutionReducing Outdoor Air Pollution

In 2003, fourteen states and a number of In 2003, fourteen states and a number of U.S. cities sued the EPA to block new rules U.S. cities sued the EPA to block new rules that would allow older coal-burning power that would allow older coal-burning power plants to modernize without having to install plants to modernize without having to install the most advanced air pollution controls.the most advanced air pollution controls.

Video: Air Pollution in ChinaVideo: Air Pollution in China

PLAYVIDEO

Solutions

Motor Vehicle Air Pollution

Prevention Cleanup

Emission control devices

Mass transit

Bicycles and walking

Less polluting engines

Less polluting fuels

Improve fuel efficiency

Car exhaust inspections twice a year

Get older, polluting cars off the road

Give buyers large tax write-offs or rebates for buying low-polluting, energy efficient vehicles

Stricter emission standards

Indoor Air PollutionIndoor Air Pollution

Little effort has been devoted to reducing Little effort has been devoted to reducing indoor air pollution even though it poses a indoor air pollution even though it poses a much greater threat to human health than much greater threat to human health than outdoor air pollution.outdoor air pollution.

Environmental and health scientists call for Environmental and health scientists call for us to focus on preventing air pollution us to focus on preventing air pollution (especially indoor) in developing countries.(especially indoor) in developing countries.

Solutions

Indoor Air Pollution

Prevention

Cover ceiling tiles & lining of AC ducts to prevent release of mineral fibers

Use adjustable fresh air vents for work spaces

Increase intake of outside airBan smoking or limit it to well ventilated areas

Change air more frequently

Set stricter formaldehyde emissions standards for carpet, furniture, and building materials

Circulate a building’s air through rooftop green houses

Prevent radon infiltration Use exhaust hoods for stoves and appliances burning natural gasUse office machines in well

ventilated areas

Use less polluting substitutes for harmful cleaning agents, paints, and other products

Install efficient chimneys for wood-burning stoves

Cleanup or Dilution

What Can You Do?

Indoor Air Pollution

• Test for radon and formaldehyde inside your home and take corrective measures as needed.

• Do not buy furniture and other products containing formaldehyde.

• Remove your shoes before entering your house to reduce inputs of dust, lead, and pesticides.

• Test your house or workplace for asbestos fiber levels and for any crumbling asbestos materials if it was built before 1980.

• Don't live in a pre-1980 house without having its indoor air tested for asbestos and lead.

• Do not store gasoline, solvents, or other volatile hazardous chemicals inside a home or attached garage.

• If you smoke, do it outside or in a closed room vented to the outside.

• Make sure that wood-burning stoves, fireplaces, and kerosene- and gas-burning heaters are properly installed, vented, and maintained.

• Install carbon monoxide detectors in all sleeping areas.

Solutions

Air Pollution

Outdoor Indoor

Improve energy efficiency to reduce fossil fuel use

Reduce poverty

Rely more on lower-polluting natural gas

Distribute cheap & efficient cookstoves or solar cookers to poor families in developing countries

Rely more on renewable energy (especially solar cells, wind, & solar-produced hydrogen) Reduce or ban indoor

smoking

Transfer technologies for latest energy efficiency, renewable energy, & pollution prevention to developing countries

Develop simple and cheap tests for indoor pollutants such as particulates, radon, and formaldehyde

chapter 19 air pollution. when is a lichen like a canary? lichens can warn us of bad air because...

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