LIVING IN THE ENVIRONMENT, 18e - TVHS APES - Home

© Cengage Learning 2015

LIVING IN THE ENVIRONMENT, 18e G. TYLER MILLER • SCOTT E. SPOOLMAN


18 Air Pollution


• The South Asian Brown Clouds – Stretch across much of India, Bangladesh,

China, and the western Pacific Ocean • Air pollution connects the world

– Pollutants can circle the globe in about two weeks

• Stricter air pollution standards and continued shifts towards cleaner fuels are needed

Core Case Study: South Asia’s Massive Brown Clouds


The South Asia's Brown Clouds (cont'd.)

Fig. 18-1a, p. 474

Presenter

Presentation Notes

Figure 18.1: The South Asian Brown Clouds are gigantic clouds of dust, smoke, soot, and other pollutants that stretch over much of South Asia. One is visible here over eastern China.


• The two innermost layers of the atmosphere – Troposphere – supports life – Stratosphere – contains the protective ozone

layer

18-1: What is the Nature of the Atmosphere?


• Atmosphere – thin blanket of gases surrounding the Earth

• Density – number of gas molecules per unit of air volume – Density decreases as you move higher in the

atmosphere

The Atmosphere Consists of Several Layers


Fig. 18-2, p. 475

Atmospheric pressure (millibars)

Temperature

Thermosphere

Mesosphere

Altit

ude

(mile

s)

Altit

ude

(kilo

met

ers)

Stratosphere

Ozone layer

Pressure Troposphere

(Sea level) Pressure = 1,000 millibars

at ground level Temperature (˚C)

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Presentation Notes

Figure 18.2: Natural capital. The earth’s atmosphere is a dynamic system that includes four layers. The average temperature of the atmosphere varies with altitude (red line) and with differences in the absorption of incoming solar energy. Question: Why do you think most of the planet’s air is in the troposphere?


• Troposphere – 75–80% of Earth’s air mass – Closest to Earth's surface – Composition of gases

• 78% nitrogen; 21% oxygen

– Rising and falling air currents and greenhouse gases play a major role in weather and climate

Air Movements in the Troposphere Play a Key Role in Earth’s Weather and Climate


• Stratosphere – Similar composition to the troposphere except

that it contains: • Much less water • Ozone layer (O3)

– Filters 95% of harmful UV radiation – Allows life to exist on land

The Stratosphere Is Our Global Sunscreen


• Pollutants mix in the air to form industrial smog – Primarily as a result of burning coal and

photochemical smog – Caused by emissions from motor vehicles,

industrial facilities, and power plants

18-2: What Are the Major Outdoor Pollution Problems?


• Air pollution – presence of chemicals in the atmosphere – Concentrations high enough to harm

organisms, ecosystems, human-made materials, and to alter climate

• Natural sources – Dust blown by wind – Pollutants from wildfires and volcanoes – Volatile organics released by plants

Air Pollution Comes from Natural and Human Sources


• Human sources – Mostly in industrialized and/or urban areas – Stationary sources – power plants and

industrial facilities – Mobile sources – motor vehicles

Air Pollution Comes from Natural and Human Sources (cont’d.)


• Primary pollutants – Emitted directly into the air

• Secondary pollutants – From reactions of primary pollutants

Some Pollutants in the Atmosphere Combine to Form Other Pollutants


Sources and Types of Air Pollutants

Fig. 18-3, p. 477

Primary Pollutants CO CO2 Secondary Pollutants

SO2 NO NO2 CH4 and most

other hydrocarbons SO3

Most suspended particles H2O2 H2SO4

PANs Most NO3

– and SO42– salts

Natural Source Stationary Human Source

Human Source

Mobile

N2O

O3

HNO3

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Presentation Notes

Figure 18.3: Human inputs of air pollutants come from mobile sources (such as cars) and stationary sources (such as industrial, power, and cement plants). Some primary air pollutants react with one another and with other chemicals in the air to form secondary air pollutants.


• Carbon oxides – Carbon monoxide (CO); carbon dioxide (CO2)

• Nitrogen oxides (NO) and nitric acid (HNO3) – Acid deposition; photochemical smog

What Are the Major Outdoor Air Pollutants?

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Presentation Notes

Critical Thinking Question: Science Focus 18.1


• Sulfur dioxide (SO2) and sulfuric acid (H2SO4)

• Particulates – Suspended particulate matter

• Ozone • Volatile organic compounds (VOCs)

– Methane

What Are the Major Outdoor Air Pollutants? (cont’d.)

Chemical Reactions That Form Major Outdoor Air Pollutants

Table 18-1, p. 480

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Presentation Notes

Table 18-1: Chemical Reaction That Form Major Outdoor Air Pollutants


• Chemical composition of industrial smog – Sulfur dioxide, sulfuric acid, and suspended

solid particles • Formed from the burning of fossil fuels

– Carbon monoxide, carbon dioxide, and soot result

• How are pollutants formed from burning coal and oil?

Burning Coal Produces Industrial Smog


Burning coal and oil

Oxygen (O2)

Stepped Art

Ammonium sulfate [(NH4)2SO4]

Ammonia (NH3)

Sulfuric acid (H2SO4)

Water vapor (H2O)

Sulfur trioxide (SO 3 )

Oxygen (O2)

Sulfur dioxide (SO2)

Sulfur (S) in coal and oil

Carbon monoxide (CO) and

carbon dioxide (CO2)

Carbon (C) in coal and oil

Fig. 18-8, p. 481

Presenter

Presentation Notes

Note: This is a carry-over animation from 17e. No modifications have been made to the animation itself; we have simply updating the figure number and page number in the lower-right corner. Figure 18.8: This is a greatly simplified model of how pollutants are formed when coal and oil are burned. The result is industrial smog.


• Photochemical smog • VOCs + NOx + Heat + Sunlight yields:

– Ground level O3 and other photochemical oxidants

– Aldehydes – Other secondary pollutants

Sunlight Plus Cars Equals Photochemical Smog


PANS and other pollutants Volatile organic compounds (VOCs)

Ozone (O3) Oxygen (O2)

Nitric oxide (NO) + Oxygen atom (O)

Water vapor (H2O) Hydrocarbons UV radiation Peroxyacyl nitrates (PANs) Nitrogen dioxide (NO2)

Oxygen (O2) Nitric oxide (NO)

Oxygen (O2) Burning fossil fuels

Nitrogen (N) in fossil fuel

Fig. 18-9, p. 483

Photochemical Smog

Presenter

Presentation Notes

Figure 18.9: A greatly simplified model of how the pollutants that make up photochemical smog are formed.


• Outdoor air pollution may be decreased by: – Settling of particles due to gravity – Rain and snow – Salty sea spray from the ocean – Winds – Chemical reactions

Several Factors Can Decrease or Increase Outdoor Air Pollution


• Outdoor air pollution may be increased by: – Urban buildings – Hills and mountains – High temperatures – Emissions of VOCs from certain trees and

plants – The grasshopper effect – Temperature inversions

• Warm air above cool air prevents mixing

Several Factors Can Decrease or Increase Outdoor Air Pollution (cont’d.)


A Temperature Inversion

Fig. 18-11, p. 484

Warmer air

Increasing altitude

Decreasing temperature

Sea breeze

Inversion layer Inversion layer

Descending warm air mass

Presenter

Presentation Notes

Figure 18.11: A temperature inversion, in which a warm air layer sits atop a cooler air layer, can take place in either of the two sets of topography and weather conditions shown here. Normally, the air temperature decreases steadily with increasing altitude within the troposphere, but during an inversion, there is a layer of air that is warmer than the cooler air above and below (see graph).


• Caused mainly by coal-burning power plants and motor vehicle emissions

• Threatens human health, aquatic life and ecosystems, forests, and human-built structures in some regions

18-3: What Is Acid Deposition and Why Is It a Problem?


• Acid deposition – Sulfuric acid and nitric acid compounds – Wet deposition – rain, snow, fog, cloud vapor – Dry deposition – particles

• Substances remain in the atmosphere 2-14 days

• What are some ways in which your daily activities contribute to acid deposition?

Acid Disposition Is a Serious Regional Air Pollution Problem


Natural Capital Degradation: Acid Deposition

Fig. 18-12, p. 485

Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas

and some soil particles partially neutralize acids and form dry sulfate and nitrate salts Wet acid deposition

(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 fog

Lakes in deep soil high in limestone are buffered

Lakes in shallow soil low in limestone become acidic

Wind

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Presentation Notes

Figure 18.12: Natural capital degradation. Acid deposition, which consists of rain, snow, dust, or gas with a pH lower than 5.6, is commonly called acid rain. Soils and lakes vary in their ability to neutralize excess acidity.


Current and Possible Future Acid Rain Problem Areas

Fig. 18-13, p. 486

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Presentation Notes

Figure 18.13: This map shows regions where acid deposition is now a problem and regions with the potential to develop this problem. Such regions have large inputs of air pollution (mostly from power plants, industrial facilities, and ore smelters) or are sensitive areas with naturally acidic soils and bedrock that cannot neutralize (buffer) additional inputs of acidic compounds. Question: Do you live in or near an area that is affected by acid deposition or an area that is likely to be affected by acid deposition in the future? (Data from World Resources Institute and U.S. Environmental Protection Agency)


• Human health – Respiratory disorders; toxins from fish

• Release of toxic metals • Aquatic ecosystems

– Lowers pH and kills organisms • Leaching of soil nutrients • Forest damage • Damage to buildings, etc.

Acid Deposition Has a Number of Harmful Effects


Fig. 18-15, p. 488

Solutions Acid Deposition

Prevention Cleanup

Reduce coal use and burn only low-sulfur coal

Add lime to neutralize acidified lakes

Use natural gas and renewable energy resources in place of coal

Add phosphate fertilizer to neutralize acidified lakes Remove SO2 and NOx

from smokestack gases and remove NOx from motor vehicular exhaust

Tax SO2 emissions

Add lime to neutralize acidified soils

Presenter

Presentation Notes

Figure 18-15: There are several ways to reduce acid deposition and the damage. Questions: Which two of these solutions are the best ones? Why?


• The most threatening indoor air pollutants: – Smoke and soot from the burning of wood

and coal in cooking fires (mostly in less-developed countries)

– Cigarette smoke – Chemicals used in building materials and

cleaning products

18-4: What Are the Major Indoor Air Pollution Problems?


• In developing countries – Indoor burning of wood, charcoal, dung, crop

residues, coal – Greatest risk to low-income populations

• In developed countries – Indoor air pollution is greater than outdoor air

pollution – Chemicals used in building materials

Indoor Air Pollution Is a Serious Problem

Fig. 18-17, p. 489

Chloroform Source: Chlorine-treated water in hot showers Possible threat: Cancer

Para-dichlorobenzene Source: Air fresheners, mothball crystals Threat: Cancer

Tetrachloroethylene Source: Dry-cleaning fluid fumes on clothes Threat: Nerve disorders, damage to liver and kidneys, possible cancer

Formaldehyde Source: Furniture stuffing, paneling, particleboard, foam insulation Threat: Irritation of eyes, throat, skin, and lungs; nausea; dizziness

1,1,1-Trichloroethane Source: Aerosol sprays Threat: Dizziness, irregular breathing

Styrene Source: Carpets, plastic products Threat: Kidney and liver damage

Nitrogen oxides Source: Unvented gas stoves and kerosene heaters, woodstoves Threat: Irritated lungs, children's colds, headaches

Benzo-α-pyrene Source: Tobacco smoke, woodstoves Threat: Lung cancer

Particulates Source: Pollen, pet dander, dust mites, cooking smoke particles Threat: Irritated lungs, asthma attacks, itchy eyes, runny nose, lung disease

Radon-222 Source: Radioactive soil and rock surrounding foundation, water supply Threat: Lung cancer

Tobacco smoke Source: Cigarettes Threat: Lung cancer, respiratory ailments, heart disease

Asbestos Source: Pipe insulation, vinyl ceiling and floor tiles Threat: Lung disease, lung cancer

Carbon monoxide Source: Faulty furnaces, unvented gas stoves and kerosene heaters, woodstoves Threat: Headaches, drowsiness, irregular heartbeat, death

Methylene chloride Source: Paint strippers and thinners Threat: Nerve disorders, diabetes

Presenter

Presentation Notes

Figure 18-17 Numerous indoor air pollutants are found in most modern homes. Question: To which of these pollutants are you exposed?


• Indoor air pollution risk – Children under five and the elderly – Sick – Pregnant women – People with respiratory disorders or heart

problems – Smokers – Factory workers

Indoor Air Pollution Is a Serious Problem (cont’d.)


• Four most dangerous indoor air pollutants in more-developed countries – Tobacco smoke – Formaldehyde – Radioactive radon-222 gas – Very small (ultrafine) particles

• Other indoor pollutants – Pesticide residues, lead particles, air-borne

spores (mold, mildew)

Indoor Air Pollution Is a Serious Problem (cont’d.)


• Sources – Underground deposits of certain minerals

• Human health risks – Decays into Polonium-210

• Can expose the lungs to high amounts of radiation

• How can you test for and correct a radon problem?

Case Study: Radioactive Radon Gas

Case Study: Radioactive Radon Gas (cont’d.)

Fig. 18-19, p. 491

Outlet vents for furnace, dryer, and woodstove

Open window

Openings around pipes

Cracks in wall

Slab joints

Wood stove

Clothes dryer

Cracks in floor

Sump pump Furnace

Uranium-238 Radon-222 gas

Soil

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Presentation Notes

Figure 18.19: There are a number of ways that radon-222 gas can enter homes and other buildings. Question: Have you tested the indoor air where you live for radon-222?


• Air pollution can contribute to: – Asthma – Chronic bronchitis – Emphysema – Lung cancer – Heart attack – Stroke

18-5: What Are the Health Effects of Air Pollution?


• The respiratory system protects from air pollutants through: – Hair – Cilia – Mucus

• Effects of smoking and prolonged air pollution exposure – Chronic bronchitis – Emphysema

Your Body’s Natural Defenses Against Air Pollution Can Be Overwhelmed


Major Components of the Human Respiratory System

Fig. 18-21, p. 492

Epithelial cell

Cilia Nasal cavity

Oral cavity Goblet cell (secreting mucus)

Pharynx (throat)

Mucus Trachea (windpipe)

Bronchus Bronchioles

Right lung Alveolar duct

Bronchioles Alveolar

sac (sectioned)

Alveoli

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Presentation Notes

Figure 18.21: Major components of the human respiratory system can help to protect you from air pollution, but these defenses can be overwhelmed or breached.


• 3.2 million deaths per year worldwide – Mostly in Asia; 1.2 million in China – 150,000 to 350,000 in the United States

• EPA proposed stricter emission standards for diesel-powered vehicles – 125,000 die in U.S. each year from diesel

fumes – Emissions from one truck = 150 cars

Air Pollution Is a Big Killer


Premature Deaths from Air Pollution in the U.S.

Fig. 18-22, p. 493

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Presentation Notes

Figure 18.22: Distribution of premature deaths from air pollution in the United States, mostly from very small, fine, and ultra-fine particles added to the atmosphere by coal-burning power plants. Questions: Why do the highest death rates occur in the eastern half of the United States? If you live in the United States, what is the risk at your home or where you go to school?


• Legal, economic, and technological tools can help us to clean up air pollution

• However, the best solution is to prevent it

18-6: How Should We Deal with Air Pollution?


• United States – Clean Air Acts: 1970, 1977, and 1990 created

regulations enforced by states and cities • EPA

– National ambient air quality standards for six outdoor pollutants

• Carbon monoxide, nitrogen dioxide, sulfur dioxide, suspended particulate matter, ozone, and lead

Laws and Regulations Can Reduce Outdoor Air Pollution


• EPA’s national emission standards for 188 hazardous air pollutants (HAPs)

• Toxic Release Inventory (TRI)

• Some successes in the United States – Decrease in emissions – Use of low-sulfur diesel fuel

• Less-developed countries – Have more challenges with reducing air

pollution

Laws and Regulations Can Reduce Outdoor Air Pollution (cont’d.)


• Emission trading or cap-and-trade program – Success depends on:

• How low initial cap is set • How often it is lowered

We Can Use the Marketplace to Reduce Outdoor Air Pollution


• Stationary source air pollution • Motor vehicle air pollution • Less-developed countries are far behind

developed countries in implementing solutions – Non-existent and/or weak laws

There Are Many Ways to Reduce Outdoor Air Pollution

Solutions

Stationary Source Air Pollution

Prevention Reduction or Disposal

Burn low-sulfur coal or remove sulfur from coal

Convert coal to a liquid or gaseous fuel

Remove pollutants from smokestack gases

Switch from coal to natural gas and renewables

Tax each unit of pollution produced

Disperse emissions (which can increase downwind pollution) with tall smokestacks

Fig. 18-25, p. 495

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Presentation Notes

Figure 18.25 There are several ways to prevent, reduce, or disperse emissions of sulfur oxides, nitrogen oxides, and particulate matter from stationary sources such as coal-burning power plants and industrial facilities (Concept 18-6). Questions: Which two of these solutions do you think are the most important? Why?

Fig. 18-26, p. 496

Motor Vehicle Air Pollution

Prevention Cleanup

Walk bike or use mass transit

Require emission control devices

Inspect car exhaust systems twice a year

Improve fuel efficiency

Get older, polluting cars off the road

Set strict emission standards

Solutions

Presenter

Presentation Notes

Figure 18.26: There are a number of ways to prevent and reduce emissions from motor vehicles (Concept 18-6). To find out what and how much your car emits, go to www.cleancarsforkids.org. Questions: Which two of these solutions do you think are the most important? Why?


• Greater threat to human health than outdoor pollution

• What can be done? – Prevention – Cleanup

Reducing Indoor Air Pollution Should Be a Priority

Fig. 18-27, p. 496

Indoor Air Pollution

Prevention

Ban indoor smoking Use adjustable fresh air vents for work spaces

Reduction and Dilution

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

Circulate air more frequently

Circulate a building’s air through rooftop greenhouses

Prevent radon infiltration

Use less polluting cleaning agents, paints, and other products

Use efficient venting systems for wood-burning stoves

Solutions

Presenter

Presentation Notes

Figure 18.27: There are several ways to prevent or reduce indoor air pollution. Questions: Which two of these solutions do you think are the best ones? Why?


• How can we avoid producing these pollutants in the first place? – Place political and economic pressure on

government officials and companies

We Can Emphasize Pollution Prevention


• Widespread use of certain chemicals has: – Reduced ozone levels in the stratosphere – Allowed more harmful ultraviolet radiation to

reach the earth’s surface • To reverse ozone depletion:

– Stop producing ozone-depleting chemicals – Adhere to the international treaties that ban

such chemicals

18-17: How Have We Depleted Ozone in the Stratosphere & What Can We Do?


• Ozone is thinning over Antarctica and the Arctic

• Chlorofluorocarbons (CFCs) – Persistent chemicals that attack ozone in the

stratosphere

Our Use of Certain Chemicals Threatens the Ozone Layer


Ozone Degradation

Fig. 18-30, p. 498

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Presentation Notes

Figure 18-30: Natural Capital Degradation: These colorized satellite images show ozone thinning over Antarctica during September of 1980 (left), 2000 (center), and 2011 (right). Ozone depletion of 50% or more occurred in the dark blue and purple areas.


• Ozone protects the earth’s surface from damaging UV radiation – Human health concerns – UV radiation affects plankton

Why Should We Worry About Ozone Depletion?


• Stop producing ozone-depleting chemicals immediately

• Agreements with a prevention approach: – Montreal Protocol

• Cut emissions of CFCs

– Copenhagen Amendment • Accelerated phase-out

We Can Reverse Stratospheric Ozone Depletion


• Outdoor air pollution, in the forms of industrial smog, photochemical smog, and acid deposition, and indoor air pollution are serious global problems

• Each year, at least 2.4 million people die prematurely from the effects of air pollution; indoor air pollution, primarily in less-developed countries, causes about two-thirds of those deaths

Big Ideas


• We need to give top priority status to the prevention of outdoor and indoor air pollution throughout the world and the reduction of stratospheric ozone depletion

Big Ideas (cont’d.)


• Three principles of sustainability – Rely more on direct and indirect forms of solar

energy than on fossils fuels – Recycle and reuse much more of what we

use – Use a diverse set of nonpolluting or low-

polluting renewable energy resources

Tying it All Together

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