LIVING IN THE ENVIRONMENT, 18e
G. TYLER MILLER • SCOTT E. SPOOLMAN
18
Air Pollution
©©
Cengage
Learning
2015
Cengage
Learning
2015
Core Case Study: South Asia’s
Massive Brown Clouds
• 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
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The South Asia's Brown Clouds (cont'd.)
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Fig. 18-1a, p. 474
18-1: What is the Nature of the
Atmosphere?
• The two innermost layers of the
atmosphere
– Troposphere – supports life
– Stratosphere – contains the protective ozone
layer
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The Atmosphere Consists of
Several Layers
• 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
© Cengage Learning 2015
Atmospheric pressure (millibars)
Temperature
Mesosphere
Stratosphere
Altitude (miles)
Altitude (kilometers)
Thermosphere
Ozone layer
Pressure
(Sea
level)
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Troposphere
Temperature (˚C)
Pressure = 1,000 millibars
at ground level
Fig. 18-2, p. 475
Air Movements in the Troposphere Play a
Key Role in Earth’s Weather and Climate
• 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
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The Stratosphere Is Our Global Sunscreen
• 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
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18-2: What Are the Major Outdoor
Pollution Problems?
• 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
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Air Pollution Comes from Natural and
Human Sources
• 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
© Cengage Learning 2015
Air Pollution Comes from Natural and
Human Sources (cont’d.)
• Human sources
– Mostly in industrialized and/or urban areas
– Stationary sources – power plants and
industrial facilities
– Mobile sources – motor vehicles
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Some Pollutants in the Atmosphere
Combine to Form Other Pollutants
• Primary pollutants
– Emitted directly into the air
• Secondary pollutants
– From reactions of primary pollutants
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Sources and Types of Air Pollutants
Primary Pollutants
CO CO2
SO2
NO NO N2O
2
CH4 and most
other hydrocarbons
Most suspended particles
Natural
Source
Stationary
Secondary Pollutants
SO3
HNO3 H2SO4
H2O2 O3 PANs
Most NO3– and SO42– salts
Human Source
Human Source
Mobile
© Cengage Learning 2015
Fig. 18-3, p. 477
What Are the Major Outdoor Air
Pollutants?
• Carbon oxides
– Carbon monoxide (CO); carbon dioxide (CO2)
• Nitrogen oxides (NO) and nitric acid
(HNO3)
– Acid deposition; photochemical smog
• Does the benefit of the lessened
atmospheric warming due to the South
Asian Brown Clouds outweigh their
harmful effects?
© Cengage Learning 2015
What Are the Major Outdoor Air
Pollutants? (cont’d.)
• Sulfur dioxide (SO2) and sulfuric acid
(H2SO4)
• Particulates
– Suspended particulate matter
• Ozone
• Volatile organic compounds (VOCs)
– Methane
© Cengage Learning 2015
Chemical Reactions That Form Major
Outdoor Air Pollutants
Table 18-1, p. 480
Acid Deposition
© Cengage Learning 2015
Fig. 18-4, p. 478
Case Study: Lead Is a Highly
Toxic Pollutant
• In air, water, soil, plants, and animals
• Does not break down in the environment
• Impacts human health and environment
– Children are most vulnerable
– Can cause death, brain damage, and
paralysis
• How can we reduce lead in the
environment?
© Cengage Learning 2015
Burning Coal Produces Industrial Smog
• 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?
© Cengage Learning 2015
Ammonium sulfate [(NH4)2SO4]
Ammonia (NH3)
Sulfuric acid (H2SO4)
Water vapor (H2O)
Sulfur trioxide (SO 3 )
Carbon monoxide (CO)
and
carbon dioxide (CO2)
Oxygen (O2)
Sulfur dioxide (SO2)
Burning coal and oil
Oxygen (O2)
© Cengage Learning 2015
Sulfur (S) in
coal and oil
Carbon (C) in
coal and oil
Stepped Art
Fig. 18-8, p. 481
Sunlight Plus Cars Equals Photochemical
Smog
• Photochemical smog
• VOCs + NOx + Heat + Sunlight yields:
– Ground level O3 and other photochemical
oxidants
– Aldehydes
– Other secondary pollutants
© Cengage Learning 2015
PANS and other pollutants
Volatile organic
compounds
(VOCs)
Ozone (O3)
Photochemical Smog
Oxygen (O2)
Nitric oxide (NO) +
Oxygen atom (O)
Water vapor (H2O)
UV radiation Hydrocarbons
Peroxyacyl
Nitrogen dioxide (NO2)
nitrates (PANs)
Oxygen (O2)
Nitric oxide (NO)
Oxygen (O2)
Burning fossil fuels
© Cengage Learning 2015
Nitrogen (N) in
fossil fuel
Fig. 18-9, p. 483
Several Factors Can Decrease or Increase
Outdoor Air Pollution
• 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
© Cengage Learning 2015
Several Factors Can Decrease or Increase
Outdoor Air Pollution (cont’d.)
• 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
© Cengage Learning 2015
A Temperature Inversion
Descending warm air mass
Warmer air
Inversion layer
Inversion layer
Sea breeze
Increasing
altitude
Decreasing temperature
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Fig. 18-11, p. 484
18-3: What Is Acid Deposition and
Why Is It a Problem?
• 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
© Cengage Learning 2015
Acid Disposition Is a Serious Regional Air
Pollution Problem
• Acid deposition
– Sulfuric acid and nitric acid compounds
– Wet deposition – rain, snow, fog, cloud vapor
– Dry deposition – particles
• Substances remain in the atmosphere 214 days
• What are some ways in which your daily
activities contribute to acid deposition?
© Cengage Learning 2015
Natural Capital Degradation: Acid
Deposition
Wind
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
Nitric oxide (NO)
Sulfur dioxide
(SO2) and NO
Wet acid deposition
(droplets of H2SO4 and
HNO3 dissolved
in rain and snow)
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
© Cengage Learning 2015
Fig. 18-12, p. 485
Current and Possible Future Acid Rain
Problem Areas
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Fig. 18-13, p. 486
Acid Deposition Has a Number of Harmful
Effects
• 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.
© Cengage Learning 2015
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
Remove SO2 and NOx
from smokestack
gases and remove
NOx from motor
vehicular exhaust
Add phosphate
fertilizer to
neutralize
acidified lakes
Add lime to
neutralize
acidified soils
Tax SO2 emissions
© Cengage Learning 2015
Fig. 18-15, p. 488
18-4: What Are the Major Indoor Air
Pollution Problems?
• The most threatening indoor air pollutants:
– Smoke and soot from the burning of wood
and coal in cooking fires (mostly in lessdeveloped countries)
– Cigarette smoke
– Chemicals used in building materials and
cleaning products
© Cengage Learning 2015
Indoor Air Pollution Is a Serious
Problem
• 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
© Cengage Learning 2015
Chloroform Source:
Chlorine-treated water in hot
showers
Possible threat: Cancer
Para-dichlorobenzene
Source: Air fresheners,
mothball crystals
Threat: Cancer
1,1,1-Trichloroethane
Source: Aerosol sprays
Threat: Dizziness,
irregular breathing
Tetrachloroethylene
Source: Dry-cleaning
fluid fumes on
clothes Threat:
Nerve disorders,
damage to liver and
kidneys, possible
cancer
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
Asbestos
Source: Pipe insulation,
vinyl ceiling and floor tiles
Threat: Lung disease, lung
cancer
Formaldehyde
Source: Furniture stuffing,
paneling, particleboard,
foam insulation
Threat: Irritation of eyes,
throat, skin, and lungs;
nausea; dizziness
Tobacco smoke
Source: Cigarettes
Threat: Lung cancer,
respiratory ailments,
heart disease
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
Radon-222
Source:
Radioactive soil
and rock
surrounding
foundation, water
supply
Threat: Lung
cancer
Fig. 18-17, p. 489
Indoor Air Pollution Is a Serious
Problem (cont’d.)
• Indoor air pollution risk
– Children under five and the elderly
– Sick
– Pregnant women
– People with respiratory disorders or heart
problems
– Smokers
– Factory workers
© Cengage Learning 2015
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)
© Cengage Learning 2015
Case Study: Radioactive Radon Gas
• 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?
© Cengage Learning 2015
Case Study: Radioactive Radon Gas (cont’d.)
Outlet vents for furnace, dryer, and woodstove
Open
window
Cracks in wall
Openings
around pipes
Slab joints
Wood stove
Clothes
Furnace dryer
Cracks
in floor
Sump
pump
Radon-222 gas
Uranium-238
Soil
Fig. 18-19, p. 491
18-5: What Are the Health Effects of Air
Pollution?
• Air pollution can contribute to:
– Asthma
– Chronic bronchitis
– Emphysema
– Lung cancer
– Heart attack
– Stroke
© Cengage Learning 2015
Your Body’s Natural Defenses Against Air
Pollution Can Be Overwhelmed
• The respiratory system protects from air
pollutants through:
– Hair
– Cilia
– Mucus
• Effects of smoking and prolonged air
pollution exposure
– Chronic bronchitis
– Emphysema
© Cengage Learning 2015
Major Components of the Human
Respiratory System
Epithelial
cell
Cilia
Nasal cavity
Oral cavity
Goblet cell
(secreting
mucus)
Pharynx (throat)
Trachea (windpipe)
Mucus
Bronchus
Bronchioles
Right lung
Alveolar
duct
Bronchioles
Alveolar
sac
(sectioned)
Alveoli
© Cengage Learning 2015
Fig. 18-21, p. 492
Air Pollution Is a Big Killer
• 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
© Cengage Learning 2015
Premature Deaths from Air Pollution in the
U.S.
© Cengage Learning 2015
Fig. 18-22, p. 493
18-6: How Should We Deal with Air
Pollution?
• Legal, economic, and technological tools
can help us to clean up air pollution
• However, the best solution is to prevent it
© Cengage Learning 2015
Laws and Regulations Can Reduce
Outdoor 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
© Cengage Learning 2015
Laws and Regulations Can Reduce
Outdoor Air Pollution (cont’d.)
• 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
© Cengage Learning 2015
We Can Use the Marketplace to Reduce
Outdoor Air Pollution
• Emission trading or cap-and-trade
program
– Success depends on:
• How low initial cap is set
• How often it is lowered
© Cengage Learning 2015
There Are Many Ways 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
© Cengage Learning 2015
Solutions
Stationary Source Air Pollution
Prevention
Burn low-sulfur
coal or remove
sulfur from coal
Convert coal to a
liquid or gaseous
fuel
Switch from coal to
natural gas and
renewables
Reduction or
Disposal
Disperse emissions
(which can increase
downwind
pollution) with tall
smokestacks
Remove pollutants
from smokestack
gases
Tax each unit of
pollution produced
Fig. 18-25, p. 495
Solutions
Motor Vehicle Air Pollution
Prevention
Cleanup
Walk bike or use
mass transit
Require emission
control devices
Improve fuel efficiency
Get older, polluting
cars off the road
Inspect car
exhaust systems
twice a year
Set strict emission
standards
Fig. 18-26, p. 496
Reducing Indoor Air Pollution Should
Be a Priority
• Greater threat to human health than
outdoor pollution
• What can be done?
– Prevention
– Cleanup
© Cengage Learning 2015
Solutions
Indoor Air Pollution
Prevention
Ban indoor smoking
Set stricter
formaldehyde
emissions
standards for
carpet, furniture,
and building
materials
Prevent radon
infiltration
Use less polluting
cleaning agents,
paints, and other
products
Reduction and
Dilution
Use adjustable
fresh air vents
for work spaces
Circulate air more
frequently
Circulate a
building’s air
through rooftop
greenhouses
Use efficient venting
systems for woodburning stoves
Fig. 18-27, p. 496
We Can Emphasize Pollution Prevention
• How can we avoid producing these
pollutants in the first place?
– Place political and economic pressure on
government officials and companies
© Cengage Learning 2015
18-17: How Have We Depleted Ozone in
the Stratosphere & What Can We Do?
• 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
© Cengage Learning 2015
Our Use of Certain Chemicals Threatens
the Ozone Layer
• Ozone is thinning over Antarctica and the
Arctic
• Chlorofluorocarbons (CFCs)
– Persistent chemicals that attack ozone in the
stratosphere
© Cengage Learning 2015
Ozone Degradation
© Cengage Learning 2015
Fig. 18-30, p. 498
Why Should We Worry About Ozone
Depletion?
• Ozone protects the earth’s surface from
damaging UV radiation
– Human health concerns
– UV radiation affects plankton
© Cengage Learning 2015
We Can Reverse Stratospheric Ozone
Depletion
• Stop producing ozone-depleting chemicals
immediately
• Agreements with a prevention approach:
– Montreal Protocol
• Cut emissions of CFCs
– Copenhagen Amendment
• Accelerated phase-out
© Cengage Learning 2015
Big Ideas
• 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
© Cengage Learning 2015
Big Ideas (cont’d.)
• 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
© Cengage Learning 2015
Tying it All Together
• 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 lowpolluting renewable energy resources
© Cengage Learning 2015