Download Air Pollution, Climate Change, and Ozone Depletion

Layering of the Earth’s Atmosphere
Air Pollution, Climate Change, and
Ozone Depletion
Chapter 15
Temperature
Earth’s Atmosphere
Pressure
Thermosphere
ƒ Troposphere(對流層)
Mesopause
• 75–80% earth’s air mass
• 78% N2, 21% O2
Mesosphere
Stratopause
ƒ Stratosphere(平流層)
Stratosphere
Tropopause
Ozone layer----好的 臭氧(吸收紫外線)
約海平面上17-30km
Ozone layer
Troposphere
Fig. 15-2, p. 346
15-1 What Are the Major Air Pollution
Problems? (1)
15-1 What Are the Major Air Pollution
Problems? (2)
ƒ Concept 15-1A Three major outdoor air
pollution problems are工業煙霧 industrial smog
(smoke + fog) from burning coal,光化學煙霧
photochemical smog from motor vehicle and
industrial emissions, and 酸性沉降 acid
deposition from coal burning and motor vehicle
exhaust.
ƒ Concept 15-1B The most threatening indoor air
pollutants are smoke and soot 油煙 from wood
and coal fires (in developing countries) and
chemicals used in building materials and
products (in developed countries).
Outdoor Air Pollution
Mount Pinatubo in the Philippines
on June 12, 1991 (菲律賓 皮納土波火山)
ƒ What is air pollution?
污染物濃度高到足以傷害生物或物質
並使氣候產生變化
ƒ Outdoor and Indoor air pollution
ƒ Natural and Human Sources*
ƒ Stationary and mobile sources*
固定污染源
移動污染源
ƒ Primary pollutants (初級污染物)(一次污染物)
ƒ Secondary pollutants (次級污染物)(二次污染物)
Fig. 15-1, p. 344
Core Case Study: Volcanoes and
Climate Change
Sources and Types of Air Pollutants
ƒ Study volcano to understand climate change
ƒ Mount Pinatubo – 1991
• Second largest volcanic eruption of 20th century
(the largest----Alaska, 1912)
• Massive release of air pollution globally
ƒ Opportunity to test climate models
ƒ Predictions matched observations
Types of Major Air Pollutants
Primary Pollutants
CO CO2
SO2 NO NO2
Most hydrocarbons
Most suspended particles
Secondary Pollutants
SO3
HNO3 H2SO4
H2O2 O3 PANs
Most NO3– and SO42– salts
Sources
Natural
Stationary
Mobile
Fig. 15-3, p. 347
ƒ Carbon oxides (CO, CO2)
ƒ Nitrogen oxides and nitric acid (NO, NO2, HNO3)
ƒ Sulfur dioxide and sulfuric acid (SO2, SO3,
H2SO4)
ƒ Particulates (SPM--- suspended particulate matter)
(PM-10, PM-2.5)
ƒ Ozone (O3)
ƒ Volatile organic compounds (VOCs, e.g. CH4,
C6H6)
ƒ Radioactive radon (Rn) 氡
Science Focus: Using Lichens(地衣)
to Detect Air Pollution
Lichens Growing on Slate Rock (黏板岩)
ƒ Indicators of air pollution
• Mine canaries---金絲雀偵測甲烷
• Lichens (真菌+藻類的共生物) *
Isle Royale in Lake Superior
(蘇必略湖 羅耀拉島
有二氧化硫的污染 利用地衣指出
污染源來自加拿大桑德灣的燃煤工廠)
Fig. 15-A, p. 348
Industrial Smog 工業煙霧
Photochemical Smog 光化學煙霧
ƒ Gray-air smog
ƒ Brown-air smog (reddish-brown NO2)
ƒ Burning coal in power plants and factories
• Sulfur dioxide, sulfuric acid, suspended particles
ƒ Developed versus developing countries
• Air pollution control in the U.S. and Europe
• China, India, Ukraine, Eastern Europe (no air
pollution control)
ƒ Sunlight + cars → Photochemical smog
ƒ Photochemical reactions*
Photochemical Smog
ƒ A mixture of primary and secondary pollutants.
Forms when primary pollutants interact under the
influence of sunlight.
ƒ Two most destructive components:
• Ozone (臭氧)
• Peroxyacetyl Nitrates (過氧乙醯硝酸鹽) (PAN)
ƒ Large cities ringed by mountains tend to have
trouble with photochemical smog.*
Daily Changes in Photochemical Smog
Fig. 15-4, p. 373
Natural Factors That Reduce
Outdoor Air Pollution
Natural Factors That Increase
Outdoor Air Pollution
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Particles heavier than air
Rain and snow
Salty sea spray from oceans
Winds
Chemical reactions
(ex. SO2→ SO3 → H2SO4 → acid rain → land)
Thermal Inversion
Urban buildings
Hills and mountains
High temperatures
VOC emissions from certain trees and plants
Grasshopper effect (跳躍式的傳播)
(極地生物體出現DDT, PCBs, Pb, Hg)
ƒ Temperature inversions (溫度逆轉)*
Acid Deposition 酸性沉降*
ƒ Sulfur dioxides (SO2) and nitrogen oxides (NOx)
ƒ Wet and dry deposition (濕沉降、乾沉降)
ƒ Acid rain (pH＜5.6)
ƒ Regional air pollution*
• Coal-burning power plants
• Prevailing winds (盛行風)
Acid Deposition
Wind
Transformation
to sulfuric acid
(H2SO4) and nitric
acid (HNO3)
Nitric oxide (NO)
Windborne ammonia gas
and some soil particles partially
neutralize acids and form dry
sulfate and nitrate salts
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
Fig. 15-4, p. 351
Current and Potential Problems with
Acid Deposition
Harmful Effects of Acid Deposition
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Fig. 15-5, p. 351
Respiratory diseases in humans*
Toxic metal leaching from soils and rocks
Structural damage*
Kills fish and other aquatic organisms*
Leaches plant nutrients from soil*
Acid clouds and fog at mountaintops*
Structural
Damage
Healthy and Diseased Lungs
Fig. 15-10, p. 356
Aquatic Organism is killed
Impacts of Air Pollution on Trees
and Water (leaching nutrients)
Mountaintop is damaged
by acid cloud and acid fog
Emissions
NOx
SO2
Acid
depositionH2O2 O3
PANs Others
Direct damage to
leaves and bark
Reduced
photosynthesis
and growth
Soil acidification
Leaching
of soil
nutrients
Acids
Release of
toxic
metal ions
Increased
susceptibility to
drought, extreme
cold, insects,
mosses, and
disease organisms
Tree death
Root
damage
Reduced nutrient
and water uptake
Lake
Groundwater
Fig. 15-6, p. 353
Reducing Acid Deposition
Indoor Air Pollution
ƒ Often higher concentration in buildings and cars
(in buildings 2-5 times, in cars 18 times)
ƒ Most time is spent indoors or in cars
(70-98% of time)
ƒ EPA – top cancer risk
Fig. 15-7, p. 353
ƒ Sick-building syndrome (SBS)
(dizziness, headaches, coughing, nausea etc.)
Major Indoor Air Pollutants
Important Indoor Air Pollutants
In Developed Countries*
ƒ Tobacco smoke
ƒ Formaldehyde (甲醛, HCHO)
ƒ Radioactive radon-222 gas (Rn-222)
ƒ Very small particles
In Developing Countries
ƒ Particulates ←Indoor cooking and heating
Chloroform
Source: Chlorine-treated water in
hot showers
Possible threat: Cancer
Para-dichlorobenzene Tetrachloroethylene
Source: Air fresheners, Source: Dry-cleaning
fluid fumes on clothes
mothball crystals
Threat: Nerve disorders,
Threat: Cancer
damage to liver and
kidneys, possible cancer
1,1,1-Trichloroethane
Source: Aerosol sprays
Threat: Dizziness,
irregular breathing
Nitrogen oxides
Source: Unvented gas
stoves and kerosene
heaters, woodstoves
Threat: Irritated lungs,
children's colds,
headaches
Particulates
Source: Pollen, pet
dander, dust mites,
cooking smoke particles
Threat: Irritated lungs,
asthma attacks, itchy
eyes, runny nose,
lung disease
Asbestos
Carbon monoxide
Source: Pipe insulation, vinyl
Source: Faulty furnaces,
ceiling and floor tiles
unvented gas stoves and
Threat: Lung disease, lung cancerkerosene heaters,
woodstoves
Threat: Headaches,
drowsiness, irregular
heartbeat, death
Formaldehyde
Source: Furniture stuffing,
paneling, particleboard,
foam insulation
Threat: Irritation of eyes,
throat, skin, and lungs;
nausea; dizziness
Air Pollution and the Human
Respiratory System*
ƒ Natural protective system
Styrene
Source: Carpets,
plastic products
Threat: Kidney and
liver damage
Benzo-α-pyrene
Source: Tobacco smoke,
woodstoves
Threat: Lung cancer
Radon-222
Source: Radioactive soil
and rock surrounding
foundation, water supply
Tobacco smoke
Threat: Lung cancer
Source: Cigarettes
Threat: Lung cancer, respiratory
ailments, heart disease
Methylene chloride
Source: Paint strippers and thinners
Threat: Nerve disorders, diabetes
ƒ Lung cancer, chronic bronchitis (慢性支氣管炎),
emphysema (肺氣腫), asthma (氣喘)
ƒ Premature deaths (nearly 6600 death per day)
ƒ Fossil fuels → particulate matter
• Coal
• Diesel engines
Fig. 15-8, p. 354
Human Respiratory System
Epithelial cell
Cilia
Nasal cavity
Oral cavity
Goblet cell
(secreting
mucus)
Pharynx (throat)
Mucus
Trachea (windpipe)
Bronchioles
Bronchus
Alveolar duct
Right lung
Bronchioles
Alveoli
Alveolar sac
(sectioned)
Fig. 15-9, p. 355
15-2 How Should We Deal with
Air Pollution?
Healthy and Diseased Lungs
ƒ Concept 15-2 Legal, economic, and
technological tools can help clean up air
pollution, but scientists call for much greater
emphasis on preventing air pollution.
Fig. 15-10, p. 356
U.S. Outdoor Air Pollution Control Laws
ƒ Clean Air Acts
ƒ National Ambient Air Quality Standards (EPA)
Criteria pollutants (CO, NO, SO2, PM, O3, Pb)
ƒ Emission Standards for Hazardous Air Pollutants
Using the Marketplace to Reduce
Air Pollution
ƒ Emissions trading (cap and trade) program
排放量交易計畫
Proponents – cheaper and more efficient
Critics – companies buy their way out
ƒ Success depends on cap (限量)
ƒ Good news
Emission of pollutants decreased by 53%
Pb︰ -99% (1970-2005)
ƒ Bad news
Unaccepted level of ground-level ozone
ƒ Good news—Reduce SO2 emission by 53%
(1990→2006)
ƒ Bad news—far short of projected emissions
reduction
Solutions: Stationary Source
Air Pollution
Solutions: Motor Vehicle Air Pollution
Fig. 15-12, p. 358
Fig. 15-13, p. 359
Solutions: Indoor Air Pollution
What Can You Do?
Fig. 15-14, p. 359
Fig. 15-15, p. 360
15-3 How Might the Earth’s Temperature
and Climate Change in the Future?
Solutions: Air Pollution
ƒ Concept 15-3 Evidence indicates that the
earth’s atmosphere is warming, mostly because
of human activities, and that this will lead to
significant climate change during this century.
Fig. 15-16, p. 360
Estimated Changes in the Average
Global Temperature
Fig. 15-17c, p. 361
Past Climate Changes
Ice Cores: Records of Past Climates
ƒ Glacial and interglacial (between ice age) periods
ƒ Estimation of past temperature changes
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Analysis of radioisotopes in rocks and fossils
Plankton and radioisotopes in ocean sediments
Tiny bubbles of ancient air in Ice cores from glaciers*
Temperature at different depths of boreholes deep in
earth’s surface
Fig. 15-18, p. 361
The Greenhouse Effect
Solar
radiation
Energy in = Energy out
ƒ Earth’s natural greenhouse effect**
UV radiation
ƒ Natural greenhouse gases
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•
•
•
Reflected by
atmosphere
Water vapor (H2O)
Carbon dioxide (CO2)
Methane (CH4)
Nitrous Oxide (N2O)
Most
absorbed
by ozone
Radiated by
atmosphere
as heat
Lower Stratosphere
(ozone layer)
Visible
light
Troposphere
Heat
Absorbed
by the earth
Heat radiated
by the earth
Greenhouse
effect
ƒ Enhanced greenhouse effect
• Global warming
Fig. 3-7, p. 44
Evidence to Support Global Warming
ƒ Intergovernmental Panel on Climate Change (IPCC)
established in 1988
Warm, less
salty, shallow
current
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Cold, salty,
deep current
Fig. 5-6, p. 79
2007 IPCC report
Rise in average global surface temperature
13 warmest years on record since 1990 (1861--)
Arctic temperatures have risen twice as fast
Changes in glaciers**, rainfall patterns, hurricanes
Sea level rise in last century 4–8 inches (10-20cm)
Melting of Alaska’s Muir Glacier (1948-2004)
Average Drop in Summer Arctic Sea Ice
(1979 blue-2005 white)
Fig. 15-20, p. 363
Fig. 15-19, p. 363
Potential Consequences of Enhanced
Global Warming
Measured Average Temperatures
and Future Predictions
ƒ Rate and extent of temperature changes*
ƒ Tipping point (臨界點)
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Droughts and floods
Intense storms and hurricanes
Extinctions
Diseases
Economic and social disruption (lack of clean
water and food)
Fig. 15-C, p. 365
Factors Affecting the Earth’s Temperatureamplify or dampen the change
ƒ Ability of oceans to store or release carbon dioxide
and absorb heat from the lower atmosphere
ƒ Effects of cloud cover
(thick and continuous clouds at low altitudes
decrease surface warming;
thin and discontinuous cirrus clouds at high altitudes
increase surface warming )
ƒ Aerosol pollutants
(light-colored sulfate particles reflect sunlight,
soot and black carbon aerosols absorb sunlight)
ƒ Photosynthesis (the effect would be temporary)
Beneficial Effects of Global Warming
ƒ Less severe winters
ƒ More precipitation in dry areas
ƒ Less precipitation in wet areas
ƒ Increased food production for some areas
15-4 What Are Some Possible Effects
of a Warmer Earth?
ƒ Concept 15-4 Some areas will benefit from a
warmer climate and others will suffer from
melting ice, rising sea levels, more extreme
weather events, increased drought and floods,
and shifts in locations of wildlife habitats and
agricultural areas.
Harmful Effects of Global Warming
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Arctic ice and snow melt
Rising sea levels*
Melting permafrost(永久凍土層)
Changing ocean currents
Extreme weather (drought, flood)
Threat to biodiversity (如北極熊)
Change location of agricultural crops
Threats to human health (heat waves, infectious
diseases, hunger)
Rising Sea Levels Threaten
Low-lying Islands (Maldives馬爾地夫)
15-5 What Can We Do about Global
Warming?
ƒ Concept 15-5A We can slow the rate of climate
change by increasing energy efficiency, relying
more on renewable energy resources, and
reducing greenhouse gas emissions.
ƒ Concept 15-5B Governments can tax
greenhouse gas emissions, subsidize energy
efficiency and renewable energy use, and
cooperate internationally, and individuals and
institutions can sharply reduce their greenhouse
gas emissions.
Fig. 15-21, p. 369
Difficulties in Dealing with
Climate Change
Options to Deal with Climate Change
ƒ Problem is global
ƒ Basic approaches:
require unprecedented international cooperation
ƒ Long-lasting effects
• Drastically reduce greenhouse gas emissions
• Develop strategies to reduce its harmful effects
ƒ Long-term political issue
ƒ Mix both approaches
ƒ Impacts are not spread evenly
ƒ Governments beginning to act promptly
harmful and beneficial impacts
ƒ Change can disrupt economies and lifestyles
Removing Carbon Dioxide from
the Atmosphere
Solutions to Global Warming*
Fig. 15-22, p. 371
Oil rig
Tanker delivers
CO2 from plant
to rig
CO2 is pumped
down from rig for
disposal in deep
ocean or under
seafloor sediments
Government Roles in Reducing the
Threat of Climate Change
Coal power
plant
Tree plantation
Abandoned
oil field
Switchgrass
Crop field
CO2 is pumped
underground
Spent oil or
natural gas
reservoir
Spent coal
bed cavern
Deep, saltwater-filled cavern
Fig. 15-23, p. 372
ƒ Regulate carbon dioxide as a pollutant
ƒ Phase in carbon taxes or energy taxs
Cap total CO2 emissions and trade permits
ƒ Subsidize energy-efficient technologies
Reducing subsides for using fossil fuels…
ƒ Technology transfers
Transfer green technologies to developing countries
ƒ International climate negotiations
the Kyoto Protocol (Dec.1997)
Preparing for the Possible Harmful Effects of
Long-term Climate Change
What Can You Do?
Fig. 15-24, p. 375
15-6 How Have We Depleted Ozone in the
Stratosphere and What Can We Do about It?
Develop crops that
need less water
Waste less water
Connect wildlife
reserves with corridors
Move hazardous material storage
tanks away from coast
Move people away
from low-lying
coastal areas
Stockpile 1- to 5-year
supply of key foods
ƒ Concept 15-6A Widespread use of certain
chemicals has reduced ozone levels in the
stratosphere, which allows more harmful
ultraviolet radiation to reach the earth’s surface.
ƒ Concept 15-6B To reverse ozone depletion, we
must stop producing ozone-depleting chemicals,
and adhere to(支持) the international treaties
that ban such chemicals.
Prohibit new construction
on low-lying coastal areas
or build houses on stilts
Expand existing
wildlife reserves
toward poles
Fig. 15-25, p. 375
Image of the largest Antarctic ozone hole
ever recorded in September 2006
Human Impact on the Ozone Layer
ƒ Location and purpose of the ozone layer
lower stratosphere.
keep about 95% of the sun’s harmful UV
radiation from reaching the earth’s surface
ƒ Seasonal and long-term depletion of ozone
ƒ Causes – chlorofluorocarbons (CFCs)*
chemically unreactive, odorless, nonflammable,
nontoxic and noncorrosive compounds
Former Uses of CFCs
ƒ Coolants in air conditioners and refrigerators
ƒ Propellants in aerosol cans
ƒ Cleaning solutions for electronic parts
ƒ Fumigants for granaries and ship cargo holds
ƒ Bubbles in plastic packing foam
Individuals Matter: Banning of
Chlorofluorocarbons (CFCs)
ƒ Chemists Sherwood Rowland and Mario Molina
(University of California-Irvine,1974)
(the Nobel Prize in chemistry, 1995)
ƒ Four major conclusions
• CFCs Remain in atmosphere
• Rise into stratosphere over 11-20 years
• Break down into atoms that accelerate ozone
depletion*
• Stay in stratosphere for long periods(65-385 years)
ƒ Called for ban. Defended research against big
industry (14 years)
Table 9.7
Ozone Thinning
ƒ Seasonal changes
Antarctica, October; Arctic, February-June
ƒ More severe over Antarctica than the Arctic
Antarctica 40-50% loss; Arctic 11-38% loss
ƒ Consequences*
Effects of Ozone Depletion
Fig. 15-26, p. 377
What Can You Do?
Reversing Ozone Depletion
ƒ Stop producing ozone-depleting chemicals
(ODCs)
ƒ Slow recovery (60+ years)
ƒ Montreal Protocol (1987, Montreal, Canada)
ƒ Copenhagen Protocol
(1992, Copenhagen, Denmark)
Fig. 15-27, p. 378