Transcript What Are the Major Outdoor Air Pollutants? (2)

Air Pollution
Chapter 18
Core Case Study: South Asia’s
Massive Brown Cloud
 Asian Brown Cloud
• Causes
• Chemical composition
• Areas impacted
 Air pollution connects the world
 Steps taken in China and India to reduce air
pollution
 The winter of 2012/2013 has been bad!
18-1 What Is the Nature of the
Atmosphere?
 Concept 18-1 The atmosphere is structured in
layers, including the troposphere, which
supports life, and the stratosphere, which
contains the protective ozone layer.
The Atmosphere Consists of
Several Layers
 Atmosphere varies in
• Density
• Atmospheric pressure
• Temperature
Air Movements in the Troposphere Play a
Key Role in Earth’s Weather and Climate
 Troposphere
75–80% of the earth’s air mass
Closest to the earth's surface
Chemical composition of air
Rising and falling air currents: weather and
climate
• Involved in chemical cycling
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The Stratosphere Is Our Global
Sunscreen
 Stratosphere
• Similar composition to the troposphere, with 2
exceptions
• Much less water
• O3, ozone layer, filters UV
• Location
Trophosphere/stratosphere
18-2 What Are the Major Outdoor
Pollution Problems?
 Concept 18-2 Pollutants mix in the air to form
industrial smog, mostly the result of burning
coal, and photochemical smog, caused by motor
vehicle, industrial, and power plant emissions.
Note: This sign is in Dinosaur National
Monument at a beautiful overlook.
Air Pollution Comes from Natural
and Human Sources
 Air pollution
 Natural sources
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Dust blown by wind
Pollutants from wildfires and volcanoes
Volatile organics released by plants
Withdrawing groundwater
 Human sources: mostly in industrialized and/or
urban areas
• Stationary sources
• Mobile sources
Case Study: Air Pollution in the
Past: The Bad Old Days
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Discovery of fire
Middle Ages
Industrial Revolution
London, England
• 1850s; 1952: yellow fog; Clean Air Act of 1956
 United States
• 1948: Donora, PA; first U.S. air pollution disaster
• Donora Death Fog
• 1963: New York City
 Global problem
Denora Death Fog
Some Pollutants in the Atmosphere
Combine to Form Other Pollutants
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Primary pollutants
Secondary pollutants
Air quality improving in developed countries
Much more needs to be done in developing
countries
• Indoor pollution: big threat to the poor
 Discuss: How do primary pollutants become
secondary pollutants? In ______ words.
What Are the Major Outdoor Air
Pollutants? (1)
 Carbon oxides
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Carbon monoxide (CO)
Carbon dioxide (CO2)
Sources
Human health and environmental impact
 Ozone (O3)
• Sources
• Human and environmental impact
 Discuss: Ozone is good/ ozone is bad. In ___
words.
What Are the Major Outdoor Air
Pollutants? (2)
 Review: Draw the N cycle and the S cycle.
Do not look them up.
 Nitrogen oxides (NOx) and nitric acid (HNO3)
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Sources
Acid deposition
Photochemical smog
Human health and environmental impact
 Sulfur dioxide (SO2) and sulfuric acid (H2SO4)
• Sources
• Human health and environmental impact
What Are the Major Outdoor Air
Pollutants? (3)
 Particulates
• Suspended particulate matter (SPM)
• Fine
• Ultrafine
• Sources
• Human health and environmental impact
 Volatile organic compounds (VOCs)
• Hydrocarbons and terpenes
• Sources
• Human and environmental impact
Science Focus: Detecting Air
Pollutants
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Chemical instruments
Satellites
Nanotechnology
Biological indicators
• Lichens
Case Study: Lead Is a Highly Toxic
Pollutant
 Does not break down in the environment
 Sources
 Human health and environmental impact
• Most vulnerable
 Reduction of lead (Pb)
• Unleaded gasoline
• Unleaded paint
 Still problems
• 2007: toys with Pb paint recalled
• Global ban on lead in gasoline and paint
Burning Coal Produces Industrial
Smog
 Chemical composition of industrial smog
 Reduction of this smog in urban cities of the
United States
 China and smog
• Human deaths
Sunlight Plus Cars Equals
Photochemical Smog
 Photochemical Smog
• Chemical composition
• Sources
 VOCs + NO2 + Heat + Sunlight yields
• Ground level O3 and other photochemical
oxidants
• Aldehydes
• Other secondary pollutants
 Human health and environmental impact
Several Factors Can Decrease or
Increase Outdoor Air Pollution (1)
 Outdoor air pollution may be decreased by:
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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 (2)
 Outdoor air pollution may be increased by:
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Urban buildings
Hills and mountains
High temperatures
Emissions of VOCs from certain trees and plants
Grasshopper effect
Temperature inversions
18-3 What Is Acid Deposition and
Why Is It a Problem?
 Concept 18-3 Acid deposition is caused mainly
by coal-burning power plant and motor vehicle
emissions, and in some regions, threatens
human health, aquatic life and ecosystems,
forests, and human-built structures.
Acid Disposition Is a Serious
Regional Air Pollution Problem
 Acid deposition, acid rain
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Formation
Local versus regional problems
Effects of prevailing winds
Buffers
Where is the worst acid deposition?
Acid Deposition Has a Number of
Harmful Effects
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Human respiratory disorders
Aquatic ecosystems affected
Release of toxic metals
Leaching of soil nutrients
Loss of crops and trees
Damage to buildings, statues,
monuments
and
We Know How to Reduce Acid
Deposition
 Prevention approaches
 Clean up
• Add lime to neutralize acidified lakes and soil
• Add phosphate fertilizer to neutralize acidified
lakes
18-4 What Are the Major Indoor Air
Pollution Problems?
 Concept 18-4 The most threatening indoor air
pollutants are smoke and soot from wood and
coal cooking fires (a hazard found mostly in
developing countries) and chemicals used in
building materials and products.
Indoor Air Pollution Is a Serious
Problem (1)
 Developing countries
• Indoor burning
• Poor suffer the greatest risk
 Developed countries
• Indoor air pollution is greater than outdoor air
pollution
 Why?
• 11 of the common air pollutants higher inside than
outside
• Greater in vehicles than outside
• Health risks magnified: people spend 70–98% of their
time is indoors
Indoor Air Pollution Is a Serious
Problem (2)
 Who are at greatest risk from indoor air
pollution?
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Children under 5 and the elderly
Sick
Pregnant women
People with respiratory disorders or heart
problems
• Smokers
• Factory workers
Indoor Air Pollution Is a Serious
Problem (3)
 Four most dangerous indoor air pollutants:
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Tobacco smoke
Formaldehyde
Radioactive radon-222 gas
Very small particles
 Sources of these pollutants
 Human health risks
Indoor Air Pollution Is a Serious
Problem (5)
 Other possible indoor air pollutants:
• Pesticide residue
• Pb particles
• Living organisms and their excrements
• E.g., Dust mites and cockroach droppings
• Airborne spores of molds and mildews
 Sick-building syndrome
Case Study: Radioactive Radon Gas
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Sources
Human health risks
Testing for radon
Correcting a radon
problem
18-5 What Are the Health Effects of
Air Pollution?
 Concept 18-5 Air pollution can contribute to
asthma, chronic bronchitis, emphysema, lung
cancer, heart attack, and stroke.
Your Body’s Natural Defenses
against Air Pollution Can Be
Overwhelmed
 Respiratory system protection from air pollutants
• Role of cilia, mucus, sneezing, and coughing
 Effect of smoking and prolonged air pollution
exposure
• Chronic bronchitis
• Emphysema
Air Pollution Is a Big Killer
 3 Million deaths per year world-wide
• Mostly in Asia
• Main causes
 EPA: proposed stricter emission standards for
diesel-powered vehicles
 Link between international trade and air pollution
• Cargo ships and pollution
Naples, Italy – 2008 Smog from burned trash
18-6 How Should We Deal with Air
Pollution?
 Concept 18-6 Legal, economic, and
technological tools can help to clean up air
pollution, but much greater emphasis should be
focused on preventing air pollution.
Laws and Regulations Can Reduce
Outdoor Air Pollution
 United States
• Clean Air Acts: 1970, 1977, and 1990
 EPA
• National ambient air quality standards (NAAQs)
for 6 outdoor criteria pollutants
• National emission standards for 188 hazardous
air pollutants (HAPs)
• Toxic Release Inventory (TRI)
Laws and Regulations Can Reduce
Outdoor Air Pollution
 Good news in U.S.
• Decrease in emissions
• Use of low-sulfur diesel fuel: cuts pollution
 Developing countries: more air pollution
 What does a scrubber look like?
Case Study: U.S. Air Pollution Can
Be Improved
 Rely on cleanup more than prevention of
pollution
 Raise fuel-efficiency for cars, SUVs, and light
trucks
 Better regulation of emissions of motorcycles
and two-cycle gasoline engines
 Regulate air pollution for oceangoing ships in
American ports
Case Study: U.S. Air Pollution Can
Be Improved
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Why are airports exempt from many regulations?
Regulate greenhouse gas emissions
Ultrafine particles are not regulated
Urban O3 levels too high
What about indoor air pollution?
Better enforcement of the Clean Air Acts
Is intense pressure needed from citizens to
make improvements?
We Can Use the Marketplace to
Reduce Outdoor Air Pollution
 Emission trading or cap-and-trade program
• Mixed reactions to program
• SO2 emissions down significantly
• NO2 will be tried in the future
There Are Many Ways to Reduce
Outdoor Air Pollution
 1980 –2006
• SO2 emissions from U.S. electric power plants
decreased by 66%
• NOx emissions by 41%
• Particulate emissions by 28%
 Older plants not governed by the same
regulations
Reducing Indoor Air Pollution
Should Be a Priority
 Greater threat to human health than outdoor
pollution
 What can be done?
• Prevention
• Cleanup
We Need to Put More Emphasis on
Pollution Prevention
 Output approaches
 New shift to preventing outdoor and indoor
pollution
• Pressure from citizens