Transcript WFSC 420 Chapter 22

Atmospheric Pollution
Pollutants and Atmospheric Cleansing
 Air pollutants: gases and aerosols in the
atmosphere that have harmful effects
 Living organisms
 Inanimate objects
 Level of air pollution determined by:
 The amount of pollutants entering the air
 The amount of space into which the pollutants
dispersed
 Mechanisms that remove pollutants from the air
Myths about Air Pollutants
 There are tolerable threshold levels of air
pollutants
 Dilution is the solution to air pollution
 Air pollutants can be assimilated by nature
 Air pollutants do not travel
 Air pollution accidents will not happen
The Hydroxyl Radical: Nature’s Cleanser
Major Air Pollutants
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Carbon monoxide & dioxide
Suspended particulate matter
Volatile organic compounds
Nitrogen oxides & Sulfur oxides
Ozone
 Hazardous Air Pollutants
 Heavy metals
 Volatile Organic Compounds
 Herbicides & Pesticides
Major Air Pollutant Sources
Sources of Air Pollution
 Automobiles
 Burning Fossil Fuels -->CO, CO2, Particulates, Metals, and NOx
 Transporting Fossil Fuels --> VOCs & HAPs
 Secondary Pollutants --> O3
 Coal Power Plants
 Exhaust --> CO, CO2, Particulates, Metals, NOx, SO2, & HAPs
(metals, radioactive nucleotides, and VOCs)
 Industrial Processes (chemical, dry cleaning, printing,
paints, glues, solvents, agriculture)
 Manufacturing --> HAPs, VOCs, Metals, CFCs
 Waste --> SO2, Particulates, VOCs, HAPs, and O3
Sources of Major
Air Pollutants
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Automobiles
Power Plants
Industrial Processes
Primary pollutants
derived directly from
burning fuels and
wastes
 Sulfur dioxides
 Nitrogen oxides
 Volatile Organic
Compounds
 Particulates
 Carbon monoxide
Major Pollutants: Secondary
 Secondary air pollutants are derived from reactions
that occur between primary pollutants and other
atmospheric chemicals
 Ozone
 PANs
 Acids
 Sulfuric
 nitric
Examining Specific Air
Pollutants
 Indoor Air Pollution
 Smog
 Acid Precipitation
Indoor Air Pollution
Radon
• Radioactive radon222
• Lung Cancer Threat
• Occurs in certain
geological areas
• Associated with
Uranium and organic
materials in rock
Reducing Indoor
Air Pollution
Smog
 The most visible air pollution
 Two types of smog
 Brown photochemical
 Gray industrial
 Directly linked to human behavior
Impacts of Smog: Temperature
Inversion
Particulates
Comparison of Growth vs. Emissions
Acid Deposition
pH Scale
pH = measurement of H+ ions in solution
Acid precipitation = pH <5.5
Major Sources of SO2 Emitters
Effects of Acid Deposition
 Alteration of plant and animal
reproduction
 Leaching of other toxic elements, e.g.,
aluminum
 Eutrophic to oligotrophic conditions
 Total loss of biota from aquatic
ecosystems
 Alterations of food chains
Impact of Buffers on Acid Deposition
Solutions to
Acid
Deposition
Air Pollution Effects
 Adversely affects the health of organisms
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People
Other Animals
Crops
Forests
 Highly corrosive to Structures
 Metal
 Stone
Impacts of Air Pollutants on
Human Health
 Chronic: gradual deterioration of a
variety of physiological functions over
a period of years
 Acute: life-threatening reactions
within a period of hours or days
 Carcinogenic: cancer-causing
Impacts of Air Pollutants on
Human Health
 The Respiratory System
 Chronic Bronchitis and Asthma
 Lung Cancer
 Brain
 Birth defects, retardation, & nervous system
disorders
 Short- & Long-term memory loss
 Brain Cancer
 Filtering Organs (Liver & Kidneys)
 Short-term disfunction
 Cancer
 Skin
 Overexposure to UV --> Cancer
The Respiratory System
Impacts of Air Pollutants on the
Environment
 Plants
 Necrotic: kills plant cells
 Chlorotic: destroys chlorophyll, reducing
photosynthesis
 Increases susceptibility to disease and
pests
Ozone is the most serious pollutant to Plants
Ozone Impact on Crop Yields
Impacts of Air Pollutants on the
Environment
 Forests
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Leaching of nutrients
Release of aluminum into solution
Rapid changes in soil chemistry
Reduced growth and diebacks of plants and
animals
Increased plant vulnerability to natural enemies
Increased soil erosion
Increased flooding
Increased sedimentation of waterways
Impacts of Air Pollutants on the
Environment
 Building Materials
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Loss of color
Oxidation
Corrosion
Decreased real estate values
Trends in Automobile Emissions
Bringing Air Pollution under
Control
 Clean Air Act identifies most
widespread pollutants: e.g.,
particulates, SO, CO, NO, lead =
criteria pollutants
 National Ambient Air Quality Standards
(NAAQS) set levels that protect
environmental and human health
Bringing Air Pollution under
Control
 NAAQS = national ambient air
quality standards (EPA)
 National Emission Standards for
Hazardous Air Pollutants set
national emission standards for
hazardous air pollutants
Control Strategies
 Command-and-control: regulate air
pollution so criteria pollutants remain
below primary standard level
 Lack of enforcement and compliance
 37% reduction of air pollutants
 Forced compliance with state
implementation plan (SIP)
Can you Match Control Strategies on
Right with Air Pollutants on Left?
 Particulates
 VOCs
 Automobile
emissions
 Acid rain
 Catalytic
converter
 Reasonably
available control
strategy (RACT)
 Scrubbers
 Coal washing
Title IV Clean Air Act 1990
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Reduce SO emissions 50% below 1980 levels
Improve methods of reducing SO emissions
Allow emissions allowances and trading
Emissions purchases
Reduce NO emissions
Industry’s Response to Title
IV
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Fuel switching
Scrubbers
Emissions allowance trading
Using low-sulfur coals
Reducing Emissions from Point Sources
Reducing Motor Vehicle Air
Pollution
Unresolved Issues
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Costs vs benefits of air pollution control
Status of “new source” review & enforcement
Improving fuel efficiency – hybrid cars
Improving mass transit systems
Reducing commuting distances
Should the EPA regulate CO2 as a pollutant?
 Research this question! Come prepared to discuss
your findings in class tomorrow!