Chapter 20, sections1-4, 6-7 Atmosphere and Outdoor Air Pollution

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Chapter 20, sections1-4, 6-7Atmosphere and
Outdoor Air Pollution
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Natural features that influence air
characteristics

• Sun incoming radiation
• Structure of the atmosphere
• Hydrologic cycle - precipitation
• Climate wind currents, latitude
• Ocean
• Natural pollutants

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The atmosphere

• Atmosphere the thin layer of gases that
  surrounds Earth
• Absorbs radiation and moderates climate
• Transports and recycles water and nutrients
• 78 nitrogen gas, 21 oxygen gas, 1 other gases
• Its four layers differ in temperature, density
  and composition
• Minute concentrations of permanent (remain at
  stable concentrations) and variable gases
  (varying concentrations)
• Human activity is changing the amounts of some
  gases

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Review The atmospheres four layers
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Natural sources pollute dust storms

• Dust storms Hundreds of millions of tons of
  dust are blown westward across the Atlantic Ocean
  by trade winds every year
• From Africa to the Americas
• Unsustainable farming and grazing, erosion and
  desertification

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Natural sources pollute volcanoes

• Release large quantities of particulate matter,
  sulfur dioxide other gases
• Can remain for months or years
• Aerosols very fine liquid droplets or solid
  particles aloft in the atmosphere reflect
  sunlight back into space and cool the atmosphere
  and surface

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Natural sources pollute fires

• Pollutes atmosphere with soot and gases
• Over 60 million ha of forests and grasslands burn
  per year
• Severe fires are caused by human interaction
• Cleared forests, harsh droughts, and climate
  change (El Niño)

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Humans significantly contribute to outdoor air
pollution

• Air pollution can come from mobile or stationary
  sources
• Point Sources specific spots where large
  quantities of pollutants are discharged (power
  plants and factories)
• Nonpoint Sources more diffuse, consisting of
  many small sources (automobiles)
• Primary Pollutants directly harmful and can
  react to form harmful substances (soot and carbon
  dioxide)
• Secondary Pollutants form when primary
  pollutants interact or react with constituents or
  components of the atmosphere (tropospheric ozone
  and sulfuric acid)

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Primary Pollutants
CO
CO2
Secondary Pollutants
SO2
NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended particles
H2O2
O3
PANs
Most
and
salts
Sources
Natural
Stationary
Mobile
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Table 20-1 Major Classes of Air Pollutants
Class Carbon oxides Sulfur oxides Nitrogen
oxides Volatile organic compounds
(VOCs) Suspended particulate matter
(SPM) Photochemical oxidants Radioactive
substances Hazardous air pollutants (HAPs),
which cause health effects such as cancer, birth
defects, and nervous system problems
Examples Carbon monoxide (CO) and carbon dioxide
(CO2) Sulfur dioxide (SO2) and sulfur trioxide
(SO3) Nitric oxide (NO), nitrogen dioxide (NO2),
nitrous oxide (N2O) (NO and NO2 often are lumped
together and labeled NOx) Methane (CH4), propane
(C3H8), chlorofluorocarbons (CFCs) Solid
particles (dust, soot, asbestos, lead, nitrate,
and sulfate salts), liquid droplets (sulfuric
acid, PCBs, dioxins, and pesticides) Ozone (O3),
peroxyacyl nitrates (PANs), hydrogen
peroxide (H2O2), aldehydes Radon-222,
iodine-131, strontium-90, plutonium-239 (Table
3-1, p. 49) Carbon tetrachloride (CCl4), methyl
chloride (CH3Cl), chloroform (CHCl3), benzene
(C6H6), ethylene dibromide (C2H2Br2),
formaldehyde (CH2O2)
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Effects of air pollution on human body

• Respiratory system natural protection
• Nose mucus, hair to filter air
• Respiratory tract lined with cilia to move
  particles to throat (cough or swallow)

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Effects of air pollution on human body

• Effects on respiratory system
• Irritation of respiratory system
• Bronchitis
• Allergic reactions
• Asthma muscle spasms in bronchial walls
• Emphysema permanent damage to lungs
• Cancer

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Effects of air pollution on human body

• Other effects
• Cardiovascular
• Neurological
• Teratogenic effects related to normal
  development of fetus and child
• Cancer

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The EPA sets standards

• Environmental Protection Agency (EPA) sets
  nationwide standards for emissions of toxic
  pollutants
• States monitor air quality and develop,
  implement, and enforce regulations within their
  borders
• If a states plans for implementation are not
  adequate, the EPA can take over enforcement
• NAAQS National Ambient Air Quality Standards,
  six criteria air pollutants are used
• Criteria air pollutants pollutants judged to
  pose especially great threats to human health

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List of Criteria Pollutants

• Carbon monoxide (CO)
• Nitrogen dioxide (NO2)
• Sulfur dioxide (SO2)
• Suspended particulate matter
• Tropospheric ozone (O3)
• Lead

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Table 20-2 Major Outdoor Air Pollutants
CARBON MONOXIDE (CO) Description Colorless,
odorless gas that is poisonous to air-breathing
animals forms during the incomplete combustion
of carbon-containing fuels (2 C O2 2
CO). Major human sources Cigarette smoking (p.
409), incomplete burning of fossil fuels. About
77 (95 in cities)comes from motor vehicle
exhaust. Health effects Reacts with hemoglobin
in red blood cells and reduces the ability of
blood to bring oxygen to body cells and tissues.
This impairs perception and thinking slows
reflexes causes headaches, drowsiness,
dizziness, and nausea can trigger heart attacks
and angina damages the development of fetuses
and young children and aggravates chronic
bronchitis, emphysema, and anemia. At high levels
it causes collapse, coma, irreversible brain cell
damage, and death.
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Table 20-2Page 438
Table 20-2 Major Outdoor Air Pollutants
NITROGEN DIOXIDE (NO2) Description
Reddish-brown irritating gas that gives
photochemical smog its brownish color in the
atmosphere can be converted to nitric acid
(HNO3), a major component of acid
deposition. Major human sources Fossil fuel
burning in motor vehicles (49) and power and
industrial plants (49). Health effects Lung
irritation and damage aggravates asthma and
chronic bronchitis increases susceptibility to
respiratory infections such as the flu and common
colds (especially in young children and older
adults). Environmental effects Reduces
visibility acid deposition of HNO3 can damage
trees, soils, and aquatic life in
lakes. Property damage HNO3 can corrode metals
and eat away stone on buildings, statues, and
monuments NO2 can damage fabrics.
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Table 20-2Page 438
Table 20-2 Major Outdoor Air Pollutants
SULFUR DIOXIDE (SO2) Description Colorless,
irritating forms mostly from the combustion of
sulfur containing fossil fuels such as coal and
oil (S O2 SO2) in the atmosphere can be
converted to sulfuric acid (H2SO4), a major
component of acid deposition. Major human
sources Coal burning in power plants (88) and
industrial processes (10). Health effects
Breathing problems for healthy people
restriction of airways in people with asthma
chronic exposure can cause a permanent condition
similar to bronchitis. According to the WHO, at
least 625 million people are exposed to unsafe
levels of sulfur dioxide from fossil fuel
burning. Environmental effects Reduces
visibility acid deposition of H2SO4 can damage
trees, soils, and aquatic life in
lakes. Property damage SO2 and H2SO4 can
corrode metals and eat away stone on buildings,
statues, and monuments SO2 can damage paint,
paper, and leather.
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Table 20-2Page 438
Table 20-2 Major Outdoor Air Pollutants
SUSPENDED PARTICULATE MATTER (SPM) Description
Variety of particles and droplets (aerosols)
small and light enough to remain suspended in
atmosphere for short periods (large particles) to
long periods (small particles Figure 20-6, p.
441) cause smoke, dust, and haze. Major human
sources Burning coal in power and industrial
plants (40), burning diesel and other fuels in
vehicles (17), agriculture (plowing, burning off
fields), unpaved roads, construction. Health
effects Nose and throat irritation, lung damage,
and bronchitis aggravates bronchitis and asthma
shortens life toxic particulates (such as lead,
cadmium, PCBs, and dioxins) can cause mutations,
reproductive problems, cancer. Environmental
effects Reduces visibility acid deposition of
H2SO4 droplets can damage trees, soils, and
aquatic life in lakes. Property damage Corrodes
metal soils and discolors buildings, clothes,
fabrics, and paints.
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Table 20-2Page 438
Table 20-2 Major Outdoor Air Pollutants
TROPOSPHERIC OZONE (O3) Description Highly
reactive, irritating gas with an unpleasant odor
that forms in the troposphere as a major
component of photochemical smog Major human
sources Chemical reaction with volatile organic
compounds (VOCs, emitted mostly by cars and
industries) and nitrogen oxides to form
photochemical smog Health effects Breathing
problems coughing eye, nose, and throat
irritation aggravates chronic diseases such as
asthma, bronchitis, emphysema, and heart disease
reduces resistance to colds and pneumonia may
speed up lung tissue aging. Environmental
effects Ozone can damage plants and trees smog
can reduce visibility. Property damage Damages
rubber, fabrics, and paints.
NOx VOCs heat light ? ozone
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Table 20-2Page 438
Table 20-2 Major Outdoor Air Pollutants
LEAD Description Solid toxic metal and its
compounds, emitted into the atmosphere as
particulate matter. Major human sources Paint
old houses), smelters (metal refineries), lead
manufacture, storage batteries, leaded gasoline
(being phased out in developed countries). Health
effects Accumulates in the body brain and
other nervous system damage and mental
retardation (especially in children) digestive
and other health problems some lead-containing
chemicals cause cancer in test animals. Environme
ntal effects Can harm wildlife.
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U.S. air pollution

• In 2006, the U.S. emitted 137 million tons of the
  six major pollutants

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Air Quality Indexhttp//airnow.gov/index.cfm?acti
onairnow.currentconditions
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Have you seen this before?

• Orange ozone alert issued for Friday
• Posted by Press-Register Staff June 21, 2007 411
  PM
• Categories Breaking News
• The U.S. Environmental Protection Agency issued
  an orange alert for Friday, meaning that outdoor
  conditions are expected to be unhealthy for
  sensitive groups.
• An orange alert indicates that high levels of
  ozone, a type of air pollution, could have a
  negative impact on the health of active children
  and adults, as well as people with respiratory
  diseases. Prolonged outdoor exertion should be
  limited, the EPA says.

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Areas in the U.S. fail air quality standards
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Toxic substances also pollute

• Hazardous air pollutants (HAPs) substances
  known to cause cancer reproductive defects or
  neurological, development, immune system, or
  respiratory problems
• Some are produced naturally hydrogen sulfide
• Most are produced by humans smelting, sewage
  treatment, industry
• Not monitored as closely as the six criteria
  pollutants
• Monitoring is improving

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Examples of toxic air pollutants

• Mercury
• Benzene
• Formaldehyde
• Heptachlor
• PCBs (polychlorinated biphenyls)
• Naphthalene

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Burning fossil fuels produces industrial smog

• Smog unhealthy mixtures of air pollutants over
  urban areas
• Industrial (gray air) smog industries burn coal
  or oil
• Occurs in cooler, hilly areas
• Government regulations in developed countries
  reduced smog
• Coal-burning industrializing countries face
  significant health risks

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Photochemical (brown air) smog

• Produced by a series of reactions
• Hot, sunny cities surrounded by mountains
• Light-driven reactions of primary pollutants and
  normal atmospheric compounds
• Morning traffic exhaust releases pollutants
• Irritates eyes, noses, and throats
• Vehicle inspection programs in the U.S. have
  decreased smog

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Industrial smog
Photochemical smog

• 17.16

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Special problem with outdoor air pollution

• Temperature inversion when the air above is
  warmer than the air below and pollution can be
  trapped

Brisbane, Australia
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• Birmingham is located in a valley and sometimes
  has a lot of smog trapped in the atmosphere due
  to temperature inversions, especially in summer

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Industrializing nations face increasing pollution

• Outdoor pollution is increasing
• Factories and power plants do not control
  emissions
• Citizens burn traditional fuels (wood and
  charcoal)
• China has the worlds worst air pollution
• 80 of Chinese cities have emissions above the
  safety threshold
• Asian brown cloud a 2-mile thick layer of
  pollution that reduces sunlight, affects climate,
  decreases productivity, and kills thousands each
  year

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Acid Deposition

• Normal precipitation is slightly acidic (pH 5.5)
  because CO2 combines with water in the air to
  form carbonic acid
• When sulfur dioxide and nitrogen oxides are
  present, they can react with water to form
  sulfuric acid (H2SO4) and nitric acid (HNO3)
• Two things can then happen
• wet deposition acids return to earth in
  precipitation (acid rain)
• dry deposition acids form sulfate or nitrate
  salts and return to earth as particles

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Wind
Transformation to sulfuric acid (H2SO4) and
nitric acid (HNO3)
Windborne ammonia gas and particles of cultivated
soil 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)
Dry acid deposition (sulfur dioxide gas and
particles of sulfate and nitrate salts)
Sulfur dioxide (SO2) and NO
Acid fog
Farm
Lakes in shallow soil low in limestone become acid
ic
Ocean
Lakes in deep soil high in limestone are buffered
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Effects of acid deposition

• Nutrients are leached from topsoil
• Soil chemistry is changed
• Metal ions (aluminum, zinc, etc.) are converted
  into soluble forms that pollute water
• Widespread tree mortality
• Affects surface water and kills fish
• Damages agricultural crops
• Erodes stone buildings, corrodes cars, erases
  writing on tombstones

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Emission
Acid deposition
SO2 H2O2 PANs
NOX O3 Others
Increased Susceptibility to drought, extreme
cold, insects, mosses, and disease organisms
Reduced photosynthesis and growth
Direct damage to leaves and bark
Soil acidification
Tree death
Reduced nutrient and water uptake
Leaching of Soil nutrients
Root damage
Release of toxic metal icons
Acid
Groundwater
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Acid Deposition Effects

• Any precipitation under pH 5 is considered acidic
  this can have negative effects on ecosystems,
  especially aquatic ones
• Eggs and young are usually affected more than
  adults (most fish eggs will not hatch at pH 5 or
  below)
• Acid shock sudden change
• in pH of aquatic ecosystem
• that occurs with influx of
• rainfall, snow melt

Chart above shows pH at which different species
can survive (frogs can survive in a pH of 4.0 but
trout cannot survive below pH 5.0)
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Acid Deposition Effects

• Some areas have geology that provides a buffering
  effect (resists change in pH), others do not and
  are more susceptible to damage from acid
  deposition

High alkalinity lakes in areas with
limestone Low alkalinity lakes in areas with
granite
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Acid Deposition Effects
Entire food chains can be affected In one case
of acid rain pollution in the Netherlands, acid
rain caused loss of calcium from the soil As a
result, snails that depended on soil calcium for
their shells could not live and birds that fed on
snails had weakened egg shells, lower
reproductive success
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Acid Deposition Effects
Trees are not usually killed directly by
precipitation with low pH Instead, leaves are
damaged, soil chemistry changes, overall health
of trees is compromised, more susceptible to
disease and stress
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pH of precipitation in the U.S.

• Many regions of acidification are downwind of
  major sources of pollution

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Potential problem areas because of sensitive soils
Potential problem areas because of air
pollution emissions leading to acid deposition
Current problem areas (including lakes and rivers)
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Air pollution has decreased since 1970

• Total emissions of the six monitored pollutants
  have declined
• Despite increased population, energy consumption,
  miles traveled, and gross domestic product

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Legislation addresses pollution

• Congress passed a series of laws starting in 1955
• The Clean Air Act of 1970
• Sets standards for air quality, limits on
  emissions
• Provides funds for pollution-control research
• Allows citizens to sue parties violating the
  standards
• The Clean Air Act of 1990
• Strengthens standards for auto emissions, toxic
  air pollutants, acidic deposition, stratospheric
  ozone depletion
• Introduced emissions trading

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Reasons for the decline in U.S. pollution

• Industry
• Taller smokestacks put pollution higher into
  atmosphere for dispersal
• Scrubbers technologies that chemically convert
  or physically remove pollutants before they leave
  the smokestacks
• The one pictured here is called a wet scrubber
  because it uses water to remove pollutants from
  emissions

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Another scrubber Electrostatic Precipitator
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Reasons for the decline in U.S. pollution

• 1. Industry, continued
• Permit-trading programs cap and trade
• Clean coal technologies

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Reasons for the decline in U.S. pollution

• Vehicles
• Catalytic converters decrease carbon monoxide
• Phaseout of leaded gasoline
• Zero emission vehicles (ZEV)
• Hybrid technology increase fuel efficiency
• Increase fuel efficiency standards for cars
  (improving in developed countries, not as much in
  developing)
• Cash for clunkers campaign

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Recent policies have been contentious

• New source reviews old utility plants have to
  install the best available technology when
  upgrading
• The Bush administration proposed abolishing this
  requirement and dropped lawsuits against
  violators
• Clear Skies Initiative controversial
  legislation proposed by G.W.H. Bush in 2003 that
  dealt with air pollution never enacted

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Acid deposition has not been greatly reduced

• New technologies such as scrubbers have helped
• SO2 emissions are lower
• But, NOx emissions are higher
• Acid depositions effects are worse than
  predicted
• The Clean Air Act cannot restore ecosystems
• More must be done to control acid deposition

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Energy efficiency

• Using less energy in homes and businesses means
  reduced energy needs from current power plants
  and building fewer power plants (result is less
  air pollution)
• Energy-saving light bulbs
• Energy-saving building design (LEED)
• Alternative clean fuels
• MORE TO COME IN CHAPTER ON ENERGY!!!

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What about Birmingham?

• Birminghams air quality has improved since the
  Clean Air Act was passed
• Bham has also lost a lot of the steel industry
  it used to have (heavy polluter)
• Nearby old coal powered plants continue to emit a
  lot of pollution (NOx, SO2 and mercury) that
  affects Bham
• Still has a major problem with ground level
  ozone, especially in summer (some areas failed to
  pass EPA standards for 25 years)
• Has virtually no mass transit, so a lot of
  pollution is due to transportation
• Some areas, generally poorer (e.g., north Bham),
  
• have more air pollution than others

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Steps to improve air quality in Birmingham

• Southern Environmental Law Center
• takes cases related to environment
• http//www.southernenvironment.org/cases/clean_air
  _for_the_birmingham_area

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