Chapter 17: Atmospheric Science and Air Pollutio

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Chapter 17 Atmospheric Science and Air Pollution
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Atmosphere
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• surrounds earth
• mostly of N2, O2, Ar
• today's altering molecules
• consist of CH4, O3, CO2
• made up of layers
• ozone layer

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Other Atmospheric Properties

• atmospheric pressure
• force per unit of area that air exerts on the
  surface of Earth
• declines with altitude
• atmospheric humidity
• ratio of water vapor contained in a given volume
  of air in relation to it's maximum amount
  possible
• the more humidity the hotter it seems

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Seasons
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• determined by the positioning in relation to the
  sun
• atmosphere absorbs 70 of the energy
• the shorter the distance, the more intense the
  sun rays
• solar radiation intensity is lower at the poles
  and higher at the equator
• tilting of the planet causes the seasons to occur

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Air Circulation

• known as convective
• circulation
• caused by differences in
• humidity and temperature
• warm air rises as it is less dense
• cold air descends becoming denser

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Weather Climate

• Weather specifies atmospheric conditions over
  short periods of time and related to relatively
  small areas
• Climate describes patterns of atmospheric
  conditions across large regions and over long
  periods of time

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Weather
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• depends on the fronts
• cold? thunderstorms
• warm? light rain
• affected by the pressure
• systems
• high? fair to dry weather
• low? results in clouds and precipitation

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Thermal Inversion

• cooler air appears under warmer air
• prevents normal convective circulation to occur
• pollution is trapped under the inversion layer
  creating health problems like asthma
• killer smog in London
• asthma in San Joaquin valley

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Global Climate Patterns

• Hadley cells between equator and 30º
• heavy rain at the equator
• arid at 30º

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Global Climate Patterns

• Ferrer cells and polar cells lift air creating
  rain at 60º

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Wind Patterns

• caused by the interaction of Hadley and Ferrer
  cells and Earth's rotation
• Coriolis effect winds are curved

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Outdoor Air Pollution

• air pollutants
• natural sources
• human made sources

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Natural Pollutants

• we have no control, occur naturally
• volcano eruptions
• Mt. Pinatubo
• produces particles
• circle the globe and
• remain in suspension
• for months
• acid rain
• affect temperature

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Natural Pollutants

• dust storms

Dallas dust storm 2007
Texas dust storm 1930's
www.panoramio.com
Arthur Rothstein, photographer, April, 1936.
(Library of Congress)
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Natural Pollutants

• Fires
• soot and gases
• fuel buildup
• slash-and-burn
• in tropics
• El Niño

2000
www.gsfc.nasa.gov
LA
TX
T
Gulf Coast
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Human Created Outdoor Pollution

• primary pollutants
• emitted directly to the troposphere
• can be harmful to the environment
• can form chemicals harmful to the environment
• secondary pollutants
• react with constituents of the atmosphere

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Clean Air Act

• 1970
• set stricter standards for air quality
• imposed limits to emissions
• funds for pollution control research
• 1990
• strengthen air quality standards
• emission trading program for sulphur dioxide
• other emission trading programs developed

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EPA Standards

• carbon monoxide (CO)
• sulphur dioxide (SO2)
• nitrogen dioxide (NO2)
• tropospheric ozone (O3)
• particulate matter
• lead (Pb)

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Carbon Monoxide

• colorless
• odorless
• incomplete combustion
• in the U.S. 78 of it comes from vehicles
• small concentrations can be lethal to most living
  organisms

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Sulphur Dioxide

• colorless
• pungent odor
• power plants of coal
• once in the atmosphere SO2 reacts forming SO3 and
  later forming H2SO4
• H2SO4 forms acid rain

London 1952
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Nitrogen Oxides
www.epa.gov
Los Angeles

• contributes to smog
• NO2 is foul smelling, redish brown gas
• NOx cause acid rain
• product of combustion engines
• vehicles produce 50 of the U.S. NOX
• electricity production and industry the rest

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Ozone

• product of sunlight heat NOX carbon
  chemicals
• health risk because of its instability? O2
  Oxygen ion
• oxygen ion can cause tissue damage
• tissue damage can cause respiratory problems

www.epa.gov
Los Angeles
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Particulate Matter

• particles suspended in air
• primary pollutants ? dust and soot
• secondary pollutants ? sulphates and nitrates
• can damage respiratory tissues
• wind-blown result of human activities

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Lead

• particulate matter
• enters food chain
• can cause nervous system malfunction
• present in gasoline to improve performance
• industrialized nations phased out leaded gasoline
• industrial metal smelting is the problem now

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VOCs

• volatile organic compounds
• hydrocarbons
• methane forms part of natural gas
• propane used as portable fuel
• butane used in portable lighters
• octane component of gasoline

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Pollutants in the U.S.

• 2006
• 137 trillion tons
• EPA data

www.epa.gov
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Pollution Decreased since 1970

• emissions declined 53 since 1970
• cleaner burning vehicles
• catalytic converter
• clean coal technology
• baghouse filters
• electrostatic precipitators
• scrubbers
• phase-out of lead in gasoline

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Toxic Pollutants

• 188 toxic pollutants identified by the Clean Air
  Act in 1990
• effects on people
• cancer
• reproductive defects
• neurological problems
• developmental problems
• affect the immune system
• respiratory diseases

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Policy Bush Administration

• elimination of new source review of 1977
• new pollution targets
• retrofitting aging plants with new technologies
• industry protested too costly
• Bush Administration exempted older plants
• allowed installing only "the best available"
  technology IF they ever upgraded the plant
• Clear Skies (stopped by the Senate in 2005)
• from command-and-control to a market-based
  cap-and-trade

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Smog

• fogs polluted by smoke smog
• industrial smog
• photochemical smog

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Industrial smog
London 1952

• gray-air smog
• coal or oil burning
• CO, CO2, soot
• mercury and sulfur in the carbon sample
• sulfur reacts forming SO2
• sulphuric acid
• ammonium sulphate
• Problems today China, India, Eastern Europe

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Photochemical smog

• requires light
• brown-air smog
• ozone
• NOx
• VOCs
• irritates eyes, nose, throat
• car inspections
• reduction of vehicles driven per day
• allow certain cars to drive certain days of the
  week
• promote mass transit

Houston 2000
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Problems at Rural Areas

• airborne pesticides
• industrial pollutants from cities, factories and
  power plants migrate
• methane from cattle (18)
• feedlots
• CH4, dust, NH4, SOx
• can cause respiratory problems

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Industrialization
China

• is worsen air quality
• caused by factories and power plants
• emissions are released with little effort to
  control pollution
• China India have 58 of premature deaths
  worldwide (WHO)
• Asian brown cloud
• reduces sunlight
• decreases productivity

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Synthetic Chemicals

• CFCs (chlorofluorocarbons)
• affects the ozone layer
• creating the ozone hole in Antarctica
• increases UV radiation
• leads to more skin cancer
• ecological effects still unknown
• hole in the arctic

Arctic hole
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Montreal Protocol of 1987

• addressed ozone depletion
• 180 nations agreed to cut CFCs production in half
• production and use has dropped by 95
• alternative chemicals
• CFCs take very long to brake down
• www.epa.gov/cppd

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Acid Deposition

• originates with the NOx and SOx
• forms of precipitation known as acid rain
• fog
• dry particles
• pollutants react with water, O2, oxidants
• produce compounds of low pH (acids)
• these are suspended in the troposphere before
  falling as rain
• can cause political bickering

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Acid Rain

• alters soil composition because
• leaches chemicals from the soil
• harming plants and soil organisms
• also mobilizes toxic chemicals
• converts them to soluble forms
• affects agriculture
• affect lakes and rivers
• causing high mortality in fishes and amphibians

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Acid Rain

• erosion of buildings
• corrodes cars
• erosion of statues and obelisks
• has not been reduced as expected in 1990
• more reduction of sulphur oxides and nitrogen
  oxides need to occur

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Indoor Air Pollution

• higher concentration of pollutants indoor than
  outdoor
• workplaces, schools, homes
• volatile chemicals in the air
• insecticides
• cleaning fluids
• plastics
• chemically treated wood

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Other Sources

• wood burning
• chimneys
• cooking
• tobacco smoking
• radon

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Indoor VOC Pollution

• perfumes
• paints
• plastics
• oils/candles
• cleaning fluids
• adhesives (glues)
• pesticides and insecticides
• ink (fax, photocopiers, printers)
• color films

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Living Organisms also Pollute

• dust mites
• animal dander
• mold
• bacteria
• THE END