Card Set Information

2012-03-18 01:24:00
Environmental Health

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  1. Earth-Atmsophere System
    • A closed system- every material that goes into the air can circulate and change in form, but remains within the system.
    • Radiation is all that is exchanged
    • The solution to pollution is NOT dilution
  2. Composition of Dry Air
    • 78% Nitrogen
    • 21% Oxygen
    • 0.9% Argon
    • 0.03% Carbon Dioxide
    • Trace amounts of: Neon, Helium, Krypton, Xenon, Hydrogen, Methane, and Nitrous Oxide
  3. Regions of the Atmosphere
    • Troposphere- From sea level to 8 miles above the earth
    • Stratosphere- Site of Ozone Layer
    • Mesosphere- Above the stratosphere
    • Thermosphere- Inverted temperature effect
  4. Atmosphere Functions
    • Protects life on Earth from the sun's harmful radiation
    • Acts as a buffer to control temperatures-earth doesn't endure extreme heat during the day or extreme cold at night
    • Provedes CO2 and O2 for life on Earth
  5. Sources of Depletion of Ozone Layer
    • Chlorofluorocarbons (CFCs)- Refrigerants and propellants in aerosol cans
    • Halons(Br-, Cl-, F-, I-) Used as fire retardants, in dry cleaning, etc
    • NOx- high temperature combustion products- from jets, car exhaust, coal burning, etc.
    • Bromine 50X more efficient at destroying ozone than
    • chlorine. All halons contain bromine.
  6. Ozone Depletion
    • CFC products banned in the US in 1978
    • 1981 scientists discovered a hole in the ozone layer- it represented a 40% decline in ozone concentrations
    • By 2008 it was 29 million square miles (the size of N. America)
    • Current thinking is that increasing incidence of skin cancer is a result of ozone depletion
  7. Montreal Protocol
    • 1987 Twenty- Nine nations signed an international accord to control the chemical most responsible for ozone depletion
    • called for 50% CFC production by 2000
    • 23 years after Montreal the annual hole over Antartica shows no sign of recovery, it is not getting bigger either
  8. The Greenhouse Effect
    • Absorption of infrared ground radiation by CO2 and its re-radiation back toward the earth helps to maintain the average global temperatures
    • As CO2 increases, more infrared radiation is absorbed and trapped. Over time the global temperature rises.
  9. Global Warming
    • CO2 Increases have been somewhat managed by being incorporated into carbonate rock in the oceans or fixed by green plants
    • Approx. 50% of CO2 is still being taken care of this way- however ocean sequestration is at capacity. Theis process is highly temperature dependent. Rising temperature will release CO2 increasing global warming dramatically in the process
  10. Other Greenhouse Gases
    • Methane- very potent and increasing at a 0.6% yearly rate. Very hard to control because there are so many sources: rice cultivation, cattle, termites, landfills, coal/gas production, and burning
    • Nitrous Oxide- still fairly limited, but levels are rising
    • Halocarbons- Very potent
  11. Impacts of Global Warming
    • Diminishing crop yields due to: shifting rainfall patterns, higher temps, more weed growth, UVa and UVb damage
    • Loss of biodiversity
    • Rising Sea Levels
    • Human Ilness
  12. Effects of Global Warming Cont
    • Global Dimming
    • Phytoplankton Losses
    • Species extinction
  13. Major CO2 Emitting countries
    • China
    • US
    • Russia
    • Japan
    • India
  14. Indicators of Global Warming
    • 0.6 dgree temp rise already documented. 5-8 deg. increase predicted by 2050.
    • Spring in North arrives one week earlier than int he 1970's, fall alsts 3-5 days longer
    • Mountain glaciers are melting, ocean water and air temps rising in the norht
    • Sea Ice is melting- massive ice sheets gone, species in peril, distribution patterns of plants/animals are shifting
  15. Melting polar ice
    According to NASA the permanent artic ice is melting 3X faster than previously thought due to global warming. At this rate the polar ice cap will be gone by the end of this century
  16. Species headed for extinction
    20% of all bird species may be extinct by 2100 due to global warming related habitat changes
  17. Stopping global warming
    • Mandatory emissions reductions by imporoved efficiency:
    • A 45 mpg auto std.=40% drop in CO2 emissions
    • Efficiency standards for appliances, tools, homes
    • Tax Credits for more efficient industries
  18. Kyoto Accord
    • Coutnries asked to sign agreement to reduce greenhosue gases
    • Developed countries 5% below 1990 CO2 levels
    • Allows tading pollution credits
    • Last Kyoto talks called for greenhosue gas reduction of 6% in Canada and 7% in the USA
    • Bush Administration rejected Kyoto saying cutting emissions is not in the US interest
  19. Ethanol
    • It takes 4 gal water to produce 1 gal ethanol
    • Ethanol plants use 2 million gal water/day, also they stink and foul groudnwater
    • Every million acres corn planted sends 16 million lbs of nitrogen runoff into rivers/streams
    • Water resources already stressed to breaking point
  20. Air Pollution
    60% of Americans live where air pollution reaches "dangerous" levels
  21. Most Polluted US Cities
    • Atlanta GA
    • Bakersfield CA
    • Philadelphia PA
    • Raleigh NC
    • Knoxville TN
  22. Air Pollution Disasters
    • Mt. Tambora, Indonesia- 1815: Largest eruption in recorded history. 70,000 killed
    • Mt. Pinatubo- 1991: ejected 20 million tons of SO2 and aerosols into the stratosphere.
    • Kuwait/Iraqi Oil Field Fires- 1990: 700 wells set ablaze. 6 million barrels burned daily. Fires took over a year to extinguish.
  23. Federal Legislation
    • Clean Air Act (1936)
    • Clean Air Act Amendments (1970) set standards for criteria pollutants
    • Identified seven Hazardous Air Pollutants (HAPS and declared "no standard was applicable for these)
  24. Harzardous Air Pollutants
    • beryllium
    • mercury
    • vinyl chloride
    • asbestos
    • benzene
    • radionuclides
    • arsenic
  25. Clean Air Act Amendments (1990)
    • Established a safety standard for acceptable risk of cancer of 1 in 100,000
    • 189 substances listed as Harzardous Air Pollutants
    • The sources of the HAPS must reduce emissions by 2003
  26. Air Pollution Faces
    • Pollution by coal fired power plants causes 30,000 premature deaths /yr
    • Addition they are responsible for deadly smog, soot, global warming, fish toxicity from mercury and lead, and poisoning of estuaries
    • In polluted cities the average life is cut short by 1-2
    • CDC: 65,000 Americans/yr die premautrely from air polltion related cardio respiratory stress
  27. Sources of Indoor Pollution
    • Gases
    • VOCs
    • Reactive Chemicals
    • Radon
    • Environmental particulates
  28. Health Problems associated with Indoor Air Pollution
    • Asthma-increasing in prevalence and severity, nationally and internationally
    • Sick Building Syndrome- Symptoms vary
    • Multiple chemcial sensitivity
  29. Reduing Indoor Air Pollution
    • Ventilation is an effective way to reduce indoor concentrations of contaminants
    • Natural ventilation
    • Mechanical Ventilation
  30. Vulnerable Populations
    • The Elderly: Aging- chronic illness & increased susceptibility to infection diseases or extreme heat
    • Low Income Individuals: Povery and heat-related illness/deaths
    • Children: Poverty, lack of access to medical care. Size, behavior, and susceptibility to toxins