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The Ozone Hole

The Ozone Hole. The Ozone Layer. Stratospheric ozone Block 95% harmful UV radiation. http://svs.gsfc.nasa.gov/goto?824. ODC: Ozone Depleting Chemicals. CFC’s: Chlorofluorocarbons Stable, odorless, nonflammable, nontoxic, noncorrosive Coolants, propellants, cleaners, fumigants, insulation

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The Ozone Hole

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  1. The Ozone Hole

  2. The Ozone Layer • Stratospheric ozone • Block 95% harmful UV radiation http://svs.gsfc.nasa.gov/goto?824

  3. ODC: Ozone Depleting Chemicals • CFC’s: Chlorofluorocarbons • Stable, odorless, nonflammable, nontoxic, noncorrosive • Coolants, propellants, cleaners, fumigants, insulation • Halons (bromine, fluorine) • Fire extinguishers • Solvents • Fumigants

  4. Rowland and Molina: Groundbreaking Study 1974 • CFC’s remain in troposphere (65 – 385 years) • CFC’s are heavier than air, but are carried to the stratosphere by convection and turbulence • CFC molecules break down with high energy input from UV radiation • Chlorine molecules break apart ozone http://svs.gsfc.nasa.gov/goto?825

  5. The Ozone Hole: Discovered 1984 • Ozone thinning, NOT ozone “hole” • Occurs over Antarctica during spring (Aug – Nov) http://svs.gsfc.nasa.gov/goto?3303

  6. Impacts of Ozone Depletion • Human Health • Skin cancer, sunburns, eye cataracts • Reduced primary productivity in the ocean (kills plankton, algae) • Impacts on food web and CO2 • Potential damage to food crops • Degradation of materials (paints and plastics)

  7. Management: The Montreal Protocol, 1987 • International agreement • Eliminate CFC production (goal) • By 1995 in developed nations • By 2000 in developing nations • Assessment of Effectiveness: • ODC’s will return to pre-1980 levels by 2050 • Ozone “hole” is shrinking!!!

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