OZONE DEPLETION

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OZONE DEPLETION

• IS IT A SERIOUS THREAT?

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The Problem

• An increase in Chlorofluorocarbons in the upper
  stratosphere will break down the existing ozone
  layer which protects life on earth from intense
  ultra violet rays.
• (review electromagnetic spectrum)

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Chlorofluorocarbons

• Used as
• coolants in air conditioners
• cleaners for electronic parts
• sterilants for hospital instruments
• fumigants for granaries
• building blocks for plastic foam

• Dream chemicals?
• CFCs discovered 1930s
• Chemically stable, odorless, nonflammable,
  nontoxic, and non-corrosive , cheap

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Chlorofluorocarbons

• Nightmare chemicals
• spray cans, leaky air conditioners and
  refrigeration equipment and plastic foam leaked
  CFCs into the environment

• CFCs rise into the stratosphere where under the
  influence of Ultra Violet light they release
  chlorine atoms which break down the ozone layer.

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CFCs are not the only ozone eaters

• Chemicals that release bromine such as halons and
  HBFCs (both used in fire extinguishers)
• Cleaning solvents such as carbon tetrachloride
  and methyl chloroform

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Purpose of the Ozone Layer?

• The thinner ozone layer allows more UV light to
  penetrate the atmosphere
• This leads to
• more sunburns
• cataracts (clouding of the lens)
• skin cancers
• reduced crop production
• lowered immune response
• phytoplankton disturbed (effect CO2 uptake?

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Types of skin cancer
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What is the evidence that the ozone layer is
depleted?
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Solutions to the problem

• Stop producing ozone depleting chemicals - safe
  substitutes can be found (even so it will take
  50 years to repair damage).