The Ozone Layer
"[W]e have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we may have. Each of us has to decide what the right balance is between being effective and being honest."

-Stephen Schneider, proponent of the theory that CFCs are depleting the ozone
"We are facing a danger as big as humanity has ever faced."

-Dr. Mostafa Tolba, Former Executive Director of the United Nations Environment Programme, April, 1992, Montreal Protocol talks in Geneva.
Some Statistics...
~The amount of ozone  over Antarctica has decreased to aproximately half of previous state
~Globally, the ozone in the ozone layer has decreased 3-5 percent
~About half of the chlorine and bromine present in the stratosphere is there due to human activities
~For every 1% decrease in the concentration of ozone in the stratosphere, there would be a 5% increase in number of nonmalignant skin cancers each year in US- an additional 10,000 to 20,000 victims above present fugures.
~One atom of chlorine can act as a catalyst to decompose as many as 100,000 molecules of ozone
Chapman Reactions
With Increasing Altitude:

< Slower reaction

< Faster reaction

Normally, greater amounts of UV rays mean greater concentrations of ozone.
O2 + uv  ->  O + O
O + O2  ->  O3

O3 + uv  ->  O2 + O
O + O2  ->  O3

O + O3 ->  O2 + O2
Why Antarctica?
~Polar vortexes- Extremely cold column of air that forms during the winter when there is no sun. Very strong winds circle around the column, isolating the air inside.
~When temperature goes below -80 C, clouds form out of nitiric acid trihydrate.
~Chemicals act as catalysts to ozone reaction
Causes and Consequences of the Depletion
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