1. Ozone Layer O 3 Absorbs the sun’s UV radiation Stratosphere 20-50km above the Earth’s surface

2. Ultraviolet Radiation Good: Causes Vitamin D production in humans Bad: Causes skin cancer, cataracts, and mutations, blindness, sunburn.  Severe crop damage  Destroy microorganisms at bottom of food chain

3. Ozone Depletion Antarctic Ozone Hole http://ozonewatch.gsfc.nasa.gov/

4. The Chemistry CFC’s = Chlorofluorocarbons CFC’s in UV radiation release a Cl Cl + O 3  ClO + O 2 ClO + O  Cl + O 2 IT’S A CYCLE!!! US Banned CFC’s in many products in 1978

5. Montreal Protocol Complete Phaseout of CFC’s by 1996 Good Example of countries coming together for the benefit of the environment

6. Ozone depleting substances

7. Question: What does the hole in the ozone layer mean for us? What can we do to protect ourselves from UV radiation? GRAPH: How has the Antarctic Ozone Hole Changed over time???