1. mesosphere
stratosphere
T: Ozone Layer
troposphere

3. What is Ozone? Chemical Formula is O3
- Found in the Stratosphere (good) and Troposphere (bad).

4. Where is ? --

5. Why is Ozone important? Absorbs and reflects UV rays.
Protects you and all other life on earth from UV rays.
BACK

6. How is Ozone Measured?
- The Dobson unit measures Ozone thickness at
standard temperature and pressure.

7. The Hole in the Ozone layer
- Area over South Pole where ozone (O3) loss (called “depletion”) exceeds 50 %
Happens in Sept., Oct. and Nov. since 1980s

9. Jan. Feb. March April May June
July Aug Sept Oct Nov Dec.

12. The destructive chemistry:
Chloroflurocarbons (CFC) destroy the ozone.
Chemical Equation, destruction by CFC.
• CCl2 F + light ---> Cl + CClF2
• Cl + O > ClO O2
• ClO O ---> Cl + O2
Rowland and Molina
1974 paper
Nobel Prize 1995

13. Uses of CFCs. - Refrigerators, freezers: 15 % (FREON)
- Air conditioners in cars and homes: 20 %
- Aerosols: 15 %
- Foams: 24 %

15. Next
Rowland and Molina

16. Why is the Ozone Layer a success story?