1. What is Ozone? - Chemical Formula is O3
- Found in the Stratosphere (good) and Troposphere (bad).
- Stratosphere ozone protects Earth from the Sun’s ultraviolet radiation.

2. mesosphere
stratosphere
troposphere

4. Where is ? --

5. Electromagnetic Spectrum
BACK

6. 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

7. Dobson Units
- The Dobson unit measures Ozone thickness at
standard temperature and pressure.

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

12. The destructive chemistry:
Chemical Equations showing destruction by Chloroflurocarbons (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