troposphere

stratosphere

mesosphere

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.

Where is

?

Electromagnetic SpectrumElectromagnetic Spectrum

BACK

The Hole in the Ozone layerThe Hole in the Ozone layer• Area over South Pole where ozone (OArea over South Pole where ozone (O33) )

loss (called “depletion”) exceeds 50 % loss (called “depletion”) exceeds 50 % • Happens every Sept., Oct. Nov. since 1980sHappens every Sept., Oct. Nov. since 1980s

Dobson Units The Dobson unit measures Ozone thickness at standard temperatureand pressure.

Jan. Feb. March April May June

July Aug. Sept. Oct. Nov. Dec.

The destructive chemistry:The destructive chemistry:

• CClCCl2 2 FF22 + light ---> Cl + CClF+ light ---> Cl + CClF22

• Cl + OCl + O3 3 ---> ClO + O---> ClO + O22

• ClO + O ---> Cl + OClO + O ---> Cl + O22

You do not need to write this down.

Rowland and MolinaRowland and Molina1974 paper1974 paperNobel Prize 1995Nobel Prize 1995

Uses of CFCs.Uses of CFCs.

• Refrigerators, freezers: 15 % (FREON)Refrigerators, freezers: 15 % (FREON)

• Air conditioners in cars and homes: 20 Air conditioners in cars and homes: 20 %%

• Aerosols: 15 %Aerosols: 15 %

• Foams: 24 %Foams: 24 %

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