OZONE

 

I. Chemical Nature of OZONE

• Formed by lightning and smog production

 

O₂                         O^˜   + O^˜  

 

O ^˜  + O₂                         O₃   

 

II. The OZONE Layer

·        12 – 35 miles, in stratosphere

·        1^st line of defense against UV screens our 99% of UV

 

III. Destruction of the OZONE layer

·        “Hole” is actually a thinning (50% reduction)

 

Chlorine can destroy O₃   

·        Volcanic eruptions

·        Chlorofluorocarbons (CFC’s)

-       Cl released

-       Aerosols & Freon

 

Cl + O₃  O₂  + ClO

 

ClO + O^˜   O₂  + Cl

 

·        1 Cl atom can destroy 100,000 O₃ molecules

 

IV. Effects of O₃ depletion

·        6-12 % down # phytoplankton

·        down 1% O₃              up 1.3% UV

·        EPA predicts down 5% O₃

940,000 non fatal skin cancer

30,000 fatal skin cancer

 

V. What now?

·        Montreal Protocol (2000)

          Reduce CFC production