Ozone Depletion

> UV is a highly energetic electromagnetic radiation from the Sun that is able to produce material damage to matter by the creation of free radicals (charged atoms)

> this damaging radiation does have positive biological qualities in small doses

> in larger doses UV can cause skin cancer and eye cataracts as well as leaf damage

> plankton and coral polyps are sensitive to the damage of UV radiation

> skin cancer is now an epidemic 25% of Australians will get skin cancer!

> the OZONE layer is a diffuse layer of low concentration O₃  in the stratosphere that
absorbs UV energy

> ozone is made when oxygen absorbs UV energy , the protective ozone layer (required for protecting terrestrial life) did not exist until plants oxidized the atmosphere!

 

> Chlorine (Cl) Bromine (Br) Fluorine (Fl), all halogens, catalyze the breakdown of ozone

> halogens are lofted to the stratosphere as components of CFCs and allied molecules

> CFC compounds were made first in the 1930's as a miracle molecule that could replace the toxic materials used in refrigerators that were harming people

> CFC's  are nontoxic stable

> chlorofluorocarbons are used in aerosol cans, electronics parts cleaners, air conditioners and refrigerators and select pesticides
> many of these are being replaced
> because the halogens catalyze the breakdown of ozone it can remain in action for up to 75 Y before falling to Earth

> the main producer of CFC's Dupont knew about the problem years before it was public ........... they now profit as the producer of the substitute chemical

> a hole forms over the Antarctic because the winds are circumpolar in the winter (our summer) locking up CFCs and in the summer the stratosphere is cold and humid enough to create ice crystals that act as a reaction surface that increases the rate of ozone destruction

> satellite imaging shows that the ozone layer is stabilizing but it will take many decades before it heals completely rocket fuel contains chlorine that destroys ozone