HEALTH IMPLICATION OF THE OZONE LAYER
Approximately
90 per cent of all ozone is produced naturally in the stratosphere.
While ozone can be found through the entire atmosphere, the greatest
concentration occurs at an altitude of about 25
km. This band of ozone-rich air is known as the "ozone layer".
Ozone Depletion
Ozone
depletion is the term commonly used to describe the thinning of the
ozone layer in the stratosphere. Ozone depletion occurs when the natural
balance between the production and destruction of ozone in the
stratosphere is tipped in favour of destruction.
Health & Environmental Effects
The
ozone layer acts as a natural filter, absorbing most of the sun's
burning ultraviolet (UV) rays. Stratospheric ozone depletion leads to an
increase in
UV-B that reach the earth's surface, where it can disrupt biological processes and damage a number of materials.
Ozone-depleting Substances
Ozone-depleting
substances generally contain chlorine, fluorine, bromine, carbon, and
hydrogen in varying proportions and are often described by the general
term halocarbons. Chlorofluorocarbons, carbon tetrachloride, and methyl
chloroform are important human-produced ozone-depleting gases that have
been used in many applications. Another important group of
human-produced halocarbons is the halons, which contain carbon, bromine,
fluorine, and (in some cases) chlorine and have been mainly used as
fire extinguishers.
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