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Depletion of the Ozone Layer and its Impacts
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 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 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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