The ozone layer is located on earth’s stratosphere which contain relatively high concentration of ozone ( a
molecule made up of three oxygen atoms).
The ozone layer is crucially important to life because it absorbs biologically harmful ultraviolet (UV) radiation
from the sun.
Ozone Depletion
The thinning of the ozone layer is blamed on the increase in CFCs.
CFCs are used as coolants in refrigerators and air conditioners as aerosol propellants and in foam plastics
production.
CFCs release chlorine atoms when reacting with solar radiation at high altitudes.
The chlorine atoms then cause ozone molecules to break down. Chlorine atoms can remain in the stratosphere
in 100 years, constantly and repeatedly breaking down ozone molecules.
A thinning ozone layer will lead to increased UV radiation reaching the earth’s surface.
This will cause an increase in incidence of cataracts and skin cancers in humans as it increases mutation
rates.
It also suppresses the immune system of animals and humans, and also damages plants and phytoplantonks.
The use of CFCs is being phased out under the terms of the Montreal Protocol, 1987.
The Montreal Protocol is an international agreement that control the production and consumption of
Ozone-Depleting Substances ( ODSs) such as chlorofluorocarbon (CFCs).
ODSs are also gases that contribute to global warming.
CFCs are currently being replaced by HFC molecules which do not break down ozone, and HFCs which has a
low ozone breakdown potential (HCFs will be phased out by 2030).