CFCs - Chlorofluorocarbons
Chlorofluorocarbons (CFCs), along with other chlorine and bromine containing
compounds, are thought to be one of the major group of chemicals that
are causing the depletion of ozone layer.
The invention of chlorofluorocarbons (CFCs) in the late 1920s and early
1930s stemmed from the call for safer alternatives to the sulphur dioxide
and ammonia refrigerants used at the time. They are non-toxic, non-flammable,
and non-reactive with other chemical compounds. This made them to be
considered as very safe and ideal for many applications -- such as coolants
for commercial and home refrigeration units, aerosol propellants, electronic
cleaning solvents, and blowing agents. They were very popular and widely
used.
In 1973 chlorine was discovered to be a catalytic agent in ozone destructionand
it was realizes that CFCs were potentially damaging to the ozone layer.
However, conclusive evidence of stratospheric ozone loss was not discovered
until 1984. the announcement of polar ozone depletion over Antarctica
in March 1985 prompted scientific initiatives to discover the Ozone
Depletion Processes, along with calls to freeze or diminish production
of chlorinated fluorocarbons.
Nowadays fridges and aerosols are marked 'Ozone- friendly' or 'CFC-free'
to show that they are no longer used but the CFCs that are already in
the upper atmosphere are still depleting ozone and will for some time
to come.