Ozone depletion is the process where ozone holes are created in the ozone layer. The main reason for ozone depletion are the chlorofluorocarbons (CFCs) found in everyday products such as refrigerator coolant, fire extinguishers, and in aerosol cans. These were released into the atmosphere during the second half of the twentieth century and their effects are still being felt.
Chlorine is released from the CFCs which
destroys the ozone. The major cause of ozone deletion is the pollution of the
environment. This is mainly done when halons are released into the atmosphere.
Causes of Ozone Depletion
Ozone is a triatomic form of oxygen (O3),
found in the Earth's atmosphere. A combination of low temperatures, elevated
chlorine and bromine concentrations in the upper stratosphere are responsible
for the destruction of ozone. The production and emission of
chlorofluorocarbons (CFCs), is the leading cause of ozone layer depletion.
CFC's accounts for almost 80% of the total depletion of ozone.
Other ozone-depleting substances (ODS),
include hydrochlorofluorocarbons (HCFCs), and volatile organic compounds
(VOCs). These are often found in vehicle emissions, byproducts of industrial
processes, refrigerants, and aerosols. ODS are relatively stable in the lower
atmosphere of the Earth, but in the stratosphere, they are exposed to
ultraviolet radiation and thus, they break down to release a free chlorine
atom.
This free chlorine atom reacts with an ozone molecule (O3), and forms chlorine monoxide (ClO), and a molecule of oxygen. Now, ClO reacts with an ozone molecule to form a chlorine atom, and two molecules of oxygen. The free chlorine molecule again reacts with ozone to form chlorine monoxide. The process continues, and this results in the depletion of the ozone layer.