The ozone layer diminishes more each year.
polar ozone depletion (commonly called the ozone hole) gets .
larger, additional ultraviolet rays are allowed to pass through. .
These rays cause cancer, cataracts, and lowered immunity to .
diseases.1 What causes the depletion of the ozone layer?.
In 1970, Crutzen first showed that nitrogen oxides produced .
by decaying nitrous oxide from soil-borne microbes react .
catalytically with ozone hastening its depletion. His findings .
started research on "global biogeochemical cycles" as well as the .
effects of supersonic transport aircraft that release nitrogen .
oxide into the stratosphere.2 .
In 1974, Molina and Rowland found that human-made .
chlorofluorocarbons used for making foam, cleaning fluids, .
refrigerants, and repellents transform into ozone-depleting .
agents.3.
.
Chlorofluorocarbons stay in the atmosphere for several .
decades due to their long tropospheric lifetimes. These compounds .
are carried into the stratosphere where they undergo hundreds of .
catalytic cycles with ozone.4 They are broken down into chlorine .
atoms by ultraviolet radiation.5 Chlorine acts as the catalyst .
for breaking down atomic oxygen and molecular ozone into two .
molecules of molecular oxygen. The basic set of reactions that .
involve this process are:.
Cl + O3 -->ClO + O2 and.
ClO + O -->Cl + O2.
The net result:.
O3 + O -->2O2.
Chlorine is initially removed in the first equation by the .
reaction with ozone to form chlorine monoxide. Then it is .
regenerated through the reaction with monatomic oxygen in the .
second equation. The net result of the two reactions is the .
depletion of ozone and atomic oxygen.6.
Chlorofluorocarbons (CFCs), halons, and methyl bromide are a .
few of the ozone depletion substances (ODS) that break down ozone .
under intense ultraviolet light. The bromine and fluorine in .
these chemicals act as catalysts, reforming ozone (O3) molecules .
