Ozone

Ozone represented as O3, is found roughly 0.01 ppm in air. Above 0.01 ppm it can be dangerous. It density is 1.5 times that of oxygen and is diamagnetic, which means it defies formation of magnetic field.
We have sometime or the other heard about ozone depletion because of pollution, emissions and need to control global warming. So lets see a bit about ozone layer.
It is found between 10km to 50 km. It has the property of filtering out UV rays, which can be descibed as photons of wavelenth on the shorter side.
Formation: Ozone in stratosphere is formed with UV rays reacting with oxygen.
O2+ Photon ----> 2O
Also, now,
O + O2 ----> O3
This was about formation. Now you will ask how this O3 is depleted by the much hyped chlorofloro carbons, this is how:
O3 + O --------> 2O2
It is destroyed in reaction with atomic oxyegn under presence of some catalysts.
And you guessed right, these catalysts are also fromed due to chlorofloro carbons.
Story ends !