Formation and Depletion of Ozone

 The ozone layer is located in the stratosphere, located about 12 km to 50 km above Earth's surface. This zone is known to be dynamically in equilibrium with oxygen, and it's continually changing that is: being formed and decomposed. But how does it work? The oxygen bond is broken by UV radiation emitted from the sun.The new oxygen atom is called free radical for it has 1 unpaired electron 

 
UV(high energy)
O=O(g)  --------------->  2 O ● (g)
O ●(g)  +  O2(g) --------> O3(g)

 UV(low  energy)
O3(g) ---------------> O2(g)  +  O●(g)
O3(g)  +  O●(g)  -----------> 2O2(g)