Introduction to Ozone layer and its depletion

Executive Summary:

• Ozone layer extends approximately from12 km to 45 km in the atmosphere and absorbs most of the ultraviolet radiation reaching the earth from the sun.
• The percentage of Ozone in the atmosphere is only 0.000007 %
• The equilibrium of forming and decomposing ozone in the stratosphere ensured the blocking of UV reaching the surface of earth
• The man made halogenated chemicals used for industrial purposes affected the said equilibrium which resulted the depletion of ozone layer

Ozone (O₃) is a gas composed with three atoms of oxygen. The oxygen molecules (O₂) in the air we breathe are made up of only two atoms of oxygen. Ozone molecules are created in a photochemical reaction in the presence of UV rays, which can be described in a simplified way as,

 3O₂ ⇔ 2O₂ + 2O ⇔ 2O₃

This equilibrium is very fragile and therefore, any intervention could damage the natural processes of formation and breakdown of ozone, which, in turn, would have serious consequences for life on earth.