(a) What is ozone? How is it formed?(b) How does ozone layer protect us from harmful effects in the environment?(c) What is UNEP? What step has been taken by UNEP in 1987 to prevent too much damage to the ozone layer?

(a) Ozone is made up of three atoms of oxygen combined together. It is formed high up in the atmosphere by the action of ultraviolet (UV) radiation on oxygen gas. The UV radiation from the sun splits the oxygen gas into free oxygen atoms.

$O_2 (Oxygen\ molecule)  → O (UV\ radiation\ from\ the\ sun) + O (Oxygen\ atom) + O (Oxygen\ atom)$

                                 

An oxygen atom reacts with an oxygen molecule to form an ozone molecule.

$O_2 (Oxygen\ molecule ) + O(Oxygen\ atom) →  O_3 ( Ozone\  molecule)$

(b) The ozone layer protects us from the harmful effects of the UV radiation from the sun by absorbing it and preventing it from reaching the earth's surface.

(c) The UNEP is United Nations Environment Programme. In 1987, in an attempt to protect the ozone layer, the UNEP forged an agreement among its member countries to freeze the production of chlorofluorocarbons at 1986 levels.