Question

Why is trioxygen (ozone), O3, a greenhouse gas whereas dioxygen, O2, is not?

Answer 1

Ozone is unstable structure because it has 3 oxygen atoms and overall molecule is polar because of unequal distribution of charge. In ozone the central atom has +1 charge , while the other bonded oxygen has -1 charge . It's this separation of charges that creates the dipole moment. Hence it is readily combines with other atoms to convert stable product. Where as O2 is stable and non reactive in mild condition. As well O2 has permanent magnetic moment because of aligned spin of the unpaired electrons in O2 molecules

Ozone molecules present in the stratosphere which absorb shortwave energy from sun, and it prevents this radiation from passing to the earth's surface. Ozone effectively absorbs the most energetic ultraviolet light, known as UV-C and UV-B, which causes biological damage.