Question

World Ozone Day is observed on
1. 2^nd September
2. 16^th September
3. 21^st March
4. None of the above

Answer 1

Correct Answer - Option 2 : 16^th September

Explanation:

• World Ozone Day is observed on 16 September every year, since 1995
• This day reminds the signing of the Montreal Protocol on substances that depletes the Ozone Layer.
• The Montreal Protocol was aimed at protecting the Earth’s ozone layer by eliminating the use of ozone-depleting substances.
• Chlorofluorocarbons (CFCs) are the main substance that depletes the ozone layer.
• The theme of World Ozone Day 2019 is '32 years and Healing'.
• Ozone layer thickness is measured in Dobson units. Ozone is an O3 molecule.
• The ozone layer is present mostly in the Stratosphere and partially in the Troposphere.

Ozone Layer: 

• Ozone (O3) is a molecule formed by three atoms of oxygen. Ozone is a deadly poison.
• Ozone is found in the stratosphere layer of the atmosphere.
• However, at the higher levels of the atmosphere, ozone performs an essential function. It shields the surface of the earth from ultraviolet (UV) radiation from the Sun.
• This radiation is highly damaging to organisms, for example, it is known to cause skin cancer in human beings or can split the DNA.
• It is a pale blue gas with a distinctively pungent smell.
• Ozone is an excellent oxidizing agent as it breaks down into oxygen gas and nascent oxygen. { O3 → O2 + [O] }
• It is an allotrope of oxygen that is much less stable than the diatomic allotrope O2, breaking down in the lower atmosphere to O2 or di-oxygen

Its depletion:

• The amount of ozone in the atmosphere began to drop sharply in the 1980s.
• This decrease has been linked to synthetic chemicals like chlorofluorocarbons (CFCs) which are used as refrigerants and in fire extinguishers.
• The government bans those products which contain CFCs.

• Ozone is thermodynamically unstable and decomposes to molecular oxygen. Thus, a dynamic equilibrium exists between the production and decomposition of ozone molecules