Question

Which major gas is responsible for ozone depletion?

1. CO₂
2. SO₂
3. CFC
4. NO₂

Answer 1

Correct Answer - Option 3 : CFC

• Chlorofluorocarbons (CFCs) and other halogenated ozone-depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.
• Earth's stratosphere, a thin layer of ozone molecules absorbs ultraviolet sunlight, making conditions at the surface conducive for living beings.
• Chlorine and bromine have similar atomic structures, and they both have the ability to deplete the ozone layer.
•  When a single atom of either element comes in contact with an ozone molecule, it strips the extra oxygen atom to form a slightly more stable molecule -- either a hypochlorite or a hypobromite ion -- and leave molecular oxygen.
• Being far from inert, each hypochlorite and hypobromite ion reacts with another ozone molecule, this time forming two oxygen molecules and leaving the chlorine or bromine radical free to begin the process again. In this way, a single chlorine or bromine atom can convert thousands of ozone molecules into oxygen.