Question

The major cause for depletion of ozone layer in stratosphere is due to the

• A. increase in the level of greenhouse gases
• B. increased usage of CFCs
• C. decreased use of CFCs
• D. increase in sulphur dioxide and carbon monoxide

Answer 1

The correct option is B

increased usage of CFCs

The ozone depletion process begins when CFCs and other ozone-depleting substances (ODS) are emitted into the atmosphere. Winds efficiently mix the troposphere and evenly distribute the gases. CFCs are extremely stable, and they do not dissolve in rain. After a period of several years, CFC molecules reach the stratosphere, about 10 kilometers above the Earth's surface.

Strong UV light breaks apart the ozone depleting molecules. CFCs release chlorine atoms.It is these atoms that actually destroy ozone. It is estimated that one chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere .