Question

In atmosphere , Ozone hole refers to

• A. A hole in ozone layer
• B. Decrease in ozone layer thickness in troposphere
• C. Decrease in thickness of ozone layer in stratosphere
• D. Increase in the thickness of ozone layer in troposphere

Answer 1

The correct option is C Decrease in thickness of ozone layer in stratosphere

The region of stratosphere, at an altitude of 16-50km over equator and at a slightly lower altitude elsewhere having a thick sheet of ozone is known as ozonosphere. Decline in the thickness of ozone layer over a restricted area is called ozone hole. It was first discovered over Antarctica in 1985 by Dr. Joe C. Farman and his colleagues in the British Antarctica surveys. Chlorofluorocarbons are mainly responsible for ozone depletion in the stratosphere. CFC's are used as coolants in refrigerators and air conditioners, as propellants, cleaning solvents. Once released into the atmosphere, CFC'S reach the stratosphere and produce active chlorine in the presence of UV radiations. These radicals through chain reaction destroy ozone by converting it into oxygen.

Thus, the correct answer is option C.