Question

Which of the following chemical cause the thinning of layer P?

• A. Carbon monoxide
• B. Sulphur dioxide
• C. Chlorofluorocarbons
• D. Both A and C

Answer 1

Answer: (C)

Chlorofluorocarbons

Chlorofluorocarbon (CFC) is composed of carbon, fluorine, and chlorine. CFCs are also called freons. CFCs, once released into the atmosphere, accumulate in the stratosphere, where they react with ozone ($O_3$) and contribute to the depletion of the ozone layer by breaking the O${}_3$ into O${}_2$ and free oxygen. Stratospheric ozone shields life on earth from the harmful effects of the sun's ultraviolet radiation; even a relatively small decrease in the stratospheric ozone concentration can result in an increased incidence of skin cancer in humans and genetic damage in many organisms.