CBSE Class 10 Answered

Hi Nikki,

Ozone layer depletion:

• Depletion in the ozone layer of the atmosphere is called ozone depletion.
• The ozone layer or the ozone shield called the ozonosphere is present in the stratosphere at an altitude of 23–25 km over the equator and at a slightly lower altitude of 11–16 km over the poles.
• The ozone layer functions as a shield against strong UV radiations and protects the Earth from these harmful radiations.

Causes of ozone depletion:

• Methyl bromide
• Nitrogen oxides released from freezers, air conditioners, aerosol products and industrial solvents
• Compounds such as CFCs break down into chlorine atoms in the atmosphere. These chlorine atoms break down O₃ into oxygen (O₂) and nascent oxygen (O).

Effects of Ozone Depletion

• Incidence of skin cancer, cataract and poor immune response in humans.
• Affects crop yield and productivity in plants.
• Marine and terrestrial food chains get disturbed.
• UV-B damages DNA and can result in mutations.

Measures to prevent ozone depletion:

• Limit private vehicle driving
• Avoid using pesticides
• Banning the use of dangerous nitrous oxide