Q.What do you mean by ozone hole? What are its consequences?

The ozone hole is the term used for the region of the stratosphere, especially over Antarctica, where the concentration of ozone drops dramatically (well below normal) during a particular season (spring, around September–November in the Southern Hemisphere). It was first detected by scientists in the 1980s. Although called a 'hole', it is really a large area of severely thinned ozone rather than a complete absence of ozone.

Cause: The depletion is driven by chlorine and bromine free radicals released mainly from chlorofluorocarbons (CFCs) once they reach the stratosphere, through the catalytic ozone-destruction cycle (Cl + O3 → ClO + O2; ClO + O → Cl + O2). Unique atmospheric and temperature conditions over Antarctica (polar stratospheric clouds, polar vortex) intensify this effect there.

Consequences of ozone depletion (the ozone hole):

• The ozone layer normally absorbs most of the sun's harmful ultraviolet-B (UV-B) radiation. When it thins, more UV-B reaches the earth's surface.
• Increased UV-B exposure raises the incidence of skin cancer and premature skin ageing in humans.
• It can cause cataracts and other damage to the eyes. …

Define the ozone hole as severe seasonal ozone thinning over Antarctica caused by CFCs, then list its consequences under human health, …

• Describing it as a literal physical 'hole' with zero ozone, rather than a region of severe thinning.
• Forgetting to connect the consequence back to the underlying cause: less ozone means less UV-B absorption, hence more UV-B reaching the surfa …