#Biology #ozonedepletion

• Ozone is a gas found in a layer high up in atmosphere.

• The ozone layer protects us from ultraviolet radiation.

• Cfcs have damaged the ozone layer over the Antarctic.

• Cfcs are now banned and the ozone layer is recover.

The 'hole' in the ozone layer

In 1985 , scientists discovered that there was less ozone than there should be over the Antarctic, especially in the Antarctic spring. They called this the ozone hole. The ozone hole isn't really a hole . It is just an area where there is less ozone than normal.

What is cfc (chloro-fluorocarbon) ?

CFC are man made . They were invented in the 1920s . They were used in air conditioners, refrigerators aerosol cans .No -one knew that they were harmful.

Cfcs rise up high into the atmosphere. They react with ozone and break it down . This happens especially when it is cold , and when sunlight shines onto the cfcs and ozone.

3.5 pg no 46 and 47