The ozone layer refers to ozone found in the stratosphere where 90% of the planet's ozone is present. Ozone is made up of three oxygen atoms and the ozone layer absorbs up to 99% of the ultra violet energy from the sun. As the ozone layer is broken down the resulting effect for every 1% of ozone lost is a doubling of the UV light exposure to the lower atmosphere.
Ozone in the lower part of the earths atmosphere (troposphere) acts as a greenhouse gas absorbing some of the heat coming from the earth's surface.
The infamous hole in the ozone layer is over Antarctica and is caused by the presence of CFC’s (chlorofluorocarbons). The thinning of the ozone layer to create the hole happens in the Antarctica each spring.
Below is a NASA image of the hole in the ozone over Antarctica.
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