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The ozone layer is found in the upper stratosphere and its primary function is to filter ultraviolet short-wave radiation that comes from the sun. Ozone gas absorbs UV radiation. The 'hole' in the ozone layer was first noted in the 1980's, and is of concern as increased levels of UV radiation can leads to increased levels of skin cancer and eye cataracts.
At first the ozone hole was only found over Antarctica, but it has been becoming larger at a rapid rate, and now affects parts of Chile and Australia. Although some natural repair occurs each year, it is not sufficient to limit the damage. The problem is worsened as CFC's are a primary cause of the damage and they remain in the stratosphere for up to 100 years.
|CFC's||The increase in the size of the hole in the ozone layer is directly linked to increased production of CFC's since the 1950's in aerosols, plastic foam, fast food packaging and fridges. Chlorine is produced by CFC'S and reacts strongly with ozone in the stratosphere, breaking down the ozone layer.|
|Natural causes||Volcanic eruptions, as they release carbon monoxide and decrease nitrogen oxides in the atmosphere. Methane from rotting vegetation.|
|Health||Main concern is the increase in levels of UV radiation and the link to skin cancer. It is also connected to eye damage, where the cornea, retina and lens may be damaged. In severe cases, cataracts form.|
|Vegetation||Inhibits photosynthesis in plants and increase likelihood of disease. Some evidence is contradictory.|
|Global warming||Large amounts of UV radiation can kill plankton found in oceans, which absorbs carbon dioxide, thus increasing the rate of global warming.|
|Other effects||Places stress on marine ecosystems reduces strength of wood and plastic products.|
|Education||Pioneered in Australia, with the Sunsmart Campaign, advising people to cover up when out in the sunshine to reduce the damage caused by UV radiation.|
|Government legislation||Australia in 1989 'Ozone Protection Act' banning production of import and manufacture of all CFC's. Restriction of aerosol use.|
|Removal of CFC's||Government legislation combines with development of alternatives to CFC's. Labelling of products as 'ozone friendly' to provide consumer choice. Pump action sprays instead of aerosols.|
|International agreements||Various, beginning with the Montreal Protocol in 1987, where measures have been taken to reduce CFC production. 1992 EU countries agree to halt CFC production by 1995.|