09 October 2008
Ozone hole getting bigger and bigger
Ozone in the earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O2), splitting them into individual oxygen atoms (atomic oxygen); surface. Ozone concentrations are greatest between about 20 and 40 km.
Ozone layer helps us in many aspects. It filters sunlight, shielding life on Earth from harmful ultraviolet rays which can increase the risk of skin cancer and cataracts and harm marine life.
It has been identified that this year the area of the thinned ozone layer over the South Pole reached about 27 million square km, compared to 25 million square km in 2007 and a record ozone hole extension of 29 million square kilometres in 2006, which is about the size of the North American continent.
The depletion of ozone is caused by extreme cold temperatures at high altitude and the presence of ozone-destructing gases in the atmosphere such as chlorine and bromine, originating from man-made products like chlorofluorocarbons (CFCs), which were phased out under the 1987 Montreal Protocol but continue to linger in the atmosphere.