Skin cancer, premature ageing of the skin, cataracts and other eye damage, and suppression of proper functioning of the body’s immune system are all major health problems linked to overexposure Ultraviolet (UV) irradiation. UV irradiation is present in sunlight. 93-99% of this potentially damaging ultraviolet light is absorbed by the ozone layer, a layer present in the earth’s atmosphere that contains a high concentration of ozone.
But since the late 1970s, much of this layer of protective stratospheric ozone has been steadily disappearing. There is a hole the approximate size of the continent of North America in the layer over Antarctica. Less dramatic but significant depletions have been recorded around the globe. Further depletion of the ozone layer, and subsequent exposure to the sun’s UV rays, has the potential to cause immeasurable harm to life on earth.
Chlorofluorocarbons (CFCs) are an important industrial compound. They are the compounds used in some indispensable processes such as refrigerating materials, foam packaging, and aerosol spray cans. There is no natural source for these compounds – their presence in the atmosphere is completely due to human manufacture.
The primary causes of the ozone layer depletion are CFC gases. In the presence of UV radiation, the gas compounds release chlorine atoms. The chlorine atom is capable of destroying a very large number of ozone atoms, and the destruction can go on for up to two years. This phenomenon was first observed in the late 1970s.
The link between ozone layer depletion and skin cancer is very plain. During the last 40 years, the world has seen an alarming increase in the incidence of malignant skin cancer; the rate today is tenfold higher than in the 1950s. It is estimated that a 1% decrease in the zone layer can cause a 2-3% increase in the incidence of skin cancer.