A thin shell of gaseous ozone stretches from roughly 10 to 25 miles above the Earth's surface, and protects the planet from the harmful effects of radiation from the Sun (de Gruijl, 2004). It lies far above the altitude at which commercial aircraft fly and below the altitude at which spacecraft orbit the Earth. The ozone layer is the main barrier between the Earth and the ultraviolet radiation emitted by the Sun. Ozone is a form of oxygen that is selective in screening out the more energetic ultraviolet rays through a process of atomic absorption, while allowing visible light and the warm infrared rays to pass through unchanged.
Ozone depletion results in more ultraviolet radiation reaching the Earth's surface, which poses a threat to humans (Health, 2006). Overexposure to ultraviolet (UV) radiation causes: skin cancer (melanoma and nonmelanoma); premature aging of the skin; cataracts and other eye damage; and suppresses the immune system. The incidence of skin cancer has risen considerably in recent years since the appearance of a hole in the ozone layer over the Antarctic in the 1980s. The incidence of melanoma, a rapidly growing form of cancer caused by UV radiation, and the most serious form of skin cancer, has more than doubled in the last 20 years. Nonmelanoma skin cancers have also increased with basal cell carcinomas being the most common type. These types of cancers appear as small, slow growing lumps or nodules which rarely spread. Squamous cell carcinomas appear as red, scaly patches and may spread to other parts of the body. Cataracts and immune suppression add to the dangers to humans from depletion of the ozone layer.
de Gruijl, F.R. (2004). Impacts of a projected depletion of the ozone layer. Retrieved Feb. 27, 2006 from
http://www.gcrio.org/CONSEQUENCES/summer95/impacts.html
Health effects of overexposure tot he sun. (2006). Retrieved Feb. 27, 2006 from
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