What is the ozone layer?
High in the atmosphere a layer of ozone protects life on earth from the damaging ultra violet rays of the sun. Ozone, which is composed of three oxygen atoms bound together, is a naturally occurring substance and is present at very low concentrations throughout the atmosphere. The concentration is highest in the stratosphere, which is the atmospheric layer between approximately 10-15 to 50km above the Earth's surface.
Why is the ozone layer important?
The ozone layer filters out much of the potentially harmful ultraviolet radiation from the sun that enters the atmosphere. (Radiation at wavelengths between 240 and 320 nanometers is absorbed by ozone.) Any depletion of the ozone layer results in an increase in UV radiation reaching the earth's surface, which can have a detrimental impact on our environment and health.
Most living species have some natural tolerance to UV radiation, but it is now well known that even moderate exposure carries a risk of harmful effects. In humans, enhanced long-term exposure is likely to increase levels of skin damage including sunburn and skin cancers and of eye abnormalities such as snow blindness and cataracts. UV radiation can also suppress the immune system with potentially serious consequences for the spread of infectious diseases.
Animals, plants and marine life may experience similar effects, and there are consequences for biodiversity and food supply. For example, harmful effects on aquatic life tend to occur just below the surface of the water where eggs and larvae of many species are found, and where plants forming the foundation of the food chain are most abundant. Many crops, such as wheat, barley, rice and soybean, are vulnerable and crop yield and quality can both be affected.