The ozone layer is important because it filters harmful ultraviolet radiation as it travels from the sun to the surface of the Earth. These ultraviolet rays can harm both plant and animal life. After observation of a depletion of the ozone layer from the addition of chlorofluorocarbons and other man-made chemicals, the Montreal Protocol was enacted on Jan. 1, 1989 as an attempt to eradicate these chemicals from the atmosphere.
Ozone is found in the stratosphere, a layer of air that encircles the globe approximately 6 to 30 miles above its surface. When ultraviolet radiation strikes this layer of air, it interacts with the ozone and is chemically decomposed. Even with the ozone filter, some ultraviolet radiation reaches the Earth. This radiation is responsible for skin cancer and stunting of plant growth.
In the 1980s, inquiry into the cause of the depletion of the ozone layer led to investigation of chlorofluorocarbons, which are chemicals used in refrigerants, insulating foams and solvents. Once chlorofluorocarbons are released into the atmosphere, winds buffet them upward where they interact with ozone, destroying the ozone molecules. In addition to chlorofluorocarbons, pesticides containing methyl bromide, halons used in fire extinguishers and methyl chloroform found in industry solvents are known to destroy ozone.