Destroying the Ozone Shield

Ozone, a form of oxygen consisting of three atoms of oxygen instead of two, is considered an air pollutant when found at ground levels and is a major component of smog. It is formed by the reaction of various air pollutants in the presence of sunlight. Ozone is also used commercially as a bleaching agent and to purify municipal water supplies. Since ozone is toxic, the gas is harmful to health when generated near the earth's surface. Because of its high rate of breakdown, such ozone never reaches the upper atmosphere.

But the ozone that shields the earth from the sun's radiation is found in the stratosphere, a layer of the upper atmosphere found 9–30 mi (15–50 km) above ground. This ozone layer is maintained as follows: the action of ultraviolet light breaks O₂ molecules into atoms of elemental oxygen (O). The...