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The Ozone Layer is a naturally occurring protective layer in the
stratosphere, about fifteen miles above the Earth's surface, that absorbs some of
the sun's ultraviolet rays, thereby reducing the amount of potentially
harmful radiation that reaches the Earth's surface. The destruction of
the ozone layer is caused by the human-caused, increased presence of certain chlorine- and/or
bromine-containing compounds (chlorofluorocarbons or halons, "CFCs"), which
chemically change when they reach the stratosphere and then break up ozone
molecules, thinning the ozone layer, and increasing the amount of ultraviolet radiation that
reaches the Earth's surface. This stratospheric Ozone is essential for life on Earth.
Ozone in the atmosphere near the Earth's surface ("Ground Level Ozone") is caused primarily by human activity, and forms with hydrocarbons a photochemically derived compound called "smog". The hydrocarbons are the waste products of combustion from vehicles and industries.
Near the Earth's surface Ozone is a pollutant, especially in urban areas, and causes respiratory damage in animals, and cellular damage in plants, among other impacts. The basic ingredients are high concentrations of hydrocarbons in the air, low windspeed, warm temperature, and strong sunlight. This resulting ground level Ozone is hazardous to life on Earth. |
