This continuous cycle keeps ozone at it's correct level. .
In the 1970's, scientists first discovered that chlorofluorocarbons (CFC's) potentially could destroy the ozone layer, and since CFC's had been in use as refrigerants, coolants, and propellants for aerosol cans since the 1930's, there was could have a lot of damage already done. However, only in the 1070's, the dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed. .
Over Antarctica, stratospheric ozone has been depleted over the last 15 years at certain times of the year. This is mainly due to the release of manmade chemicals containing chlorine such as CFC's, but also compounds containing bromine, other related halogens and also nitrogen oxides (NOx). .
The Ozone Layer.
Chemical processes.
Ozone is a naturally occurring trace gas, chemical formula O3. In the stratosphere, it serves to absorb many harmful solar UV rays.
The atmosphere is about 1000 km (600 miles) thick. Atmospheric layers, as measured in distance from the Earth's surface, are: .
Troposphere (0 to 10 km; 0 to 6 miles).
Stratosphere (10 to 50 km; 6 to 30 miles).
Mesosphere (50 to 80 km; 30 to 50 miles).
Thermosphere (80 to 600 km; 50 to 400 miles).
Exosphere (600 to 1000 km; 400 to 600 miles).
The public's attention is caught mostly by the stratospheric ozone layer and its ability to absorb ultraviolet (UV) light. The ozone layer shields the Earth's surface from the full fury of solar UV radiation. In the process, ozone is created and destroyed, breaking up into diatomic oxygen and an oxygen atom:.
O3 + UVO2 + O (equation 1).
Diatomic oxygen can also be split by UV light to yield two oxygen atoms:.
O2 + UVO + O (equation 2).
Ozone is resynthesized by the combination of diatomic oxygen and one of the oxygen atoms liberated in equation 1 or equation 2:.
O2 + OO3 (equation 3).
Ozone is depleted when the natural balance is tampered with by humans. UV rays are normally used up in the natural process of producing and destroying ozone.