This atmosphere extends many miles out from the earth's surface. However, this layer is not a uniform layer, from top to bottom. As one moves out from the planet's surface the atmosphere becomes progressively dense. This atmosphere can be divided into four major regions.

The first region is the troposphere which extends about 6.5 miles above the planet's surface. The troposphere contains the oxygen that we breathe and is where a majority of our weather takes place. Beyond the troposphere is the second region of the atmosphere, the stratosphere. The stratosphere extends from roughly 6.5-30 miles from the earth's' surface. The air on this region is much less dense than in the troposphere, and it's a lot drier. The s

The ozone is made in the stratosphere. It is continuously being formed, broken down, and reformed, over and over again. Furthermore, the three key elements of the cycle are: oxygen, ozone, and the energy from the sun. The ultimate source of energy for our planet is the sun. This energy travels through space in the form of electromagnetic Radiation. Furthermore, this electromagnetic radiation is often referred to as waves and their length, therefore, wavelengths. The sun has a wide range of wavelengths. This range is known as the Electromagnetic Spectrum. In this spectrum there is Gamma, Ultraviolet, Visible, Infrared, and Radio waves.

In conclusion, despite the increasing list of negative affects of UV radiation, we continue to release ozone depleting chemicals into the atmosphere. Despite the availability of safer alternatives, we continue to promote technologies that are only slightly safer than the ones they replaced. Despite all of the current information on the destructive affects of Cfcs, we still continue to use them on a mass scale. Scientific research has only begun to discover the impacts of UV radiation; however, what we do know should be enough for action. We cannot afford to sit around and wait for the damage to reach a point that makes us react, by then it will be too late. The time to act is now because even with an immediate and complete end to production and release of ozone-depleting substances to the environment, we are still left with many decades of decreasing ozone and increased UV exposure.

After Cfcs reach the stratosphere and come into contact [photolyze] with UV radiation, the chlorine atoms are released. Furthermore, due to their high reactivity, the chlorine does not remain single for very long, they rapidly join nearby molecules. Since these reactions are occurring in the ozone layer, many of these nearby molecules are ozone molecules. When a chlorine atom and an ozone molecule come together, the chlorine atom binds to one of the oxygen atoms on the ozone molecule. “As a result of the reaction, the ozone molecule is destroyed and a molecule of oxygen and chlorine monoxide (CIO) are left over” (Rowland 1989 p.71).

Past the stratosphere is the mesosphere which extends to 50 miles above the planet. The last region is the thermosphere. The thermosphere's outermost edge is roughly 600 miles above the surface of the earth. Beyond it, the airless vacuum of space begins.

The types of UV rays absorbed by the ozone layer are the same ones that are most harmful to humans; skin cancer and cataracts. Furthermore, depletion of the ozone layer results in increased UV radiation exposure. One affect of UV on humans is skin cancer. “Most skin cancers fall into three classes: basal cell carcinomas, squamous cell carcinomas, and melanomas. In the US there were 500,000 cases of the first, 100,.000 cases of the second, and 27,000 of the third type, in 1990”(Wayne p. 47). Furthermore, cases of melanoma have been estimated to be increasing at an average of 10% from 1979 to 1993 and even larger increases are believed to be occurring in the southern hemisphere. Also, studies suggest that a 1% decrease in stratospheric ozone will result in a 2%

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