The Ozone Case - Ultraviolet Radiation

Ultraviolet radiation has a higher frequency and more energy than the energy of visible light. This radiation comes from the sun. It is important for the creation of the ozone.

It spilts oxygen molecules to form oxygen free radicals which are necessary for the reactipn during which ozone is formed. The radiation of the sun desroys ozone by decomposing the ozone molecules into oxygen molecules and oxygen free radicals. During this process oxygen is absorbed.

Ozone formation is a very slow process considering that there is not much solar radiation with wavelengths less than 240nm. A third neutral party like oxygen or nitrogen usually absorb the excess energy and convert the energy into kinetic energy.

Ozone construction and destruction is therefore a process that repeats itself. The ozone absorbs ultraviolet rays, the ozone opposes the radition stoping it from reaching earth. For example, the ozone can: cause skin cancer in humans and animals; weakens the human immune system; prevents plants growing; reduce the growth of plankton in the oceans.

Chlorofluorocarbons (CFC's), and chemicals like it, do not bond easily with other chemicals. This makes them nontoxic and ideal for use in manufacturing processes. Because CFCs are so unreactive, they do not decompose in the lower atmosphere as most chemicals do. Instead, they travel up to the stratosphere where the ozone layer exists. There they are broken down by ultraviolet radiation and release chlorine atoms. These chlorine atoms react chemically with ozone molecules and catalyze their breakdown into oxygen molecules.

After CFC's are emitted, it takes ten years for them to reach the stratosphere. Once there, they can continue to destroy ozone molecules for 75 to 100 years, depending on their type. Most continue for about 100 years with each CFC molecule destroying approximately 100,000 ozone molecules. Compounding this is a process called "banking". Since not all CFCs are emitted at the time of manufacture, some CFCs may take 15 years or more to escape from products such as refrigerators and foam insulation. As a result, CFCs produced today will affect the ozone layer for a century or more."

The United States and Britain are currently developing substitutes for CFCS. Dupont, one of the world's leading producers of CFCs, announced that it now has two possible substitutes for CFCs used as cleaning agents by electronics companies. These account for about 20% of world consumption. Dupont has also stated that it now has good substitute prospects for all major CFC markets.