Ozone

Ozone

Ozone is an important molecule in maintaining the homeostasis in the

environment. Ozone, the molecule O3, makes a layer in the stratosphere,

situated 10 to 15 kilometers from the earth's surface. The dioxide

molecule, O2 and Oxygen atom O, collide with each other result in the

formation of Ozone, O3. In this reaction, the molecule O3 contains an excess

of energy. Once the molecule is formed, it is not stable enough to last

long. The energy-rich O3 molecules discards the excess energy by colliding

with another atom or molecule and transferring the energy in the form of

heat. In the results of the decomposition of ozone into O2 and O in the

ozone layer, solar radiation is absorbed. This process of the chemical bond

breaking causing the absorption of a photon by a molecule is called

photodissociation. Radiation with sufficient intensity, is capable of

separating the O3 molecule, resulting in photodissociation. The cyclic

process formation and decomposition of ozone provides a shield against

ultraviolet radiation that enter the earth's atmosphere. If it were not for

the chemical reaction of radiation and ozone in the stratosphere, these

high-energy photons would penetrate the earth's surface. The ozone layer

absorbers about 99% of the harmful radiation which makes it possible for

animals and plants to live on the planet.

In 1974, F. Sherwood Rowland and Mario Molina of the University of

California proposed that chlorine from chlorofluorocarbons (CFCs) could

deplete the ozone layer. Beginning in 1957 to 1985, the British Antarctic

Survey had measured the average ozone concentration over Halley Bay in

Antarctica. Up until 1974, the ozone concentration remained stable. Yet

after 1974, the team observed a decline of the ozone layer to levels less

than 10%. From this study the awareness over the danger of the "hole" and

ultraviolet radiation and the destruction being done to the earth.

Scientists believe the expanding ozone hole, which is centered over

Antarctica was caused by Chloroflurocarbons. CFCs are released into the

environment through such sources as spray cans , air conditioners,

factories, refrigerants and cleaning products. CFCs are dangerous to the

atmosphere because after they are released into the environment, the

sunlight breaks down the compound. The chlorine molecules react with the

ozone molecules by permanently breaking down the molecule, thus diminishing

the ozone layer. This rise poses a major threat environment. In 1985, in

Vienna and in 1987 in Montreal, a Protocol was signed proposing the gradual

termination of use of CFCs over the decades. A dramatic reduction in the

use of CFCs was agreed on. Regulations to limit the production of