Ozone Essay, Research Paper

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

fluorocarbon-11 and fluorocarbon-12 are being implemented in a number of

nations. Yet scientist are still concerned for what the future holds.

Scientist have estimated that the average rate of ozone depletion is 0.5%

per year. For this reason, scientists are pushing for finding some option to

fix the disaster.

Hydrofluorocarbons and hydrochlorofluorocarbons have been proposed as CFC

replacements. The atmospheric combinations expected to produce

trifluoroacetate (TFA), which is removed mainly by the rain. Yet there still

are problems which scientist are trying to sort out. The global average TFA

concentration is very low, yet there is some concerns in situations of high

evaporation, and the affects of TFA. TFA in high concentration could

inhibit the plant growth, a risk that could turn disastrous.

Another harmful ozone destroyer is Mythl bromide which is used by farmers

for pests control, which is found in leaded gasoline, and Marine plants

discharge it into the air. Mythl bromide reacts the same way as

chloroflurocarbons, with the bromide molecule destroying the ozone. Why

Mythl bromide is not as much of a problem as CFCs is because bromide does

not survive as long in the atmosphere. By 1991, CFC’s had been firmly

established chlorine as the principle cause of the destruction of the ozone

molecule, but scientist are still unsure about the degree of danger that

myth bromide and other compounds pose to the ozone layer.

To determine the depletion of the ozone layer, the National Aeronautic and

Space Administration (NASA) has been studying the stratosphere and to

measure the concentration of ozone, aerosol particles, nitrogen oxides,

hydrogenoxied, and CFCs. Scientist studying the effects of the depletion

of ozone agreed that there was a growing erosion in the ozone layer.

Scientist have also agreed that the ozone layer has dropped to as much as

10%. There is a scary parallel in the rise in the amount of ultraviolet

rays and the hole in the ozone. This threatens all living things. Scientist

have predicted a 5 to 20 percent increase in ultraviolet radiation in the

next 40 years. Some scientists have also predicted that for every 1%

decrease in the ozone layer, there will be a 2% increase in the in incidence

of skin cancer. The increase of ultraviolet radiation (UVR) is one of the

main risk factors for skin cancer. High exposure to ultraviolet radiation

can weaken the immune system.

In plants, the cells are damaged by the rise in ultraviolet radiation. With

the continuing rise in ultra-violet B radiation (different frequency 280-320

nm) plants have become the next victims. In plants, there are several

targets for UV-B rays. UV-B rays slow down the photosynthesis,

productivity, and growth in plants. Such affects could mean 20% to 25%

decrease in crop yields. UV-B rays directly damages the plants DNA in the

chloroplast. From absorption of the high energy photons, the plant becomes

damaged . For the increasing levels of UV-B rays and UV-A rays, farmers

worry about the highly possible reduction in yields.

Scientists have done a lot to research a problem that has been recently

been discovered. In the understanding of how the ozone layer works, and it^?s

importance, finding a way to stop the depletion of the ozone layer has

become necessary. The Ozone layer is essential for their to be life on

earth. All living things can not live in an environment of high radiation.

For this science and humans are looking for ways to fix the problem.

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