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... is so lethal that without the stratosphere ozone layer, the existence of life on earth would be nearly impossible. All living organisms would suffer from too much mutation in the organism that all of its major organs would just stop working; and the organism would die. Until the 1970 s and 1980 s, most people, including scientists, took the ozone layer more or less for granted. They assumed it was one of the earths natural features and that it would always remain the same, This attitude changed in 1984 when scientist found a huge hole in the ozone layer over Antarctica, the continent covering the planets south pole.
Since then, researchers have discovered that the stratosphere ozone shield is growing thinner and weaker. As this happens, more ultraviolet light reaches the earths surface. This is why scientists and government officials around the world are increasingly concerned about the possible health effects of upper-level ozone depletion. At the beach, when people lie under a warm summer sun, many leave with attractive golden tans while others, especially those with fair skin, get painful red sunburns. Ultraviolet rays striking and damaging the cells on the skins surface cause both the tans and sunburns.
Scientists and doctors have known for a long time that repeated exposure to ultraviolet radiation causes skin cancer. In general, light-skinned people have the highest risk, while dark-skinned people of a much lower risk. This is because darker skin contains more of the pigment melanin, which blocks out most of the ultraviolet light. About ninety percent of all skin cancers occur on the head and the neck, mainly because these are the areas of the body that are most often left uncovered and exposed to the sun.
As might be expected, skin cancer rates are highest for people who frequently work or play outside in the sun. About 400, 000 to 600, 000 cases of skin cancer occur in the United States each year. (Heppenheimer, 1990) Many of these cases are caused by too much exposure to ultraviolet rays from the sun. Most skin cancer, if caught early, is curable. But about six thousand people still die each year from the disease. As the intensity of ultraviolet radiation increases, cancer rates and deaths may also increase. Many scientists expect that as upper-level ozone decreases, the intensity of ultraviolet radiation at the earths surface will increase.
According to the EPA, Environmental Protection Agency, for every 1 percent decrease in the ozone layer, ultraviolet rays reaching the earths surface will increase two percent. This, in turn, could cause an 8 percent rise in skin cancer in the United States, every year. (Heppenheimer, 1990) Ultraviolet light is also a major cause of eye cataracts. These are patches of opaque, or light blocking, tissue that form in the eyes and can lead to partial or complete blindness. Laboratory experiments have shown that ultraviolet rays are 250 times more likely than regular light to cause cataracts. According to the EPA, if the present rate of ozone depletion continues for the next forty years, the increased ultraviolet radiation could cause as many as ten million extra cases of cataracts in the United States alone. (Heppenheimer, 1990) Animals and people are not the only creatures harmed by ultraviolet rays. Many microorganisms that produce nutrients in the soil die from overexposure to these rays.
The microorganisms are extremely sensitive to change in the intensity of the rays. So continued upper-level ozone depletion could potentially decrease soul fertility, especially in tropical biomes where ultraviolet radiation is naturally more intense. Plants, too, can suffer from increased doses of ultraviolet rays. According to researchers Robert C.
Worrest of the EPA, scientists have tested about two hundred species of land plants, but mostly food crops, for sensitivity to ultraviolet light. He found that it reduces the crop yield, the stem and leaves dont grow as much and the total dry weight is lessened. Worrest and his colleagues stress that scientific knowledge in this area is still limits and that thousands of other plant species have not yet been tested. They call for more worldwide studies.
More information, they say, will help prevent potentially serious crop losses that might ozone depletion continues. All these potentially harmful effects of ultraviolet radiation are a cause for concern to scientists and government leaders around the world. Researchers work to discover the reasons why this ozone depletion occurs. They also search for ways to slow and eventually halt the destruction of upper-level ozone. This research is relatively new.
Until a few years ago, no one knew about the Antarctic ozone hole or even that a decrease of upper-level ozone was possible. The discovery of ozone depletion came in the early 1970 s. Before that, scientists paid little attention to the ozone layer. This was mainly because they did not yet thoroughly understand the chemistry of the upper atmosphere. In 1970, two atmospheric scientists independently made the same suggestion. Paul Crutzen, then researcher at the University of Stockholm in Sweden, and Harold Johnson, a researcher at the University of California at Berkeley, each suggested that exhaust from high flying airplanes would introduce large amounts of pollutants into the atmosphere.
These pollutants, the scientists said, might seriously damage the ozone layer. Crutzen and Johnsons idea generated a great deal of publicity because, at the time, several countries were considering building fleets of supersonic aircraft that would fly high in the atmosphere. The United States, France, and Great Britain all proposed launching these passenger carrying craft. The United States eventually cancelled its plans. This was partly due to fear of damaging the upper ozone level. Meanwhile, both France and Great Britain built their supersonic fleets.
Now, only a few of the aircraft are in use, and they have not noticeably affected the upper ozone level. The next step in the search for the ozone-destroying culprit came in 1974. Richard Stolarski and Ralph Cicerone, both of the University of Michigan, did a study for the National Aeronautics and Space Administration (NASA). They wanted to see if exhaust from the space shuttles would affect the ozone layer. They found that one element in the exhaust, chlorine, did affect the ozone layer. Further studies showed that a single chlorine atom will likely destroy between ten thousand and a hundred thousand ozone molecules.
Chlorine's potential for eliminating ozone is enormous. Efforts by various governments and organizations to do something about ozone-related problems are already underway. These efforts fall into two general categories. Attempts to eliminate low-level ozone pollution and attempts to slow the depletion of the upper ozone layer. The battle in the United States started back in the 1970 s when the EPA was formed in hope of helping prevent all the pollution across the world. The whole idea behind the EPA was to help all countries of the world eliminate the major environment problems; the one really major one was the depletion of the ozone layer.
The EPA first started in the United States and had a goal that by 1976 to have the whole country to meet a set standard for pollution. Not everyone was compiling with these standards so the deadline was extended to 1982. The plan was to have a catalytic converter which would go on passenger cars. As the exhaust passed through the catalytic converter a chemical reaction would take place removing the pollutants that would exit the muffler of the car and enter into the atmosphere. Amazing, after just five years, in 1987, across the country all reports of pollution was down in all urban areas. But the efforts werent as good as everyone expected, the amount of pollution in rural areas had greatly increased, this confused scientists for quite awhile.
It seemed that the converters werent removing the nitrogen oxides from the exhaust of fuel burning vehicles, and the wind carried the oxides far out into the countryside. These nitrogen oxides mixed with the hydrocarbons given off by trees and that created tons of low-level ozone, for the poor country folk to deal with. The EPA had yet again to deal with the problem they have now come up with new standards and all cities Worldwide must comply with. All cars must be equipped with a converter that will remove nitrogen oxides before releasing the exhaust into the air and that industrial companies most install state of the art converters on all hatches that lead chemicals into the atmosphere to remove any chlorine that might escape.
These new standards must be met by the year 2010 any disobeying Countries or Cities will be forced to pay panties. About the upper-level ozone, not that much can be done by use seeing's how the earth naturally created that protection barrier against ultraviolet rays. All industrial, the small businessman, and individuals alike have to take their part in saving the ozone, our planet, us and even our future generations. If we give the ozone a break it will eventually rejuvenate itself and return back to normal but it will take time, so be smart about what you do, install a clean burning converter on your car, and ensure many healthy generations to come.
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Research essay sample on France And Great Britain Ultraviolet Rays
