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Wednesday, February 24, 2010

What are chlorofluorocarbons? What are their various classes and how are these harmful to environment?

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Pollution through radiation Pollution produces serious consequences. Exposure to radiations causes damage to tissues and organs and produces permanent effects. Some radiations persist for longer periods and cause cancer leading to death. Some radiations cause injuries and tumours that too are proved to be fatal after some times. Radiations cause sudden but permanent changes in bodies of organisms that are inherited. A number of genetic diseases are caused due to mutations resulted by exposure of body parts to specific radiations.
Compounds of chlorine, fluorine and carbon are called as chlorofluorocarbons or CFCs.

In fact, these are aliphatic organic compounds. These were first developed in 1930 and were started to be considered as ‘Miraculous Refrigerants’. Scientists in the Frigid Air Division of General Motors in the United States discovered Freon-12 to use in the place of methyl chloride, ethyl chloride, propane, and sulphur that were used as refrigerants during that period. Since, these compounds were inflammable and toxic; Freon and Genetron came to be used on large scale after 1930. After the development of low pressure valves, these chemicals became ideal propellants for dispersing aerosols. Du Pont, the U.S. Company, developed a series of chlorofluorocarbons for the application as propellants, cleaning agents, plastic foams, fast food packaging materials, dry cleaning industries, sterilization of surgical instruments and for degreasing electronic equipments.

Some of the major classes of chlorofluorocarbons are – Difluoro dichloro methane (CF2Cl2), Fluorochloro methane (CFCl3), Dichloro fluoromethane, Trichlorofluoromethan (Freon-12), Freo-22, Freon-114, and Freon 115. These chlorofluorocarbons can be classified as methane based, ethane based, and Halon chlorofluorocarbons.

As every one of us knows today, CFCs contribute to the global problem of causing the depletion of Ozone layer, the umbrella of the mother earth that protects life against the Ultra Violet Radiations coming from the outer space.

These ultraviolet radiations if allowed to reach to the earth can cause seriously harmful effects on the earth’s environment. On the first place these can cause cataract in human eye when exposed. On the second place these radiations can cause skin problems and even these can lead to skin cancer it the skin is frequently exposed for long durations. These are efficient enough to kill germs and even bacteria on earth including the useful ones.

Ultraviolet radiations can cause chlorosis in leaves and reduce the rate of photosynthesis causing serious losses to productivity and can even lead to death of plants. It is further reported that certain red algae loose their red colour due to the effects of ultraviolet light.

Image : Some Red Algae loose their red colour due to the impact of Ultraviolet Radiation

It is reported by researchers that prolonged human exposure to solar ultraviolet radiation may cause acute and chronic health effects on skin, eye, and human immune system. Erythema or the sun burn is well known effect of ultraviolet radiations. These radiations cause degenerative impacts on skin, fibrous tissues and even to blood vessels that may lead to premature ageing of skin, photodermatoses, and actinic keratoses.

Inflammatory reactions to human eyes are well known health impact of ultraviolet radiation. This condition leads to cataract of eyes and even skin cancer in some cases. Each year the doctors diagnose between 2 to 3 million non-melanoma skin cancers for example basal cell carcinomas, and squamous cell-carcinomas. However these may rarely be fatal and can be cured through surgery. Each year about 130,000 malignant melanomas have been reported to occur on the global scale each year. Melanoma and other skin cancers have been reported to cause death on global scale up to an estimated number of 66,000.Over 65,000 cases of skin cancer were reported fro U.K. alone. Here the number of skin cases has more than doubled since early 8os. Also, about 2,000 people die here from skin cancer each year.

About 12 to 15 million people become blind from cataract worldwide out of which 20 percent may be caused or activated by the exposure of sun as per the estimates of the World Health Organisation (WHO).It has also been reported by researchers that environmental levels of ultraviolet radiation may suppress cell-mediated immunity and thereby enhance the risk of infectious diseases and limit the efficacy of vaccination. These impacts are especially seen on poor and vulnerable people, especially children of the developing world. Since, many developing countries are located close to equator; people in these areas are exposed to high levels of ultraviolet radiation that reaches to these regions from the sun.

Key Words:Radiation, Ultraviolet radiation, chlorofluorocarbons,WHO, chlorosis, immunity, skin cancer, cataract, equator

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