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Politics : PRESIDENT GEORGE W. BUSH -- Ignore unavailable to you. Want to Upgrade?

To: GROUND ZERO™ who wrote (731198)	3/12/2006 1:33:15 PM
From: CYBERKEN	Read Replies (1) \| Respond to of 769670

"All science is political now."---V. Lenin...

To: GROUND ZERO™ who wrote (731198)	3/12/2006 2:13:33 PM
From: puborectalis	Read Replies (2) \| Respond to of 769670

If you've ever had melanoma(a deadly skin cancer) or a mole that's changed shape or color then read this: Because CFCs are not destroyed in the lower atmosphere, they drift into the upper atmosphere. In the stratosphere, CFCs come in contact with Ultra-Violet (UV) radiation from the sun. The CFCs are broken down by the UV radiation and cause chlorine atoms to be released. Once the chlorine atoms are free, they react with existing ozone (O3) forming chlorine oxide. This process upsets the natural balance of photochemical reactions, thus causing ozone depletion. (iii) CFCs contribute to over 80 percent of ozone depletion. It takes about a decade for the chemicals to reach the stratosphere. Once CFCs reach this level, they cause reactions with the ozone which last between 75 and 110 years. One molecule of CFC has the ability to destroy 100,000 molecules of ozone. (iv) The natural layer of ozone in the stratosphere is important to be maintained because it shields the earth from harmful levels of UV radiation. It took millions of years to accumulate a sufficient amount of ozone to screen out the this UV radiation coming from the sun. However, due to the use of man-made products containing CFCs, significant amounts of damage to the ozone layer has occurred. (v) Ozone depletion due to CFCs is not a hypothesis, it is a fact. Using the paleorecord, such as Antarctic ice cores, scientists have measured the levels of chlorine concentration in the atmosphere from various periods. Pre-industrial periods revealed that chlorine concentrations were less than 1ppbv (parts per billion by volume). By 1989 the level had rose to 3.6 ppbv. (vi) As the ozone is reduced by 1 percent, the UV-B radiation on the surface of the earth increases by 2 percent. (vii) Ultraviolet radiation makes up a part of the electromagnetic spectrum and has wavelengths shorter than light visible to humans. One source of UV radiation comes from the sun. UV is usually split into three bands, UVA, UVB, and UVC. UVC is very dangerous to humans, however it is absorbed completely by oxygen (O2) as well as ozone. UVA is not absorbed by ozone at all. However, UVB is the most damaging form of UV radiation to humans when it is not kept in check by ozone. UV-B can cause skin cancer, particularly melanoma. (viii) UV-B radiation damages cancer-suppression genes in skin cells, causing tumors. UV-B also promotes the continued growth of tumors. UV-B levels remained at a fixed point for generations, and skin cells were able to combat the negative affects of these UV-B levels through repair mechanisms within the cells. However, as UV-B levels increased the ability of the mechanisms to fight UV-B damage was reduces, allowing tumors to form. It is estimated that a 1 percent increase in UVB would result in a 2 percent increase in skin cancers of light-skinned people. (ix) UV radiation damages a staggering amount of DNA molecules within each cell. On average between 100,000 to 1,000,000 areas in the DNA structure are damaged on one typical sunbathing session. When the DNA is unable to repair itself, it may make an incorrect copy of itself and cause the entire cell to grow into an independent tumor or cancer. (x) Non-melanoma skin cancer is now the most common form of cancer in light-skinned populations, and it is rising at a faster rate than any other form of cancer. Over 600,000 cases are diagnosed each year within the United States. While this form of cancer is easily detected and treatable, 1 percent of all cases are lethal. (xi) Melanoma, or skin cancer of the pigment cells, occurs at a much lower rate. It appears as wart-like tumors, reddish in color. Caught early, these tumors can be cured by surgical removal. But once the malignancy spreads to other parts of the body, it is among the most deadly and fastest spreading forms of cancer. Only an average of 29,000 cases are diagnosed each year. While there is still much scientific debate over the effects of ozone depletion as a primary cause of melanoma, UV-B radiation can increase the rate of growth of melanoma cancer. (xii) UV-B radiation also limits the body's immune systems that fight cancer, thus making the body susceptible to all forms of cancer and infections. (xiii) This has been proven through laboratory experiments with mice. A tumor which is implanted onto a mouse which has not been exposed to UV radiation is rejected. However, once the mouse is subjected to UVB, the implanted tumor cells are accepted and allowed to grow. Thus, UVB takes away the natural ability to fight off the cancer. (xiv) As a result, the dangers of CFCs have been recognized. In 1987, 27 nations signed the Montreal Protocol to Reduce Substances that Deplete the Ozone Layer. Also, in the United States, the Clean Air Act now prohibits the release of CFCs into the air in America. The use of CFCs will become obsolete within the next decade. Currently, no more CFCs are being produced. Only recycled CFCs are available. Substitutes such as hydrochlorofluorocarbons (HCFCs) and the hydrofluorocarbons (HFCs) are available. (xv)