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TIME: Almanac 1990
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1990 Time Magazine Compact Almanac, The (1991)(Time).iso
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time
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070389
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07038900.034
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1990-09-22
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SCIENCE, Page 52The Sun's Dark Side
For all its beneficence, the sun is not too kind to those who,
intentionally or not, overexpose themselves to its warming rays.
While most of the harmful solar radiation is absorbed by the ozone
layer, enough ultraviolet light gets through the atmosphere to
endanger the unwary.
In addition to the occasional painful sunburn, long-term
exposure to the sun, especially between 10 a.m. and 3 p.m., weakens
the skin's elasticity and brings on premature wrinkling and
sagging. Of greater concern, it causes as many as half a million
new cases of skin cancer every year. Most of these are basal or
squamous cell carcinomas, which have high cure rates. But solar
radiation may be a cause of melanoma, which can be fatal.
Ultraviolet light apparently weakens the immune system; after a
severe sunburn, some people suffer outbreaks of oral herpes or
other disorders. Excessive exposure aggravates cases of chicken pox
and can be especially dangerous, even fatal, to victims of lupus.
Sunscreens with a skin protection factor SPF of 15 or higher
can minimize the risks to skin and the immune system. People who
have allergic reactions to the sun, in the form of hives, blisters,
red blotchy areas or bumps, may be using some drug, cosmetic or
perfume that makes them more sensitive to sunlight. Avoiding such
products will generally help solve the problem.
Ultraviolet rays have been implicated in the development of
cataracts, a clouding of the eye lens. The rays chemically alter
the lens' proteins, making them stick together and turning a clear
lens murky. For protection during long exposure to the sun, doctors
recommend wearing sunglasses, especially those that completely
block ultraviolet, and wide-brimmed hats.