Article stats: Views: 1805 Votes: 0 Average: 0.00 Added: 2003-12-17 Updated: 2006-11-17 | |
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Since about the mid-1990's, something new was added to our daily TV, radio, and newspaper weather reports - the UV Index. It has been instigated in an effort to halt the epidemic of skin cancer caused by increased sun exposure in recent decades. Long-term exposure to UV rays also contributes to cataracts and other eye problems.
The index is intended to alert you to take extra precautions - wear sunscreen, sunglasses, and a hat - on the days when the sun is most intense. Most important, a high reading on the Index will warn parents to protect their kids from the sun. It's estimated that by age 18, on average, people have been exposed to 80% of the lifetime UV radiation. The damage is cumulative, and the ill effects usually don't appear for decades.
Based on satellite measurements, or from data obtained from ground-based meters across the country, the Index reports the UV strength at noon at various locations nationwide. The scale ranges from 0 to 15. The following Index values equate to the corresponding exposure levels:
0-2 minimal
3-4 low
5-6 moderate
7-10 high
more than 10 very high
In Chicago, for instance, the readings would usually be 8 to 10 on a clear day in August; in Miami, 11 to 13. The Index takes into consideration the effect of ozone depletion, which increases UV levels, as well as clouds, haze, and pollution, which block some (but not all) UV rays. It's estimated that a fair-skinned person would burn in less than 13 minutes when the Index is "very high", in 13 to 20 minutes when "high;" in 20 to 30 minutes when "moderate," in 30 to 60 minutes when "low," and in more than an hour when "minimal." If your skin is darker, you can tolerate higher exposures.
The information provided concerns mostly UVB rays, which causes sunburn and which varies in intensity during various seasons of the year. UVA is fairly constant throughout the year, and can damage our skin whether the weather is sunny or cloudy. The safest course is to use a sunscreen every day that is at least SPF 15 and contains zinc oxide, which will give good protection. Used in conjunction with a 10% glycolic acid preparation, you get a double benefit: the glycolic acid repairs sun damage that has already occurred, the sunscreen protects from further damage.
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