Dear Tom,
While sailing on Lake Michigan, the sun is both overhead and reflecting off the water on a sunny day. Does the addition of the reflecting sun change the exposure time for getting a sun burn on water versus on land?
–Gerald Migely, Chicago
Dear Gerald,
“The higher incidence of skin cancers in sailors and farmers was one of the first clinical clues that ultraviolet (UV) radiation is a carcinogen,” said Dr. Bryan Schultz, an Oak Park dermatologist. “Most of the risk for sailors is in the long exposure times, but the percent of UV reflected is also a factor.”
Water reflects about 5 percent of light when the sun is high, but the surface of a boat may approach 80 percent. “This does increase one’s UV dose significantly,” Schultz said. UV reflection increases as the sun drops below 45 degrees, but the rays, filtered by more atmosphere, are weaker.
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