Does the addition of the reflecting sun change the exposure time for getting a sunburn?
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 sunburn 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 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 only about five percent of light when the sun is high, but the shiny
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 45º, but
those rays, filtered through more atmosphere, are much weaker.