New study suggests skin cancer-related UV rays can get through vehicle side window

By Ryan Johnson

FARGO—We all know the drill: Put on sunscreen if we’re going to enjoy a sunny day outdoors.
But we might want to apply that sunscreen long before we get to our summer destinations, according to a new study that found a type of sunlight associated with skin cancer and cataracts can make its way through car windows more easily than might be expected.
The study, published earlier this month in the JAMA Ophthalmology journal, analyzed 29 makes of vehicles from 15 manufacturers with model years from 1990 to 2014. By measuring the amount of ultraviolet-A radiation, researchers found not all windows are equal.
Windshields blocked an average of 96 percent of UV-A rays, while side-window blockage averaged 71 percent. One vehicle stopped only 44 percent of these rays.
It could be cause to think twice about how protected we are inside a closed car, but local experts say there are steps that can minimize our sun-damage risks while driving down the highway.

More UV, more problems

David Flach, a dermatologist at Sanford Dermatology and Laser Clinic in Fargo, said ultraviolet light comes in three varieties. UV-B rays are responsible for sunburns, he said, but car windows will typically block out this shorter wavelength light, meaning it’s unlikely drivers or passengers will get a sunburn inside a closed vehicle.
That’s not the case with the longer wavelengths of UV-A, as found by the study.
Flach said previous studies have hinted at this potential issue, including the finding that Americans who spend a lot of time in the car will have more sun damage, skin cancers and cataracts on the left side of their face, while the reverse is true in countries where the driver’s side is on the right.
More exposure to UV-A seems to correlate to a greater chance of developing problems, especially melanoma, he said…….
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Source: Inforum