No, you can't get sunburned if your window is rolled up while you drive—car window glass blocks the ultraviolet rays that cause sunburn. Can you sustain long-term skin damage nevertheless? Absolutely. This striking photograph from a recent article in the New England Journal of Medicine provides a startling example of the risks of ultraviolet light—and highlights the importance of selecting a sunscreen that protects you from the full spectrum of UV rays:
What's going on here? This is one Bill McElligott, 69, a delivery truck driver of 28 years, who has sustained severe sun damage to the left side of his face from years of sun exposure through the driver-side window.
The basic reason is this: Essentially, ultraviolet (UV) rays come in two varieties: UVA and UVB. UVB is the one that causes sunburns (think "B" for "burn"). UVA does not cause sunburn, but does cause long-term skin damage and premature wrinkling and aging of the skin (think "A" for "aging"). Most glass, including car window glass, blocks UVB, but not UVA. (Windshields, on the other hand, are usually treated to block both UVA and UVB.)
Mr. McElligott's face shows the long-term risks of prolonged exposure to UVA—a hazard well worth protecting yourself from anytime you're outdoors and exposed to the sun.
The obvious answer, of course, is to apply sunscreen. But here's the kicker. SPF, the most commonly-used reference for a sunscreen's efficacy, only applies to protection from UVB. It has no bearing whatsoever on whether a sunscreen blocks UVA. To determine whether a sunscreen is shielding you from both harmful varieties, you'll have to do your own research because no standard currently exists in the U.S. for sunscreen labeling for UVA protection.
I highly recommend the 2012 Sunscreen Guide from the Environmental Working Group to help you find a sunscreen that provides the protection you need.
Stay pale. Stay young. Shop smart the next time you buy sunscreen!
Learn more about sunscreens and UV from these recent posts and articles:
Code Red: Pale is the new tan (2008)
The Best Sunscreens (2011)
How Much UV Radiation Does Snow Reflect? (2011)
Dermatone Sunscreens (2010)
Best & Worst Sunscreens (2010)
Super Sunscreen: Vertra Elemental Resistance (2009)
“Equipped” is an AMC Outdoors blog, written by Matt Heid.
Labels: Sun Protection