While most people can not get sunburned through a window, that doesn't mean that glass protects you from all of the harmful effects of the sun. Glass commonly blocks UVB rays, butuntreated windowsdo not shield you from dangerous UVA rays.
Despite many health organizations' efforts to clarify the difference betweenUVB and UVA rays, people are still confused and believe they're safe and healthy as long as they don't get a burn or stay outdoors too long.
UVBandUVA rays: What's the difference?
UVB rays cause sunburn. It's easy to tell if you've been overexposed by the redness and pain. The effects of UVA rays are more insidious and cause damage over the long term.
They don't impact the skin right away -- instead, after years of exposure, UVA rays increase signs of visible aging such as wrinkles and brown spots, and can also lead toskin cancer, includingmelanoma, the most deadly form. While UVB rays can also lead to cancer and photo-aging, they diminish during the winter. UVA rays are present, and harmful, year-round.
Drivers are particularly vulnerable
UVA rays can penetrate a typical window -- whether it's in your home, office, or school. Because car windows are located so close to the body, they pose a particular risk.
Car windshields are coatedwith a protective film that blocks UVA rays, but often, side windows are not. At least two studies have shown that commuters and others who spend a lot of time in the car have an increased risk of developing skin cancer on the left side of their bodies -- the side that gets the most exposure through the car windows for U.S. drivers.
In the first study, led by Dr. Scott Fosko at theSt. Louis University School of Medicineand published in 2010, researchers combed through the records of more than 1,000 patients treated by a local skin cancer clinic. They discovered that the people who spent the most time driving were more likely to develop cancers on their left sides, especially on their faces, necks, arms, and hands -- areas exposed to sunlight through the side window. According to Dr. Fosko, "It is an exposure that the public most likely doesn't consider and should be aware of and take precautions with."
Dr. Fosko suggests that if you are regularly sitting beside a sunny window indoors, you should also protect yourself from exposure to UVA rays. Although the chronic effects take several years to develop, he warns, "The damage starts early."
How to protect yourself:
Consider having your car's side and rear windows tinted or laminated with aUV-filtering materialsuch as UV film.
Roll up your car windows -- open windows let in even more UVA rays as well as UVB rays.
Drive wearing long sleeves.
Install a rear window and passenger side windowsun shadesto protect your children.
Consider usingUV film on home or workplace windows. It is readily available at building supply stores. In addition to blocking harmful rays, it also helps prevent curtain and upholstery fabrics from fading.