Sun exposure through car windows can be harmful

If your family travels by car (more than 89 percent of travel during the summer is by car), you could inadvertently expose your children or yourself to harmful ultraviolet A (UVA) rays, a known cause of skin cancer. Because window glass protects against ultraviolet B (UVB) rays which cause sunburns, many people don’t realize they are still being exposed to UVA rays that penetrate deep into the skin—the same rays that cause interiors to fade and crack over time.
UVA rays penetrate glass every day of the year, even when it’s cloudy, and most standard and privacy glass side and rear windows of vehicles do not provide adequate protection. In fact, glass can reflect the sun’s rays, possibly intensifying harmful effects.

A 2010 study from St. Louis University Medical School revealed that nearly 53 percent of skin cancers in the U.S. occur on the left side of the body, the side of a driver most exposed to the sun’s rays. Researchers believe there is a correlation with exposure to UVA radiation while driving because in countries such as Australia where drivers sit on the right side of the car, the trend is reversed.

Not only is the likelihood of skin cancer increased by inadvertent sun exposure, but a driver’s face will show more wrinkling, leathering, sagging, and incidence of brown age spots on the left side. The more time spent behind the wheel (or seated behind the driver), the more severe is photodamage on the left side, reports Susan Butler, MD, a dermatologist and micrographic surgeon at the California Institute.

If you make sure your kids apply sunscreen when playing outside, keep in mind that sun exposure happens when they ride in the car, too—especially by the left window. A generous slather or spray of sunscreen can minimize harmful effects of sun exposure.

Another relatively inexpensive solution is applying a window film, which can be clear for greater visibility or darker for privacy. When looking for a window film, ask if it has earned the Skin Cancer Foundation’s Seal of Recommendation.

Long term, it pays to be safe inside your car as well as outside.