The front windshield of your car probably shields you from the sun's UV-A rays as you drive, but the same may not be true for side windows, a new study finds.
Experts have long known that prolonged exposure to ultraviolet A (UV-A) rays can raise the odds for skin cancer and cataracts.
And with the long hours many Americans drive each day, one researcher in California wondered how much sun protection today's cars might offer.
To find out, Dr. Brian Boxer Wachler, of the Boxer Wachler Vision Institute in Beverly Hills, analyzed the ultraviolet protection provided by the glass in 29 cars from 15 different automobile manufacturers.
Boxer Wachler measured levels of ambient UV-A radiation behind the front windshield and behind the driver's side window of the cars, which were produced between 1990 and 2014.
While windshield windows tended to offer good protection against UV-A, protection was lower and inconsistent for the side windows of cars, the study findings showed.
The study found front windshields blocked an average of 96 percent of UV-A rays, compared to 71 percent for side windows.
Overall, only 14 percent of the cars offered a high level of side-window UV-A protection, the research revealed.