While it's understood that taking sun safety precautions during the summer months is a must, many people don't realize they need to protect their skin year-round - even when indoors. The temperature may drop and the sunlight may be less intense, but the amount of ultraviolet (UV) solar radiation that reaches earth remains very strong, even during cooler weather.
While ultraviolet B (UVB) rays, the main cause of sunburn, are the strongest in the summer, ultraviolet A (UVA) rays remain constant throughout the year. UVA rays account for up to 95 percent of the UV radiation reaching the Earth's surface. Although they are less intense than UVB, UVA rays are 30 to 50 times more prevalent, and go through glass, making sun protection necessary indoors as well as out.
"Our knowledge of the dangers associated with the sun's longer-wave UVA rays has grown significantly over the last few decades," said Perry Robins, MD, President, The Skin Cancer Foundation. "We now know that UVA radiation can penetrate windows to reach the skin, accelerating skin aging."
The need for sun protection indoors was reinforced in a recent report published in Clinical Interventions in Aging. Eight women and two men had significantly more wrinkles, brown spots, and sagging skin on one side of the face, even though they worked indoors. The side of the subjects' faces that was regularly closer to a window exhibited more signs of sun damage ("asymmetrical facial damage"), and UVA rays are believed to be the culprit. While both UVA and UVB rays can harm the skin and lead to skin cancers, UVB is effectively blocked by glass. However, at least 50 percent of UVA radiation can pass through windows. (Car windows have been proven to let in more than 60 percent.) This is important news for people who habitually sit near a window - whether at work, at home, or during a long commute by car, train, or bus.
Everyday Sun Protection
Be sure to use a broad-spectrum sunscreen with an SPF (Sun Protection Factor) of 15 or higher and one or more of these UVA-protective ingredients: avobenzone, ecamsule, oxybenzone, titanium dioxide, and zinc oxide. Window film, which can be applied to home, office and car windows, blocks almost 100 percent of UVA and UVB radiation.
Winter Sun Protection Tips
Use a broad-spectrum sunscreen with an SPF of 30 when spending extended time outdoors, and don't forget areas such as underneath the nose and chin. Snow reflects up to 80 percent of the sun's UV light, so the rays hit you twice, further increasing your risk of skin cancer and premature aging. Wear protective clothing such as a broad-brimmed hat, gloves and UV-blocking sunglasses with wraparound or large frames. Also, reapply sunscreen every two hours, and immediately after sweating or significant exposure to wind and snow which can wear away sunscreen. Activities such as skiing and snowboarding call for just as much sunscreen as you would use at the beach, since UV exposure increases 8 to 10 percent with every 1,000 feet above sea level.