UVA rays are long wave solar rays. While they have less energy than UVB rays, they can penetrate the deepest layers of skin and cause damage such as wrinkles and age spots. The cumulative damage of UVA rays breaks down the collagen and elastin in the skin. They are less likely to play a role in severe sunburns.
UVA rays make up a majority of the sun’s ultraviolet light and can penetrate clouds, windows, light colored clothing, and windshields. UVA rays are used in tanning beds. They also help the body produce vitamin D.
While shorter in wavelength, UVB rays are more potent and are responsible for sunburns and are a primary culprit in skin cancer. UVB rays stimulate melanocyte cells to produce melanin, the substance responsible for skin pigmentation. UVB rays do the most damage during the peak heating of the day, typically 10 a.m. to 4 p.m.
UVA/UVB and Skin Cancer
Much of the focus has been on UVB rays, but recent research also shows UVA rays contributing to the development of skin cancer. Think about this – most tanning beds use UVA rays. Tanning causes cumulative damage to the skin over time. A tan results from injury to the skin’s DNA. Repeat this process each time you visit a tanning bed. These mutations in skin’s DNA can eventually lead to skin cancer.
Protection from both UVA and UVB rays are optimal to in preventing skin damage and skin cancer. This includes covering exposed areas of skin and using sunscreens while outside.