Ultraviolet A radiation, which can pass through window glass and clouds, causes changes to skin cells that may lead to cancer, a new study shows.
Experts once thought that UVA rays, sometimes called “aging rays” because they penetrate skin most deeply and lead to wrinkles, were less dangerous than UVB, or “burning rays,” which act primarily on the outermost layers of the skin where most cancers occur.
UVA rays are further divided into UVA1, the rays with the lowest energy that account for about 75% of visible sunlight, and UVA2. UVA is also the main kind of radiation used in tanning beds.
“People have really not been that concerned with UVA1 in the past. They’ve been more concerned, in the UVA spectrum, UVA2, which is closer to UVB,” says Darrell S. Rigel, MD, a clinical professor of dermatology at New York University Medical Center.
The new study shows that “with the UVA1 they were able to produce the same types of DNA damage that you see in early skin cancer, and that’s actually interesting because that hasn’t really been shown before,” says Rigel, who was not involved in the research.