The sun emits two kinds of ultraviolet rays that can damage skin; the long UVA causes primarily aging and the short UVB rays cause primarily basal cell skin cancers and sunburns, but all ultraviolet rays can cause sunburns, skin cancers, wrinkling and aging. Applying sunscreen every day and staying out of the sun can even help to reverse precancerous changes in the skin that are already there.
Sunscreen and Tanning Myths
- Glass windows do not block all ultraviolet rays. Glass blocks most of the short UVB rays, but only 30% of the UVA rays, so windows prevent sun burns, but they do not prevent aging and wrinkling.
- Tanning booth salon lights are advertised not to cause cancer because they emit primarily UVA rays and not UVB. But, UVA causes cancer, wrinkling and aging, even though it is less likely to cause burns.
- Sunscreens do not prevent cancer; They do block most of the UVB and some of the UVA so sunscreens prevent burns, but they are minimally effective in preventing wrinkling and aging.
- Most shirts allow some UVA rays to reach your skin, so wearing a shirt markedly decreases your chances of being burnt, but long periods in the sun with most shirts can still increase your chances of wrinkling and aging.