TOO MUCH SUN-NOT A BRIGHT IDEA

Many people find deep, rich suntans attractive and desirable. Accordingly, they expose as much skin as possible to natural or artificial sunlight. Unfortunately, sunburns occur almost as commonly as suntans. There is also mounting evidence that exposure to the sun's rays over a long period of time may result in skin cancer. The American Academy of Dermatology estimates that 1 in 5 people will get skin cancer in their lifetime. The main culprit is repeated exposure to ultraviolet rays.

Although the stratospheric ozone layer absorbs most of the short-wave ultraviolet (UV) radiation that is extremely harmful, plenty of UV rays of longer wavelengths (above 285 nm) reach the earth's surface. Long-wavelength ultraviolet radiation in sunlight causes both suntans and sun-burns. Most of the radiation is absorbed by melanin, a skin pigment. Carefully limited and repeated exposure to sunlight results in the production of more melanin, which gradually darkens the skin.

The sun's rays that cause tanning or burning can be blocked by clothing or an umbrella or opaque materials such as zinc oxide(white) in a cream formulation. Several popular lotions contain p-aminobenzoic acid (PABA), which like other benzene compounds absorbs UV radiation and so acts as a sunscreen.

p-aminobenzoic acid

However, PABA absorbs more of the UV rays that tend to cause burning than the slightly longer wavelength rays that tend to cause tanning. Thus, the skin tends to tan without burning. In some lotions. the concentration of PABA is indicated by skin-protection factor (SPF) ratings. Those having larger numbers contain higher concentrations of or other UV-absorbing components and thus protect more effectively against sunburn.

Like the sun, sunlamps also give off UV radiation and can be harmful. Exposure to UV radiation from sunlamps adds to the total amount of UV radiation your skin accumulates during your lifetime, and increases the risk of skin cancer. According to the Food and Drug Administration (FDA), tanning devices are not recommended for anyone.