Monday's sun safety tip pointed to sunglasses as a means of protecting the eyes from the sun. Today's tip brings to light a broader and more obvious tool for sun protection: sunscreen. Sunscreens are products applied to the skin for protection against the sun's ultraviolet (UV) rays. These UV rays can damage your skin in as little as 15 minutes.

UV radiation has three wavelength ranges:

  • UVA rays - these age cells and may damage cell DNA. Linked to long-term skin damage such as wrinkles, they are thought to play a role in some skin cancers.
  • UVB rays - these can directly damage DNA and are the cause of sunburns. Scientists believe they cause most skin cancers.
  • UVC rays - these don't get through our atmosphere.

Sunscreen conveniently comes in many forms - lotions, creams, ointments, gels, sprays, wipes, and balms. Some cosmetics, such as lipsticks and foundations, also contain sunscreen. Put on sunscreen before you go outside, even on slightly cloudy or cool days. Apply a thick layer on all parts of exposed skin and remember to reapply if you stay out in the sun for more than two hours. After sweating or swimming, reapplication is also necessary.


Sunscreens are assigned a sun protection factor (SPF) number that rates their effectiveness in blocking UV rays. SPF 15 sunscreens filter out about 93 percent of UVB rays, while SPF 30 filters out about 97 percent, SPF 50 about 98 percent, and SPF 100 about 99 percent. It is recommended you use a sunscreen with at least SPF 15 and remember to check the expiration date before purchasing.

Most sun protection products work by absorbing, reflecting, or scattering sunlight. They are not chemically identical, so if your skin reacts badly to one sunscreen product, simply try another with different ingredients. If you have a serious reaction, notify your doctor.

Don't forget that children need sunscreen, too.

  • Ask a health care professional before applying sunscreen to children under six months old.
  • Apply sunscreen to children older than six months every time they go out.