NDSU Extension - Sargent County


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Sun Smart

The most common cancer in the United States is skin cancer. However, risks for developing it are reduced when we make sun-safe choices.  One choice is to apply sunscreen (SPF 30 or higher) 20 minutes before sun/outdoor exposure, and to reapply it every 2-3 hours.  Other proactive choices include the decision to wear hats, clothing and UV protective sunglasses, to seek shade to cool off, and to limit alcohol consumption because it increases the likelihood of sunburn.

The sun’s ultraviolet (UV) rays are the culprit for causing health risks for us.  Sunlight contains three types of ultraviolet rays: UVA, UVB, and UVC.  UVA rays cause skin aging and wrinkling, and contribute to skin cancer, such as melanoma.  They make up the majority of our sun exposure.

Tanning beds use UVA rays to generate tanning.  A UVA tan does not help protect the skin from further sun damage; it merely produces color and a false sense of protection from the sun.

UVB rays are also dangerous. They contribute to cancer because they cause sunburns and cataracts, and damage the immune system.  Melanoma, the most dangerous form of skin cancer, is thought to be associated with severe UVB sunburns that occur before the age of 20.  Most UVB rays are absorbed by the ozone layer in the earth’s atmosphere, but enough of these rays pass through to cause serious damage.

UVC rays are the most dangerous, but fortunately, these rays are blocked by the ozone layer and don't reach the earth.  However, the ozone layer has thinned since when our parents, grandparents and great grandparents were kids, so it offers less protection than it did years ago.

Sunglasses can offer excellent protection for your eyes.  Shop for sunglasses with lenses that are labeled to block out 95% of UV.  Polychromatic or colored glasses are not as effective in blocking out UV.  Polarizing lenses will reduce glare substantially, but polarization itself has little effect on the UV-absorbing properties of lenses.  Similarly, mirror finishes by themselves do not significantly reduce UV absorption.  Even children should use sunglasses properly and consistently, but you’re never too old to start using them!  People who wear corrective eyeglasses should add UV-protective coating, attach protective clip-ons, or obtain prescription sunglasses.

As for sunscreen skin products, ND Cancer Coalition recommends choosing products with sun protection factor (SPF) of 30 or more.  Oklahoma State University Environmental Health and Safety training modules advise:

  • No sunscreen offers 100% protection from the sun’s damaging UV.  UV will still get through to the fragile upper and lower layers of your skin.
  • Sunscreen should always be used in conjunction with other forms of protection like hats, sunglasses, clothing and shade.
  • Sun protection factor (SPF) of 30 or more blocks out 96% of UV.  Products with SPF 15+ will block out only about 93%.
  • Using SPF 30+ instead of SPF 15+ does not mean you can safely double the amount of time you spend in the sun.  Never use sunscreen to extend the amount of time you would normally spend in the sun.
  • For sunscreen to be effective at protecting you from sunburn, slop it on 20 minutes before going outside so that the protective elements in it have time to bond to your skin.  Don’t rub it in--a light film should stay visible.  Remember to reapply every two hours or more regularly if swimming or sweating a lot.

For additional information on the topic of sun safety, contact the NDSU Extension Service.

Sources:  http://ehs.okstate.edu/modules/sun/guidelines.htm and http://tnmilitary.org/pdfs/101_Critical_Days_of_Summer.pdf


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