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UV Radiation and Tanning

Understanding Ultraviolet Radiation

What it is

Radiation emitted from the sun is known as ultraviolet radiation (UVR), and reaches the earth in two forms:

  • Ultraviolet A (UVA) rays are long-wave and reach deeper into human skin layers
  • Ultraviolet B (UVB) rays are short-wave and damage the top layers of human skin

With even shorter rays than UVB radiation, UVC is absorbed by the ozone layer and does not reach the earth.

Light spectrum

What it does

UVR from the sun and tanning beds damages skin cells, causing genetic mutations that can lead to skin cancer. Both the U.S. Department of Health and Human Services (HHS) and the World Health Organization (WHO) have identified UVR as carcinogenic (cancer causing) to humans. 

ALL UVR

  • Causes skin cancer
  • Causes premature skin aging such as wrinkles, sagging, and age spots
  • Causes damage to the eyes, such as cataracts
  • Suppresses the immune system

UVA

UVR on skin
  • Penetrates and damages the deeper layers of skin
  • Passes through some fabrics, glass, and even some sunscreens  
  • Primarily causes skin tanning
  • Intensity is consistent year-round

UVB

  • Penetrates and damages the top layers of skin
  • Does not significantly penetrate most fabrics or glass
  • Primarily causes skin reddening and sunburn
  • Intensity varies by season-UVB is most intense from April-October, but can burn and damage your skin year-round 

Environmental factors that affect UVR

Time of day

UV levels vary mainly with the height of the sun in the sky. At midday (10-4pm), the sun's rays take the most direct path to earth. 

Latitude

UV levels are stronger at locations closer to the equator, where the sun's rays have a shorter distance to travel through the atmosphere. 

Altitude

Higher altitudes have less atmosphere to absorb UV radiation. 

Clouds and haze

Be careful not to underestimate the amount of UV radiation passing through clouds. While your skin may feel cooler on cloudy days, UVR is not related to temperature. Don't be fooled by an overcast day or a cool breeze!

Reflective surfaces

Many surfaces reflect UVR, making exposure more intense. Be aware of reflective surroundings such as:

  • Water
  • Sand
  • Concrete/granite
  • Glass
  • Snow

What to do

Protect yourself from UV radiation, both indoors and out!

  • Always seek the shade outdoors, especially between 10 AM and 4 PM
  • Wear sunscreen
  • Cover up with a wide-brimmed hat, sunglasses, long-sleeves and pants
  • AVOID TANNING in the sun and in tanning beds
  • Consider adding tinted UV-protective film to your car's side and rear windows as well as to house and business windows. This film blocks up to 99.9 percent of UV radiation

UV Index Scale

UV index chart

Pay attention to the Daily UV Index - the higher the number, the more you need to protect yourself from the dangers of UV overexposure.  

Check the UV index in your area!

Dangers of Tanning Beds

The World Health Organization’s International Agency for Research on Cancer (IARC) classifies UV tanning beds in the highest cancer risk category: "Carcinogenic to Humans." (1)

Whether you get a tan outside or in a tanning bed, you are exposing your skin to damaging UVR. Too much UVR causes skin cancer.

Tanning is your skin's natural defense against damaging UVR from the sun and tanning beds. Your skin darkens to try to block the rays from reaching deeper layers of your skin. The tanner you are, the more damage you are doing to your skin! 

Just one indoor tanning session increases a person’s chances of developing melanoma by 20 percent. (2)

Using a tanning bed before age 35 increases a person’s risk for melanoma by 75 percent. (3)

Tanning also causes:

  • Premature aging of the skin
  • Redness, blotches, or yellowing of the skin
  • Leathery skin, wrinkles and sagging skin
  • Freckles, age spots and liver spots
  • A weakened immune system

Tanning Myths Debunked

  • Indoor tanning is not safer than tanning in the sun. Both indoor tanning and tanning outside can cause skin cancer.
  • A base tan is not a safe tan. Any darkening of the skin is causing damage to skin cells, which can lead to skin cancer.
  • Indoor tanning is not a good way to get vitamin D. Eat a diet rich in vitamin D (milk, eggs, fish) and take a daily supplement if needed. 

Safer ways to look tan

  • Sunless tanning products
  • Professional mist-on or airbrush tans
  • Bronzers

For more information on indoor tanning, visit:

http://www.aad.org/media-resources/stats-and-facts/prevention-and-care/indoor-tanning

For the latest information on state laws for indoor tanning, visit:

https://www.aimatmelanoma.org/legislation-policy-advocacy/indoor-tanning

 

References

  1. El Ghissassi F, Baan R, Straif K, et al. Special report: policy. A review of human carcinogens—part D: radiation. The Lancet 2009; 10(8):751-752.​ http://www.iarc.fr/en/media-centre/iarcnews/2009/sunbeds_uvradiation.php
  2. Boniol M, Autier P, Boyle P, Gandini S. Cutaneous melanoma attributable to sunbed use: systematic review and meta-analysis. BMJ 2012; 345:e4757. doi: 10.1136/bmj.e4757
  3. Lazovich D, Vogel RI, Berwick M, Weinstock MA, Anderson KE, Warshaw EM. Indoor tanning and risk of melanoma: a case-control study in a highly-exposed population. Cancer Epidem Biomar Prev 2010 June; 19(6):1557-1568.
  4. World Health Organization ( http://www.who.int/uv/faq/whatisuv/en/)
  5. Skin Cancer Foundation (http://www.skincancer.org/prevention/uva-and-uvb)