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Ultraviolet Radiation

Key Points:

  • Ultraviolet radiation—or UV radiation—comes from the sun. In addition to the sun, electric lights, black lights, and tanning lamps release UV radiation.which is also a form of non-ionizing radiation.
  • UV radiation can pose health risks. These risks include sunburn, suntan, premature aging, cataracts, and skin cancer.
  • Scientists divide ultraviolet radiation into three primary groups (or wavelengths): ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC).


Information on UVA, UVB and UVC radiation

Radiation can naturally come from the sun through ultraviolet (UV) radiation

Radiation can naturally come from the sun through ultraviolet (UV) radiation

  • The Earth’s ozone layer absorbs most of the UVB and UVC radiation from the sun. Although nearly all ultraviolet radiation received on earth is UVA, some UVB rays get through as well.
  • UVB affects the skin’s outer layer.
  • UVA radiation, while weaker than UVB, penetrates deeper into the skin and is often more constant throughout the year, regardless of the weather.
  • UVC radiation does not pose as much of a health risk as UVB.


UV radiation can also be helpful. UV radiation produces vitamin D, which helps the body absorb calcium and phosphorus from food and assists in bone development. To get enough vitamin D, the World Health Organization (WHO) recommends 5 to 15 minutes of sun exposure 2 to 3 times a week. More information is available at


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