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).

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

Information on UVA, UVB and UVC 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 www.who.int/uv/en

Related Information on this website

Protecting Children from the SunThis website tells how to protect children from ultraviolet radiation when outside. Useful tips include finding shaded areas in which to play, appropriate clothing for protection, and how to apply sunscreen.
Basic Information about Skin CancerThis website lists basic information about the health effects of ultraviolet radiation and the differences between UVA, UVB, and UVC.
Excite Skin Cancer ModuleThe CDC website Excite provides public health topics for school-aged youth. The section on UV radiation and its intensity is part of a 14-module practice exercise series about skin cancer. The electromagnetic spectrum is also discussed, providing insight on electromagnetic waves and ultraviolet light.

For additional information about the Excite Skin Cancer Module, click here to go through all of the practice exercises in the skin cancer and ultraviolet radiation module.

National Institution for Occupational Safety and Health (NIOSH): Hazards to Outdoor Workers - UV RadiationUV radiation and outdoor workers, sunburn symptoms, and first aid tips are among the subjects in this website. NIOSH also has recommendations for protection from UV radiation that employers can distribute to workers who generally perform their duties outdoors.
Travelers Health –Yellow Book: Chapter 2, The Pretravel Consultation SunburnThis website specifically concerns travelers. Among the subjects considered are overexposure to the sun, health risks from UV rays, and preventive actions that travelers can take to avoid overexposure.

Related Sources

United States Environmental Protection Agency (EPA) : Sunwise Program This is an overview of EPA's Sunwise Program geared toward children and their caregivers. The website also provides additional resources about ultraviolet radiation.
United States Food and Drug Administration (FDA): Radiation-Emitting Products--Tanning Devices The FDA examines UV safety and radiation-emitting products such as tanning devices. On this site, the FDA provides some information on how tanning devices work and considers specifically the health risks posed by tanning procedures.