What is UV Radiation

Ultraviolet (UV) light is energy that is a part of the electromagnetic spectrum, an all encompassing range of electromagnetic radiation. The wavelength of UV is found within the 10-400 nanometer range. Most UV radiation on the Earth comes from the sun, but UV lights are also used in commercial business such as indoor tanning or as sanitation products. There are three different classifications of UV radiation: UVA, UVB, and UVC. UVC is the most harmful to people, but the effects are blocked by our planet's atmospheric O-zone layer. UVA is the least harmful, but penetrates the O-zone layer in large quantities. UVB is the subtype that causes most sunburn to people.

How Does UV Effect Skin?

Although UV light is necessary for humans to live healthy lives, its is also very harmful to humans if the amount of UV radiation a person is exposed to is not regulated. UV is beneficial because it promotes Vitamin D production in humans, but is most notably known for causing skin cancer in people that are predisposed to cancer. UV causes cancer because it penetrates skin cells, and alters their normal function which causes uncontrolled growth to occur. Since these cells are in an atypical mode, they also release release chemicals into the body that adversely effect neighboring skin cells.

How Does Sunscreen Protect the Skin?

Sunscreen has the ability to deflect UV rays away from the body, and prevents absorption of UV rays into skin cells. This decreases the chance of skin cells to develop into cancerous cells.

Eletromagnetic Spectrum


  1. MedlinePLUS: Drugs and Supplements [Internet]. 2007. Bethesda (MD): National Library of Medicine (US) and National Institutes of Health (US); [last updated 2007 Jan 31; cited 2007 Feb 20]. Available from: http://www.nlm.nih.gov/medlineplus/druginformation.html
  2. United States Environmental Agency [Internet]. 2010.[place unknown]: Office of Air and Radiation; [last updated 2010 July 1; cited 2012 March 19.] Available from: http://www.epa.gov/sunwise/doc/uvradiation.html

UV4U - Loyola University Maryland