Ultraviolet (UV) Radiation

Ultraviolet (UV) radiation comes from the sun and artificial sources (e.g., indoor tanning equipment, welding equipment and lasers). Ultraviolet rays have wavelengths shorter than visible rays, so they are not in the visible light spectrum. This means we cannot see or feel them.


Types of Ultraviolet Radiation

  • UVA (longest wavelength): can penetrate the middle layer of the skin (dermis).
  • UVB (shorter wavelength): can penetrate the outer layer of the skin (epidermis).
  • UVC (shortest wavelength): blocked by the stratospheric ozone layer.

Everyone is exposed to UV radiation from the sun. An increasing number of people are exposed to artificial sources such as tanning beds. Ultraviolet radiation is a major factor in the development of skin cancer, along with other diseases. To find out how UV radiation affects us, see Health Impacts of Exposure to Ultraviolet (UV) Radiation.