Ultraviolet radiation (UV)

UV Index

What is the UV Index (UVI)?

  • The UVI is a measure of the level of UV radiation.
  • The values of the index range from zero upward - the higher the UVI, the greater the potential for damage to the skin and eye, and the less time it takes for harm to occur.
  • The UVI is an important vehicle to alert people about the need to use sun protection.

A marked increase in the incidence of skin cancer in fair-skinned populations worldwide is strongly associated with excessive UV radiation exposure from the sun and possibly artificial sources such as sunbeds. Current evidence indicates that personal habits in relation to sun exposure constitute the most important individual risk factor for UV radiation damage.

The UV Index is an important vehicle to raise public awareness of the risks of excessive exposure to UV radiation, and to alert people about the need to adopt protective measures. As part of an international effort, the UV index was developed by WHO, the United Nations Environment Programme, and the World Meteorological Organization. Encouraging people to reduce their sun exposure can decrease harmful health effects and significantly reduce health care costs.

The INTERSUN programme promotes the harmonized use of the UVI, and advises governments to employ this educational tool in their health promotion programmes. WHO encourages dissemination channels such as the media and tourism industry to publish the UVI forecast and promote sun protection messages.

UV international colour codes