Radiation is energy that travels in the form of waves or particles and is part of our everyday environment. People are exposed to radiation from cosmic rays, as well as to radioactive materials found in the soil, water, food, air and also inside the body.
Radiation is the emission of energy as electromagnetic waves or moving subatomic particles. Natural radiation comes from many naturally occurring radioactive materials found in soil, water, air and in the body. Every day, people inhale and ingest forms of radiation from air, food and water.
WHO fact sheet on ionizing radiation, health effects and protective measures: includes key facts, definition, sources, type of exposure, health effects, nuclear emergencies, WHO response.
We work to strengthen radiation protection of the public, patients and workers worldwide. We provide Member States with evidence-based guidance, tools and technical advice on public health issues related to ionizing and non-ionizing radiation.
The conference on radiation protection in medicine marks a milestone in assessing progress since the Bonn Call for Action, launched in 2012 to strengthen global radiation protection in medicine. Over the past decade, international and scientific organizations, regulators and professional societies have worked to implement its ten priority actions.
Ultraviolet (UV) radiation covers the wavelength range of 100–400 nm, which is a higher frequency and lower wavelength than visible light. UV radiation comes naturally from the sun, but it can also be created by artificial sources used in industry, commerce and recreation.
Radiation exposure Ionizing radiation exposure is measured as "absorbed dose" in gray (Gy). The "effective dose" measured in sievert (Sv) takes account of the amount of ionizing radiation energy absorbed, the type of radiation and the susceptibility of various organs and tissues to radiation damage.