• English
  • العربية
  • 中文
  • Français
  • Русский
  • Español


Radon is a radioactive gas that has no colour, smell or taste. It is produced in the ground from uranium and diffuses into the atmosphere. High concentrations of radon may build up in enclosed spaces such as buildings and long-term exposure can increase the risk of lung cancer.

Homes with high radon concentrations are often located in areas of a particular geology, such as granites or shales, which often contain a high amount of uranium. Radon can also be found in groundwater supplies and can be released into the indoor air when taps and showers are turned on. The only way to know if a home has a high concentration of radon is to have it measured. Commercial radon measurement services are available in many countries.                         

For most people, radon is the largest source of radiation exposure throughout their lifetime. Radon is the second most important cause of lung cancer after smoking and the leading cause of cancer among non-smokers. The link between exposure to radon and lung cancer is scientifically proven and even the moderate concentrations found in many homes present an increased risk.

High levels of radon in a house can be reduced by various corrective actions, which are well developed and proven to work. Attention should be paid to the thermal retrofitting of existing buildings as low ventilation rates decrease the overall quality of indoor air and can increase radon levels. Preventing radon accumulation in newly built houses is now included in many national building codes. This approach is normally cheaper than corrective actions and is often highly cost-effective compared with other public health interventions.

The 2014 edition of the International Basic Safety Standards requires that national authorities provide general information on radon, including information on health risks and the synergy with smoking. Where there is a need to do so, a national radon action plan should be developed and implemented to reduce the public health risk from radon.

The IAEA has published a safety guide on Protection of the Public against Exposure Indoors due to Radon and Other Natural Sources of Radiation to assist national authorities in reducing exposure to radon. This safety guide also includes guidance on how to prepare a radon action plan.

Stay in touch