The Autorité de sûreté nucléaire (ASN) publishes the 2020-2024 radon risk national action plan (PAR 4). Building on the National Health-Environment Plan 4 (PNSE), “My environment, my health” (2020-2024), this fourth edition is the fruit of collaboration between ASN, the Ministries for Health, Ecology, Construction and Labour, national experts , regional actors , radon measurement professionals and associations active in this area.
Radon is a naturally occurring radioactive gas, recognised as being carcinogenic, and is present everywhere on the surface of the Earth. In France, radon is the second cause of lung cancer (about 3,000 fatalities per year), behind smoking. Joint exposure to radon and tobacco substantially increases the risk of developing lung cancer.
In the outside air, radon is rapidly diluted and its average concentration usually remains very low. In enclosed spaces, it can build up and sometimes reach high concentrations, which then represent a health risk.
Granite soils give off more radon than sedimentary soils, owing to the higher concentrations of uranium that they naturally contain. Municipalities in France are divided into 3 types of radon potential zones, based on geological criteria.
Information and prevention are thus essential in managing this risk, so that exposure can be reduced or kept as low as reasonably achievable, given the current state of technical knowledge and economic and societal factors. This underpinned the production of the PAR 4, taking account of all the exposure locations (home, workplace and facilities open to the public) and all those potentially exposed (population and workers).
Since 2005, successive action plans have helped improve our understanding of radon and prevention nationwide, while contributing to regulatory changes on this subject. The radon concentration in buildings can be easily measured with a detector that is installed for a period of two months in the home, areas open to the public or the workplace. If concentration is moderate, simple measures (ventilation, sealing) are sufficient to reduce exposure. If the concentration is higher, a building professional must be called in. In any case, ventilation of the premises for at least 10 minutes per day is considered to be good practice, both in winter and in summer.
This plan follows through on the momentum developed under the PAR 3, for which ASN also publishes the results. These results show significant regulatory changes. Since 2016, radon has been considered to be an indoor air pollutant and management of this risk is part of a broader policy to improve indoor air quality. In addition, an obligation to inform buyers and tenants of the radon risk was introduced in those municipalities with a significant radon potential in 2018.
Although virtually all of the PAR 3 actions have been completed, the efforts made must be continued:
- the actors governed by the new regulatory provisions must be informed and assisted with their implementation
- public awareness of the radon risk needs to be improved
- improved understanding of the exposure of the population must be sought
- evaluation of the effectiveness of preventive measures in new constructions and corrective measures in existing constructions must be continued.
A system of specific indicators will enable the effectiveness of the national strategy implemented under the national action plan to be evaluated as of 2021.
To find out more
 French Institute for Radiation Protection and Nuclear Safety and the Building Industry Scientific and Technical Centre.
 Regional Health Agencies – ARS ; Study and assessment centres for risks, the environment, mobility and development – Cerema ; Regional Directorates for Companies, Competition, Consumer affairs, Labour and Employment - DIRECCTE.
Date of last update : 07/11/2022