Radon - Physical, metrological and health aspects

According to the World Health Organization (WHO), radon is the second leading cause of lung cancer after smoking. For the French population, exposure to radon is the primary source of exposure to ionizing radiation of natural origin. Since 1987, radon has been classified as a definite human lung carcinogen (Group I) by the WHO's International Agency for Research on Cancer (IARC).

In outdoor air, radon is rapidly diluted and its average concentration is generally very low. In enclosed spaces such as buildings, particularly basements and first floors, it can accumulate to sometimes very high concentrations.

The quantitative health impact assessment, updated in 2018 on the most recent databases, confirmed the data published in 2007: around 4,000 new cases of lung cancer per year and 3,000 lung cancer deaths per year would be attributable to radon in indoor air in France.

Radon is a public health problem because exposure to it affects the whole population, mainly in the home, and more particularly workers in the workplace.

The entry into force of Decree no. 2018-437 of June 4, 2018 on the protection of workers against the risks arising from ionizing radiation, transposing Directive 2013/59/Euratom, sets the basic standards for health protection against the dangers arising from exposure to ionizing radiation. Indeed, radon risk has been inserted into the general occupational risk prevention approach, resulting in a graduated approach to occupational risk assessment for radon risk.

In its WHO Housing and health guidelines, the WHO also recommends considering radon in the overall context of indoor air quality. The health risk needs to be better understood by the population, whose perception of it needs to be reinforced, which will lead to the radon issue gaining in importance.