Dataset Direct Download Service (WFS): Know the radon potential of my commune on the department of the sarth.

Radon is a radioactive gas produced by the natural decay of uranium present in rocks. Pulmonary carcinogen, it can pose a health risk when it accumulates in buildings. Knowledge of the characteristics of geological formations in the territory makes it possible to identify areas where radon at high concentrations in buildings is most likely. This work, carried out by the IRSN at the request of the Nuclear Safety Authority, has made it possible to map the radon potential covering the entire metropolitan area. This mapping extracted from the national mapping leads to classifying the municipalities into 3 categories: Category 1 Category 1 radon-potential municipalities are those located on geological formations with the lowest uranium content. These formations correspond in particular to the limestone, sandy and clay formations of the large sedimentary basins (Paris Basin, Aquitaine basin) and basaltic volcanic formations (central Massif, French Polynesia, West Indies, etc.). On these formations, the vast majority of buildings have low radon concentrations. The results of the national measurement campaign in metropolitan France show that only 20 % of buildings exceed 100 Bq.m-3 and less than 2 % exceed 400 Bq.m-3. Category 2 Category 2 radon-potential municipalities are those located on geological formations with low uranium content but where particular geological factors may facilitate the transfer of radon to buildings. The municipalities concerned are particularly those intersected by major faults or where underground mining works are located in the basement... These particular geological conditions can locally facilitate the transport of radon from the rock to the soil surface and thus increase the likelihood of high concentrations in buildings. Category 3 Category 3 radon-potential municipalities are those with at least part of their area with geological formations with an estimated higher uranium content compared to other formations. The formations concerned include granitic massifs (Armoric Massif, Central Massif, French Guiana, etc.), certain volcanic formations (Central Massif, French Polynesia, Mayotte...) but also some black sands and shale. Of these uranium-rich formations, the proportion of buildings with high radon concentrations is higher than in the rest of the territory. The results of the national measurement campaign in metropolitan France show that more than 40 % of the buildings on these grounds exceed 100 Bq.m-3 and more than 6 % exceed 400 Bq.m-3. Note: in the case of municipalities with a large area — as is the case in particular for some overseas regions — the formations concerned sometimes occupy only a limited proportion of the municipal territory. In this case, mapping by commune does not represent the actual surface of a territory affected by radon potential but, in some way, the likelihood that there will be a source of exposure to high radon in the territory of a commune, even very localised. In order to visualise different areas within the municipal territory and to better appreciate the real radon potential in this area, reference should be made to the mapping shown according to the contours of the geological formations. For more information: www.irsn.fr/carte-radon