This Tuesday, December 3, at 6:30 p.m., the Chamborigaud multipurpose room is hosting a public meeting on radon gas and its dangers. As in other regions where granite is present, radon presents a health danger in the Cévennes when it accumulates in homes. Individuals in municipalities placed at level 3 of vigilance will be able to receive radioactivity measurement kits at their home, as well as measures to avoid concentration.
The famous granites of Mont Lozère, from which radon comes in particular • François Desmeures
Since 2017, it has been the subject of regular campaigns in the Cévennes and, since 2018, it has been one of the mandatory diagnostics to be provided in the event of the sale of a house. A natural phenomenon, which can prove to be a public health problem, radon gas is linked to the presence of granite rock, even if shale is also concerned, but more at the margins. It is therefore no coincidence that the meeting takes place in Chamborigaud, a stone's throw from the granites of Mont Lozère. But, apart from Piedmont, which is rather limestone, all of the Cévennes are affected by the phenomenon.
View to the north of the Col de l’Asclier • François Desmeures
“An IRSN card (institute of radiation protection and nuclear safety, *) classifies the municipalities according to zones 1 to 3, knowing that zone 3 is the one where the most radon has been recordedexplains Laurianne Héran, who works at the CPIE (permanent center for environmental initiatives) in Gard, responsible for providing information on the dangers of radioactive gas. However, we do not know the housing-by-housing data.” The card therefore allows “a first piece of information for people is to regularly ventilate their rooms”. Winter included, gas tends to accumulate in a confined house.
The southern slope of Mont Lozère, above the hamlet of Finiels • François Desmeures
The information campaign is supported by the Regional Health Agency (ARS). “We can distribute kits for people who live in zone 3”continues Laurianne Héran. An area which concerns the entire Cévennes chain, therefore, almost the entire north of the department, from Courry in the east, to Lanuéjols in the west, while Alzon, Arrigas, Sumène, Monoblet or Alès form the southern limit.
“Radon gas is found in the soil, it comes out through cracks, explains Laurianne Héran. The danger is when he enters buildings and can't get out. It is mainly found in very confined housing, in cellars, crawl spaces and housing close to the ground.” Colorless, odorless, it affects the lungs and has been classified as carcinogenic by the World Health Organization (WHO). “It can also enter through sockets, electrical conduits.” Canadian wells, which run pipes under the house to regulate the temperature, should therefore be avoided in a concerned area.
Aigoual, just as concerned by the presence of granite, therefore radon • François Desmeures
In an affected area, sometimes small jobs are enough to preserve your home. Like improving the waterproofing of the floor, for example. But some work is much heavier and can only benefit from aid in the context of energy renovation. “On new housing, there are now minimum waterproofing standards to respect”reassures Laurianne Héran. Finally, there are now special radon ventilation systems (VMI: mechanical insufflation ventilation), which can be installed during renovations.
South view of the Col de l’Asclier • François Desmeures
Until the end of February, on request, the CPIE du Gard can therefore provide measurement kits for individuals to assess the gas concentration in their homes. “The dosimeter makes it possible to measure over a long period. The devices are then sent back to the ARS which calls on an independent laboratory to measure the becquerels per cubic meter. Above 300, there is a danger to health. And above 600, work must be planned immediately.” Without panicking the residents, the CPIE du Gard species, this afternoon in Chamborigaud, alerted the residents to a very real health risk, but which can easily fade away if it is properly identified.
