Radon, a gas that must be wary?

It is not, it does not smell, and yet, radon is everywhere. The second national plan intended to reduce the risk associated with radon is private homes. This radioactive gas is sometimes dangerous. So, should we be afraid? Radon is a naturally occurring gas in the ground. It is issued by the decay of radium, […]

It is not, it does not smell, and yet, radon is everywhere. The second national plan intended to reduce the risk associated with radon is private homes. This radioactive gas is sometimes dangerous. So, should we be afraid?

Radon is a naturally occurring gas in the ground. It is issued by the decay of radium, himself present in the Earth’s crust. But volatile, radon escapes from the mineral matrix in his ‘father’ radium…

This natural radiation poses no problem outdoors, since radon is diluted in the atmosphere. On the other hand, it can accumulate in enclosed and confined as housing and offices spaces. Or we spend approximately 90% of our time in buildings.

Where is radon? Thirty-one departments are particularly exposed to radon. “The presence of radium, and thus radon, is most important in the ancient massifs that are granite, volcanic and mountainous massifs as well as in some sedimentary terrain”, explains Alain Rannou, specialist radon the radiation protection and nuclear safety Institute…

The nature and the permeability of the ground also influence the diffusion of radon in the air. For example, he escaped easily porous and permeable soils such as sands and alluvium. And faults, the caves and the underground galleries (mines) promote its transfer over long distances, since no obstacle then slows its spread…

Is this gas dangerous? Radon is a proven cause of lung cancer, the second after smoking, the first among non-smokers. Smokers, however, remain the main victims, since they increase the risk…

In France, the InVS Institute estimates that 5 to 12% of lung cancer deaths are due to radon. “In reality, it is its degradation products that are dangerous. Radon has little affinity for biological tissues and it is exhaled almost as quickly as it is inhaled,”says Alain Rannou..

But his descendants are solid particles. Once inhaled, they are deposited in the respiratory tree. The energy they release damaged tissues, including the basal cells of the respiratory epithelium, particularly radiosensitive, which are very important because able to transform into any other type of bronchial cell…

Indoor air radon is also suspected to increase the risk of leukemia in childhood, but the national cancer Institute finds that it is not shown…

How radon enters homes? Inside, the radon can reach significant concentrations if the renewal of the air is low. Basements, basements, crawl spaces, in contact with the ground, typically contain the largest gas concentrations..

Radon can also seep into homes through cracks at the level of the floors and walls, joints between walls, passages, pipes, cables or water pipes. Otherwise, more soil is rich in radon and over the construction of the House is “porous”, most indoor air will be contaminated…

How to protect themselves?   The best solution is shaped custom according to the architecture of the accommodation, with or without basement, with or without floor, and after that identified radon entry points”, recommends Bénédicte Gross, specialist radon…

Protective measures are based on two principles: preventing the entry of radon in housing and facilitate the exit. Logic! This means the tightness of the housing building, the improvement of his ventilation and, if necessary, treatment of his basement…

“Parts to live in contact with the ground are most concerned”, observes the specialist. Different actions are possible: quench the slab and the walls of the House, sometimes even ceilings, sealing cracks, redo the seals, seal the passages around the ducts and pipes, by choosing waterproof materials to the passage of the gas…

Namely: adhesive silicone, sealants to permanent elasticity, glass, 1.5 mm thick PE – HD plastic, armed with 1 mm thick PVC and oil polymers are radon-tight, but bricks, Terra cotta and synthetic paints are not…

Once the parts are well isolated, need to ensure that the renewal of air is sufficient. Aeration can be natural, by opening windows, or improved, through the depression of the ground, the overpressure of the building layout or installation of mechanical ventilation. Installation costs vary from 300 to $5,000 according to the technique, but if in doubt, better to take the opinion of professionals as badly fitting DIY can be brought even more radon!.

How do I know if it is exposed? In places open to the public (schools, health facilities and spas) and workplaces of the 31 priority departments, rules exist since 2004: the State or the employer is under an obligation to measure radon levels of its premises by an approved body.

In private accommodation, can perform the measurements oneself with a dosimeter. Several companies (Algade, Dosirad, Saphymo) provide reliable detectors at a moderate cost (approx. $20). “As a photographic film is sensitive to light, these detectors are sensitive to alpha particles emitted by radon,” explains Alain Rannou. The measurement of the radioactivity is expressed in becquerels (Bq)..

A dose to less than 100 Bq/m3 air is considered acceptable for health. It is the threshold value that the World Health (who) Organization recommends not to exceed. Between 200 and 400 Bq/m3, “it is reasonable to bring in professionals to identify where are the points of entry of radon and correct”, advises Alain Rannou. The European Commission also provides a value of 200 Bq/m3 must not exceed for new construction. 1 000 Bq/m3, should take prompt measures of protection. This value would be an alert threshold. .

In France, the average rate of radon in dwellings is 90 Bq/m3 (but 11.3% exceed 200 Bq/m3). According to who, the risk of lung cancer increases by 16% per additional 100 Bq/m3 for household radon…

Learn more: the site of the Institute for radiological protection and nuclear safety on the national campaign of the radon measure.    .

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