Radon is a naturally occurring radioactive gas, colorless and odorless, resulting from the decay of uranium present in soil and rocks. It can infiltrate buildings and poses a major public health risk. This article explores the risks associated with radon as well as the current regulations aimed at limiting its impact.
Radon risks
Prolonged exposure to radon is the second leading cause of lung cancer after smoking. When inhaled, it emits alpha particles that can damage lung cells and promote tumor development. The risk increases significantly for smokers, as the effects of tobacco and radon reinforce each other.
Certain geographical areas are more exposed than others due to the nature of the subsoil. Poorly ventilated buildings and inadequately insulated basements are particularly vulnerable to radon accumulation.
Mechanisms of Radon infiltration
Radon infiltrates buildings mainly through cracks in foundations, construction joints, pipelines, and crawl spaces. This process is exacerbated by the chimney effect, where rising warm air creates a pressure difference that draws radon-rich air from the ground. Some building materials, such as granite or certain natural stones, can also be sources of radon. Good building design can thus play an important role in limiting exposure.
Radon regulations
Due to the dangers of radon, several countries have implemented strict regulations. The European Union, for example, adopted Directive 2013/59/Euratom, which sets standards for radiation protection.
In France, regulations are defined by the Public Health Code and the Labor Code. The main measures include:
- Reference threshold: Set at 300 Bq/m3 for workplaces and certain public buildings.
- Measurement obligation: In high-radon potential areas, employers and public building owners must monitor radon levels.
- Corrective actions: If the threshold is exceeded, measures must be taken to reduce exposure, such as improving ventilation and sealing floors.
- Public awareness: Information campaigns are conducted to encourage individuals to measure radon levels in their homes and adopt corrective solutions.
Comparison of International standards
While France follows the recommendations of the European Union, other countries have different approaches. In the United States, the Environmental Protection Agency (EPA) recommends an action level of 148 Bq/m3. Canada has set its threshold at 200 Bq/m3. In Switzerland, where some regions are particularly exposed, strict measures are imposed in the construction of new buildings to limit radon infiltration.
Radon detection and reduction technologies
Radon detection can be carried out using passive dosimeters (activated charcoal, alpha track detectors) or active sensors that continuously measure radon concentrations. To reduce radon levels, several technical solutions exist:
- Controlled mechanical ventilation (CMV): Renews indoor air and lowers radon concentration.
- Sub-slab depressurization system: Creates suction beneath the foundations to prevent radon entry.
- Sealed barriers: Installation of airtight membranes under slabs to block radon seepage.
Case studies and concrete examples
Some French regions, such as Brittany and the Massif Central, have already implemented specific action plans. In Finland, where radon levels are high, government subsidies help individuals finance mitigation work. Schools and hospitals have been renovated to reduce radon exposure, illustrating the importance of corrective measures.
Environmental impact and other associated risks
Beyond residential buildings, radon can also contaminate groundwater. In some mining regions, miners are exposed to very high concentrations, increasing their risk of lung cancer. The management of radioactive waste and radon's impact in the extractive industry are significant environmental concerns.
How to protect yourself from Radon?
To reduce radon exposure, several solutions exist:
- Improve ventilation: Regularly ventilate buildings to renew air and expel radon.
- Ventilate basements: Install mechanical ventilation systems to prevent gas accumulation.
- Enhance sealing: Seal cracks in walls and floors to limit radon infiltration.
- Regular measurement: Use dosimeters to monitor radon concentrations in homes and workplaces.
Radon represents a major public health issue, and its management relies on strict regulations and effective preventive measures. Monitoring and reducing radon concentrations in buildings are essential to mitigating health risks.