What is the WHO Radon Action Level for indoor radon concentration?

• A. 200 Bq/m3
• B. 150 Bq/m3
• C. 100 Bq/m3
• D. 250 Bq/m3

Answer: (C)

The World Health Organization (WHO) has established a guideline for indoor radon concentrations, recommending an action level of 100 Bq/m³. This level is based on the increased risk of lung cancer associated with prolonged exposure to radon, a naturally occurring radioactive gas that can accumulate in homes, particularly in areas with poor ventilation or high natural radon levels in soil and rock.

When indoor radon levels exceed 100 Bq/m³, the WHO advises taking action to reduce these levels to protect occupants' health. This may include improvements in ventilation, sealing of cracks and openings in the building's foundation, or more extensive mitigation systems. The emphasis on the 100 Bq/m³ threshold highlights the importance of proactive measures to minimize health risks associated with radon exposure.