What is the WHO reference action level for radon?

The World Health Organization (WHO) has established an action level for radon exposure, which is crucial for health and safety guidelines. That action level is set at 100 Bq/m^3. This threshold is intended to prompt action in terms of radon mitigation when indoor radon levels reach or exceed this value. The 100 Bq/m^3 level is based on various studies indicating that exposure to higher levels of radon significantly increases the risk of lung cancer.

The decision for this specific action level is influenced by a combination of epidemiological studies that demonstrate the relationship between radon exposure and health risks, as well as advocating for preventive measures to protect public health. When measured radon levels in a dwelling or building reach 100 Bq/m^3, it is recommended to take action such as improving ventilation, sealing cracks, and possibly employing radon mitigation systems to reduce indoor radon concentrations.