What percentage is typically used as a threshold for radon mitigation recommendations from testing?

The threshold of 4 picocuries per liter (pCi/L) is widely recognized as the action level for radon mitigation recommendations. This benchmark is established based on health risk assessments conducted by various health organizations, including the Environmental Protection Agency (EPA). When radon concentrations in indoor air reach or exceed this level, it indicates a significant increase in the potential risk of lung cancer, particularly with long-term exposure.

Mitigation efforts are advised at this level to reduce radon concentrations to safer levels, thus protecting occupants from the health risks associated with prolonged radon exposure. This threshold is part of established guidelines, aiming to promote public health awareness and safety in environments where radon exposure is a concern.