What is the International Action Level for radon concentration?

The International Action Level for radon concentration is set at 200 Bq/m^3, which is the correct answer. This threshold is based on various health studies and is recognized by organizations such as the World Health Organization (WHO). When radon levels in homes or buildings reach this level, it signifies an increased risk for lung cancer due to radon exposure, prompting the need for mitigation actions.

Understanding this value is essential, as it serves as a guideline for public health and safety. It helps to inform homeowners about when radon mitigation measures should be taken to reduce the health risks associated with elevated radon levels. By recognizing this standard, mitigation specialists can effectively advise clients on necessary actions when radon levels exceed this international safety benchmark.