Radon testing should not be performed in which of the following areas?

Radon testing is typically performed in areas where people spend a significant amount of time, and one of the critical guidelines is to focus on the lowest level of the home that is utilized frequently, such as living rooms and bedrooms. Testing in bathrooms is usually not recommended because they are often not used as living spaces over extended periods. Also, bathrooms may have different ventilation dynamics compared to more commonly occupied spaces, which can lead to less reliable radon measurements. The goal of radon testing is to assess long-term exposure risks, so indoor living spaces that are used regularly provide a more accurate representation of radon levels affecting occupants.

On the other hand, areas like living rooms, basements, and attics may be appropriate for testing depending on their use and structural characteristics, though basements are often the primary focus due to the tendency for radon accumulation at lower levels of the house. Hence, stating that radon testing should not be performed in bathrooms aligns with best practices in assessing radon exposure.