If both radon results are below 4 pCi/L, what is the next step?

When both radon results are below 4 pCi/L, calculating the RPD (Relative Percent Difference) and reporting the results is the most appropriate next step. The RPD is an important statistical measure used to assess the consistency and reliability of the two radon tests that have been conducted.

If the RPD is found to be within an acceptable range, it indicates that the results are consistent, which strengthens the conclusion that the radon levels are indeed below the action level, and reporting these results can provide reassurance to all parties involved. If, however, the RPD indicates potential variability or inconsistency between the tests, it may suggest the need for further investigation or testing to ensure accurate results.

Taking this step is crucial for ensuring that any radon exposure risks are properly assessed, especially if the property is to be sold or transferred. It also helps in documenting compliance with safety standards and can serve as a reference for future assessments or testing in the property.