In radon measurement, what is considered the best practice after implementing a mitigation system?

The best practice after implementing a mitigation system for radon is to conduct re-testing 24 hours post-installation. This timing allows for an accurate assessment of the effectiveness of the mitigation system. Radon levels can fluctuate, so waiting for an extended period, such as a month, may not provide immediate feedback on whether the mitigation efforts have successfully reduced radon levels to acceptable thresholds.

Testing shortly after installation helps confirm that the system is functioning as intended and that radon levels are below the action level. If significant levels of radon are still detected shortly after the installation, it may indicate a need for adjustments to the mitigation system. On the other hand, testing immediately after installation is important, as it typically provides a reliable indication of radon levels at a time when the system is first put into operation.

Waiting for a weather change is not considered a best practice because factors such as temperature and barometric pressure can influence radon levels, potentially skewing results if testing is delayed without cause. Since radon levels can vary significantly with weather conditions, performing tests under stable conditions soon after installation is essential for obtaining a valid measure of the mitigation system's performance. Therefore, the timing of re-testing is crucial in ensuring that the radon mitigation system is