What must be avoided to ensure the filter in RDP measurement devices remains effective?

To ensure the filter in Radon Detection Protocol (RDP) measurement devices remains effective, it is crucial to avoid contact with non-RDP particles. The primary function of the filter in these devices is to selectively capture radon progeny while minimizing interference from other particulate matter that may be present in the environment. Non-RDP particles can introduce additional noise or inaccuracies in the measurements, leading to potentially misleading results. By keeping the filter free from these particles, the integrity of the data collected is maintained, allowing for a more precise assessment of radon levels.

While other factors, such as humidity, temperature, and light exposure, may also affect the performance and accuracy of measurement devices, the specific concern with non-RDP particles directly impacts the filter's ability to provide a clear and detectable signal relevant to radon measurement.