Temporal uncertainty in rational method: Reassessment of data from the article “Short-term temporal variability of radon in Finnish dwellings and the use of temporal correction factors”

<ns3:p>Background This in-depth study is based on the materials presented in the article referenced in the title. The study in Finnish dwellings provides valuable initial experimental data in the form of year-long continuous measurements of radon concentrations across a large number of buildings. However, the data analysis relied on a traditional (outdated and inefficient) approach focusing on the Temporal Correction Factor that raises significant questions regarding the robustness of conclusions and the strength of the underlying assumptions. Methods A reassessment of the initial experimental data was performed based on previously published rigorous mathematical algorithms of the Rational Method within the fundamental metrology concepts such as “measurement uncertainty” and “conformity assessment”. The uniqueness of this method lies in the fact that it takes into account both temporal (key) and instrumental uncertainties in the conformity assessment of a room (or the entire building) to safety requirements. Results (1) Refinement of limitations for the Rational Method, including guidelines for statistical data collection to enhance the representativeness of indoor radon temporal uncertainty estimates. This is particularly relevant given the issue of relatively low radon concentrations over weeks and months, even in buildings with high annual averages. (2) Clarification of temporal uncertainty values based on the initial experimental data, supporting the justification of previously published uncertainty estimates as potentially universal across countries in the absence of reliable country-specific data. (3) Critical evaluation of the traditional research design and approach to indoor radon testing in Finland, including the statement that short-term radon measurements are not yet recommended. Conclusions The results of our previous and current studies demonstrate that short-term radon measurements form the foundation of Rational Method for indoor radon testing, which, for the first time, has full metrological support because it takes into account the main components of uncertainty in decision-making.</ns3:p>