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”

<b>Abstract</b>This in-depth study is based on the materials presented in the article referenced in the item title. The study in Finnish dwellings provides valuable initial experimental data in the form of year-long continuous measurement of radon concentrations across a large number of buildings. However, the data analysis relied on a traditional (outdated and inefficient) approach that raises significant questions regarding the robustness of conclusions and the strength of the underlying assumptions.A reassessment of the initial experimental data using rigorous mathematical algorithms of the Rational Method enabled the achievement of several important objectives:(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. However, 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, received metrological support.The original research article under the same title is available on the Open Research Europe platform (https://open-research-europe.ec.europa.eu/articles/5-328/v1).<b>Description of data collection and processing</b>A description of the collection (initial experimental) data in the form of year-long continuous measurements (YLCM) of indoor radon concentrations is given in the article: Turtiainen, T., Kojo, K., Kurttio, P. Short-Term Temporal Variability of Radon in Finnish Dwellings and the Use of Temporal Correction Factors. Atmosphere 2025, 16, 489 (https://www.mdpi.com/2073-4433/16/5/489). This experimental (original) data is published by experts from the Radiation and Nuclear Safety Authority (STUK, Finland) as Supplementary Materials with open access: https://www.mdpi.com/article/10.3390/atmos16050489/s1.The original STUK data was processed based on mathematical algorithms within the Rational Method, which are presented in detail in the articles: Tsapalov, A., Kovler, K. Metrology for Indoor Radon Measurements and Requirements for Different Types of Devices. Sensors 2024, 24, 504 (https://www.mdpi.com/1424-8220/24/2/504), and Tsapalov, A., Kovler, K., Kiselev, S., Yarmoshenko, I., Bobkier, R., Miklyaev, P. IAEA Safety Guides vs. Actual Challenges for Design and Conduct of Indoor Radon Surveys. Atmosphere 2025, 16, 253 (https://www.mdpi.com/2073-4433/16/3/253), and Tsapalov A. 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” [version 1; peer review: awaiting peer review]. Open Res Europe 2025, 5:328 (https://doi.org/10.12688/openreseurope.21469.1).The main objective of this data processing was to clarify the temporal uncertainty in indoor radon concentration based on the original data, which were obtained by other (independent) researchers from STUK.In addition, processing of the original STUK data included preliminary data selection by excluding those YLCMs that satisfied two conditions:1. YLCM is unsuitable for evaluating temporal uncertainty if (i) the duration of data registration gaps exceeds 10 consecutive days or 15 cumulative days within a year, (ii) the annual average radon concentration is less than 50 Bq/m³, and2. YLCM is unsuitable for evaluating temporal uncertainty if the ratios (annual average / daily average) of radon concentrations exceed a threshold value ХR for more than ХD days cumulatively over the year. Both parameters (XR = 6 and XD = 15 days) were determined using a special modeling algorithm included in the processing.<b>Description of the dataset archive structure</b>Excel file “Original STUK data”: The initial experimental data published by STUK experts.Excel file “Selected STUK data_Cond_1 and Figures”: Selected STUK data based on condition 1 with 38 figures for each of YLCM.Excel file “Selected STUK data_Cond_2”: Selected STUK data based on conditions 1 and 2 using a special modeling algorithm.Folder “Temporal uncertainty_partial values”: The archive of 38 Excel files containing a processing algorithm for determining the partial values of temporal uncertainty for each of the 38 YLCMsFolder “Temporal uncertainty_general values with exclusions”: The archive of 6 Excel files containing a processing algorithm for determining the general values of temporal uncertainty for all (38) YLCMs, as well as excluding some YLCMs in accordance with condition 2.