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Impact assessment of building materials is a focused topic in the field of radioecology. A radiological survey has conducted to monitor radioactivity of most common building materials in Semnan Province, Iran, and assess the radiation risk. Activity concentrations of 226 Ra, 232 Th, and 40 K were measured in 29 samples including nine commonly used building materials that were collected from local suppliers and manufacturers, using a high purity germanium gamma-ray detector. The activity concentrations of 226 Ra, 232 Th, and 40 K varied from 6.7±1 to 43.6±9, 5.9±1 to 60±11, and 28.5±3 to 1085±113 Bq kg −1 with averages of 26.8±5, 22.7±4, and 322.4±4 Bq kg −1 , respectively. By applying multivariate statistical approach (Pearson correlation, cluster, and principal component analyses (PCA)), the radiological health hazard parameters were analyzed to obtain similarities and correlations between the various samples. The Pearson correlation showed that the 226 Ra distribution in the samples is controlled by changing the 232 Th concentration. The variance of 95.58% obtained from PCA resulted that the main radiological health hazard parameters exist due to the concentration of 226 Ra and 232 Th. The resulting dendrogram of cluster analysis also shows a well coincidence with the correlation analysis.

Based on the European Union Basic Safety Standards to protect people against exposure to ionizing radiation, establishing and addressing the reference levels for indoor radon concentrations is necessary. Therefore, the indoor radon concentration should be monitored and control in dwelling and workplaces. However, proper ventilation and sustainability are the major factors that influence how healthy the environment in a building is for its occupants. In this paper, the indoor radon distribution in a typical naturally ventilated room under two scenarios (when the door is closed and open) using the computational fluid dynamics (CFD) technique was studied. The CFD code ANSYS Fluent 2020 R1 based on the finite volume method was employed before the simulation results were compared with analytical calculations as well as passive and active measurements. The average radon concentration from the CFD simulation was found to be between 70.21 and 66.25 Bq m −3 under closed and open-door conditions, respectively, at the desired ventilation rate of 1 ACH (Air Changes per Hour). Moreover, the highest concentrations of radon were measured close to the floor and the lowest values were recorded near to the inlet, resulting in the airflow velocity profile. The simulation results were in good agreement with the maxima of 19% and 7% compared to analytical calculations at different indoor air velocities in the open- and closed-door scenarios, respectively. The measured radon concentrations obtained by the active measurements also fitted well with the CFD results, for example, with a relative standard deviation of around 7% and 2% when measured by AlphaGUARD and RAD7 monitors at a height of 1.0 m above the ground in the open-door scenario. From the simulation results, the effective dose received by an individual from the indoor air of the workplace was also calculated.

Recently, interest in measuring the concentration of 220 Rn in air has increased greatly following the development of standards and the calibration of monitoring instruments. In this study, a 220 Rn calibration chamber was designed and developed at the Institute of Radiochemistry and Radioecology (RRI) based on the computational fluid dynamics (CFD) method implemented in ANSYS Fluent 2020 R1 code at the University of Pannonia in Hungary. The behavior of 220 Rn and its spatial distribution inside the 220 Rn calibration chamber at RRI were investigated at different flow rates. The 220 Rn concentration was close to homogeneous under higher flow regimes due to thorough mixing of the gas inside the chamber. Predictions based on CFD simulations were compared with experimentally measured transmission factors (C out /C in ). The spatial distribution of 220 Rn was dependent on the flow rate and the positions of the inlet and outlet. Our results clearly demonstrate the suitability of the 220 Rn calibration chamber at RRI for calibrating monitoring instruments. Furthermore, the CFD-based predictions were in good agreement with the results obtained at higher flow rates using experimental and analytical models according to the relative deviation, with a maximum of approximately 9%.

A comprehensive study was carried out to measure indoor radon/thoron concentrations in 78 dwellings and soil-gas radon in the city of Mashhad, Iran during two seasons, using two common radon monitoring devices (NRPB and RADUET). In the winter, indoor radon concentrations measured between 75 ± 11 to 376 ± 24 Bq·m−3 (mean: 150 ± 19 Bq m−3), whereas indoor thoron concentrations ranged from below the Lower Limit of Detection (LLD) to 166 ± 10 Bq·m−3 (mean: 66 ± 8 Bq m−3), while radon and thoron concentrations in summer fell between 50 ± 11 and 305 ± 24 Bq·m−3 (mean 115 ± 18 Bq m−3) and from below the LLD to 122 ± 10 Bq m−3 (mean 48 ± 6 Bq·m−3), respectively. The annual average effective dose was estimated to be 3.7 ± 0.5 mSv yr−1. The soil-gas radon concentrations fell within the range from 1.07 ± 0.28 to 8.02 ± 0.65 kBq·m−3 (mean 3.07 ± 1.09 kBq·m−3). Finally, indoor radon maps were generated by ArcGIS software over a grid of 1 × 1 km2 using three different interpolation techniques. In grid cells where no data was observed, the arithmetic mean was used to predict a mean indoor radon concentration. Accordingly, inverse distance weighting (IDW) was proven to be more suitable for predicting mean indoor radon concentrations due to the lower mean absolute error (MAE) and root mean square error (RMSE). Meanwhile, the radiation health risk due to the residential exposure to radon and indoor gamma radiation exposure was also assessed.

A comprehensive radiological survey was carried out in an open-cut slate stone quarry. The activity of 226Ra, 228Ra and 40 K in the ore samples were measured as 38 ± 5, 41 ± 6 and 869 ± 52 Bq kg1, respectively. Outdoor radon and indoor radon concentrations were measured from 37 ± 7 to 193 ± 11 Bq m−3 (77 ± 8 Bq m−3), and 49 ± 6 to 253 ± 23 Bq m−3 (131 ± 13 Bq m−3), respectively. The average indoor and outdoor gamma dose were measured as 116 and 84 nSv h− 1, respectively. The annual effective doses were estimated between 1.0 ± 0.1 and 3.3 ± 0.3 mSv year−1. The annual lung cancer risks were calculated in the range of 3.3 × 10−2 to 13.12 × 10−2 % (7.72 × 10−2%).

The presence of radionuclides in environmental media, including sediment, is critical in assessing potential health risks due to external gamma radiation. This study investigates the spatial distribution of natural (Ra-226, Th-232, K-40) and artificial (Cs-137) radionuclides in sediment along the Dixcove coastline, Ghana, using High-Purity Germanium (HPGe) gamma-ray spectroscopy. The activity concentrations of Ra-226 ranged from ~14 to ~23 Bq/kg, Th-232 from ~3 to ~10 Bq/kg, and K-40 from ~44 to ~93 Bq/kg, with Cs-137 levels between 0.2 and 1.3 Bq/kg. The highest concentrations of Ra-226 and K-40 were found On-shore, suggesting terrestrial influence, while Th-232 displayed a more uniform distribution. Radiological risk assessments, including radium equivalent activity (Raeq), annual effective dose (AED), and gamma index (Iγ), confirmed that all measured values were below international safety thresholds, indicating no significant health risk. However, the variability in Cs-137 distribution suggests the need for continued monitoring to assess potential long-term contamination trends. A significant discrepancy was observed when comparing Cs-137 values from this study (maximum 1.3 Bq/kg) with previously reported data (~110 Bq/kg), raising concerns about methodological differences or environmental changes, which require further investigation. To address the observed discrepancies between this study and previous investigations, future research should incorporate in situ measurement techniques for a more comprehensive assessment of Cs-137 distribution.

In this work, the indoor radon concentration and radiation dose risks were studied in dwellings within the Greater Accra region, using CR-39 detectors. The indoor radon concentrations ranged from 36.1 ± 2.7 to 92.0 ± 5.2 Bq m − 3 with an annual average of 50.8 ± 3.4 Bq m − 3 . The annual mean effective dose was estimated as 1.3 mSv year −1 . Excess lifetime cancer risk and lung cancer cases were assessed with 5% annual lung cancer deaths due to radon was realized. Indoor radon maps created with ArcGIS software over a 5 × 5 km 2 grid showed radon prone areas in the region.