Dependence of indoor radon concentrations (IRCs) in the ground floors of 1200 buildings across Montenegro on 11 factors was analyzed. A group of 734 buildings, for which none of the analyzed factors ...was missing, was further analyzed using the logistic regression method, in order to develop a prediction model for IRC occurrence above the national reference level for new buildings (200 Bq/m3). Applying the forward stepwise method, and based on likelihood ratios, five explanatory variables—municipality, type of building, presence of basement, window frames, and period of construction—were selected for including into the final logistic regression model for predicting probability of IRC > 200 Bq/m3. The final model explained 77.1% of the observed IRCs, while the obtained Area under the Curve of 0.8018 classified the model as having a very high predictive ability. Achieving similar values for both the final prediction model and the validation model, for sensitivity, specificity, and accuracy, confirmed the applicability of the developed model.
•Model for predicting indoor radon concentrations (IRCs) above 200 Bq/m3.•Model based on the logistic regression method.•Predictors: municipality, type of building, basement, windows, age of building.•Model explained 77.1% of the observed ground floor IRCs.•Excellent performance of the prediction model (AUC = 0.8018).
In many countries, assessment programmes are carried out to identify areas where people may be exposed to high radon levels. These programmes often involve detailed mapping, followed by spatial ...interpolation and extrapolation of the results based on the correlation of indoor radon values with other parameters (e.g., lithology, permeability and airborne total gamma radiation) to optimise the radon hazard maps at the municipal and/or regional scale. In the present work, Geographical Weighted Regression and geostatistics are used to estimate the Geogenic Radon Potential (GRP) of the Lazio Region, assuming that the radon risk only depends on the geological and environmental characteristics of the study area. A wide geodatabase has been organised including about 8000 samples of soil-gas radon, as well as other proxy variables, such as radium and uranium content of homogeneous geological units, rock permeability, and faults and topography often associated with radon production/migration in the shallow environment. All these data have been processed in a Geographic Information System (GIS) using geospatial analysis and geostatistics to produce base thematic maps in a 1000 m × 1000 m grid format. Global Ordinary Least Squared (OLS) regression and local Geographical Weighted Regression (GWR) have been applied and compared assuming that the relationships between radon activities and the environmental variables are not spatially stationary, but vary locally according to the GRP. The spatial regression model has been elaborated considering soil-gas radon concentrations as the response variable and developing proxy variables as predictors through the use of a training dataset. Then a validation procedure was used to predict soil-gas radon values using a test dataset. Finally, the predicted values were interpolated using the kriging algorithm to obtain the GRP map of the Lazio region. The map shows some high GRP areas corresponding to the volcanic terrains (central-northern sector of Lazio region) and to faulted and fractured carbonate rocks (central-southern and eastern sectors of the Lazio region). This typical local variability of autocorrelated phenomena can only be taken into account by using local methods for spatial data analysis. The constructed GRP map can be a useful tool to implement radon policies at both the national and local levels, providing critical data for land use and planning purposes.
•Geogenic Radon Potential (GRP) measures what Earth delivers in term of radon.•The estimation of the Geogenic Radon Potential map of the Lazio region is proposed.•Geological and geochemical data are used as proxies and response variables.•Geographically Weighted Regression and geostatistics are applied to construct GRP map.
Abstract
Radon inhalation decreases the level of lipid peroxide (LPO); this is attributed to the activation of antioxidative functions. This activation contributes to the beneficial effects of radon ...therapy, but there are no studies on the risks of radon therapy, such as DNA damage. We evaluated the effect of radon inhalation on DNA damage caused by oxidative stress and explored the underlying mechanisms. Mice were exposed to radon inhalation at concentrations of 2 or 20 kBq/m3 (for one, three, or 10 days). The 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels decreased in the brains of mice that inhaled 20 kBq/m3 radon for three days and in the kidneys of mice that inhaled 2 or 20 kBq/m3 radon for one, three or 10 days. The 8-OHdG levels in the small intestine decreased by approximately 20–40% (2 kBq/m3 for three days or 20 kBq/m3 for one, three or 10 days), but there were no significant differences in the 8-OHdG levels between mice that inhaled a sham treatment and those that inhaled radon. There was no significant change in the levels of 8-oxoguanine DNA glycosylase, which plays an important role in DNA repair. However, the level of Mn-superoxide dismutase (SOD) increased by 15–60% and 15–45% in the small intestine and kidney, respectively, following radon inhalation. These results suggest that Mn-SOD probably plays an important role in the inhibition of oxidative DNA damage.
The effective technique of RAD7 has been applied to determine the concentrations of radon and annual effective dose of mineral water samples collected from Iraqi local markets. The results show that ...the level of radon concentrations in mineral water samples ranged between 0.035 and 0.248 Bq/L with an average value of 0.120 Bq/L. In addition to the annual effective dose ranged from 0.129 to 0.905 uSv/y with an average value of 0.440 uSv/y. It was found that the mean value of radon concentration and annual effective dose in all the studied mineral water samples were within the acceptable limits according to the International Commission on Radiological Protection (ICRP) and World Health Organization (WHO).
This paper compares the results of measurements taken in the underground workings of active and tourist mines. In these facilities, the aerosol size distributions of ambient aerosols at key ...workplaces and the distributions of radioactive aerosols containing radon decay products were determined. Based on these studies, dose conversions used for dose assessment and unattached fractions were determined. In addition, radon activity concentrations and potential alpha energy concentrations of short-lived progeny were also measured in the mines to determine the equilibrium factor. The dose conversions varied between 2-7 mSv/(mJ × h × m
). The unattached fraction measured in active coal mines ranged from 0.01-0.23, in tourist mines from 0.09-0.44, and in the tourist cave it was 0.43. The results showed significant discrepancies between the effective doses determined from current recommendations and legal regulations and those determined from direct measurements of parameters affecting exposure.
Atmospheric radon is an ideal tracer that is widely used in atmospheric science. To meet the need fora continuous online measurement of atmospheric radon concentration, an upgraded radon monitor ...based on an electrostatic collection method was developed following Iida’s measurement system. Two major improvements have been realized. First, an 18 mm × 18 mm Si-PIN detector and a multi-channel analysis system were used to distinguish different alpha particles. Second, the P2O5 desiccant was replaced by a new membrane drying system, and the influence of humidity was corrected by a humidity correction coefficient. Calibration and comparison experiments were carried out in detail, and a one-year continuous measurement was also performed. Results showed that the measurement sensitivity was evaluated to be 24.3 cph/(Bq·m−3), and the lower level detection limit was 0.2 Bq·m−3 for a 1-h cycle at the absolute humidity of 0.34 g·m−3. The annual average radon concentration of Beijing was 11.1 ± 4.0 Bq·m−3, which changed from 2.8 Bq·m−3 to 30.3 Bq·m−3 between 15 October 2018 and 1 October 2019. The upgraded monitor’s high data acquisition rate and good performance indicate that it is suitable for long-term observation on atmospheric radon.
The permeability characteristics of overburden soil have a significant effect on radon exhalation in uranium tailings pond. To understand this change, the effects of dry density, particle size range, ...and moisture content on the gas permeability and radon exhalation were studied by correlation analysis method. According to the mechanism of radon generation, the permeability characteristics of overburden, and the weather conditions, a theoretical model of radon exhalation was constructed and an experimental setup was designed. A series of tests on different properties of overburden soil were conducted by uranium tailings permeameter, and the radon exhalation rate of corresponding overburden surface was measured by local static method. Results show that the permeability of overburden decreased, which led to the decrease of radon exhalation: (1) At the same moisture content, with the increase of dry density, both the gas permeability and radon exhalation rate decrease. (2) At the same moisture content, with the increase of the particle size range, both the gas permeability and radon exhalation rate increase. (3) At the same dry density, with the increase of moisture content, the gas permeability decreases, while the radon exhalation rate increases slightly at first and then decreases.
Coherent microwave radar is one of the effective devices for ocean wave measurements. However, the accuracy of wave inversion is significantly affected by the non-gravity wave components (referred to ...as non-wave components in this work) such as broken waves and shadows in the sea echoes. In this article, a new method based on the Radon transform and discrete Fourier transform (DFT) is proposed to suppress the non-wave components. First, the spatial-temporal velocities are calculated based on the raw data obtained from coherent microwave radar. Second, the Radon transform and DFT are performed on the spatial-temporal velocities to obtain the distribution of the spatial-temporal velocities in the Radon-Fourier transform domain. Following this, non-wave components are eliminated in accordance with the phase velocity and frequency distribution of the wave components. To validate the method, we analyzed the experimental data collected with a coherent S-band radar in Weihai in December 2021. After removing the non-wave components from the radar echoes, we invert three wave parameters including peak wave period, peak wave direction, and significant wave height and compare them with the in situ data. The results indicate that the method can effectively remove the non-wave components from the wave echoes without any empirical parameters.
In inverse synthetic aperture radar (ISAR) imaging, the high-resolution images can be obtained by using Range-Doppler algorithm. However, the rotational parts of the complex moving targets induce ...micro-Doppler (m-D) effects which influence the quality of ISAR imaging. In this Letter, a novel method of Radon-Laplace based on the Radon transform (RT) and the Laplace operator is proposed to reduce the m-D effect in ISAR imaging. For this method, the RT and Laplace operator are used to extract the rigid body parts in the short-time Fourier transform domain. Then, the rigid body parts can be got through a corresponding filter on the basis of the extraction results. The simulation and measured data results demonstrate the effectiveness of the proposed method.
Using a pooled case-control study design, including only never-smokers, we have assessed the association of residential radon exposure with the subsequent occurrence of lung cancer. We also ...investigated whether residential radon poses a different risk specifically for adenocarcinoma.
We pooled individual data from different case-control studies conducted in recent years in Northwestern Spain which investigated residential radon and lung cancer. All participants were never-smokers. Cases had a confirmed biopsy of primary lung cancer. Hospital controls were selected at pre-surgery units, presenting for non-complex surgical procedures. They were interviewed using a standardized instrument. Residential radon was measured using alpha track detectors at the Galician Radon Laboratory at the University of Santiago de Compostela.
A total of 1415 individuals, 523 cases and 892 controls were included. We observed an odds ratio of 1.73 (95%CI: 1.27–2.35) for individuals exposed to ≥ 200 Bq/m3 compared with those exposed to ≤100 Bq/m3. Lung cancer risk for adenocarcinoma was 1.52 (95%CI: 1.14–2.02) using the same categories for radon exposure.
Residential radon is a clear risk factor for lung cancer in never-smokers. Our data suggest that radon exposure is associated with all histological types of lung cancer and also with adenocarcinoma, which is currently the most frequent histological type for this disease.
•Lung cancer in never-smokers comprises approximately 15–25% of lung cancer cases.•The epidemiology of lung cancer in never-smokers is currently little developed.•Residential radon is a clear risk factor for lung cancer in never-smokers.•This risk is associated with almost all histological types of lung cancer.
PDF
