Influencing Indoor Radon Research Articles

Unintended Consequences of Urban Expansion and Gold Mining: Elevated Indoor Radon Levels in Gauteng Communities’ Neighboring Gold Mine Tailings

The province of Gauteng in South Africa has a rich history of gold mining, which has driven economic growth and urbanization. Gold mining has also created over 270 gold mine tailings (GMT), now surrounded by human settlements due to a housing shortage. These GMT pose a health risk as they harbor elevated uranium, which over time undergoes radioactive decay to produce radon, a known lung carcinogen. This study aimed to investigate the potential correlation between the proximity to gold mine tailings (GMT) and indoor radon concentrations in Gauteng’s residential dwellings. Volume activity of radon (VAR) inside 330 residential dwellings was measured in residential dwellings located proximally (<2 km) and distally (>2 km) to gold mine tailings using AlphaE radon monitors during winter. An interviewer-administered questionnaire was utilized to obtain data on factors that may influence indoor radon activities. Descriptive statistics and bivariate logistic regression analyzed the influence of proximity to gold mine tailings and dwelling characteristics on VAR. Furthermore, VAR was compared to the World Health Organization (WHO) radon reference level of 100 Bq/m3. Residential dwellings near gold mine tailings had significantly higher average indoor radon concentrations (103.30 Bq/m3) compared to the control group (65.19 Bq/m3). Residential dwellings proximal to gold mine tailings were three times more likely to have VAR beyond the WHO reference level of 100 Bq/m3. Furthermore, they had estimated annual effective doses of 2.60 mSv/y compared to 1.64 mSv/y for the control group. This study highlighted a concerning association between proximity to gold mine tailings and elevated indoor radon levels. Public health interventions prioritizing residential dwellings near gold mine tailings are crucial. Educational campaigns and financial assistance for radon mitigation systems in high-risk dwellings are recommended. Residents near gold mine tailings are encouraged to ensure continuous natural ventilation through frequent opening of windows and doors.

Techniques to mitigate the admission of radon inside buildings

Abstract In this work, the factors that influence indoor radon (Rn) level and most usual methods to prevent or mitigate Rn are presented and discussed, according to their way of action. The findings show that it is possible to select the most appropriate and effective solutions for each situation, even in cases where there is a high risk of Rn concentration, by combining these methods to increase overall efficiency. Finally, most relevant strategic recommendations are presented to guarantee the success of Rn protection measures, to reduce problems associated with Rn.

Evaluation of radon‐induced radiation risk in indoor environments

AbstractIn general people spend most of their time in enclosed environments, therefore, they are exposed to indoor radon and its progeny. The paper discusses the variables influencing indoor radon levels. It assesses the correlation between indoor radon levels with temperature, humidity, and pressure, as well as seasonal variables. Radon activity concentrations were measured in Ege University's laboratories and Classroom using a digital radon gas detector. After statistical analysis, the results were compared to committee‐permissible limit levels (ICRP, WHO, and EU). It was found that the average radon activity concentrations were below the recommended 300 Bq m–3 limit value (EU), ranging from 58.4 to 216.0 Bq m–3. This study emphasized the significance of measuring and assessing the indoor radon levels in laboratories and classrooms in particular, in order to safeguard the students and faculty members from radon‐related health issues.

Exploring statistical and machine learning techniques to identify factors influencing indoor radon concentration

Radon is a radioactive gas with a carcinogenic effect. The malign effect on human health is, however, mostly influenced by the level of exposure. Dangerous exposure occurs predominantly indoors where the level of indoor radon concentration (IRC) is, in its turn, influenced by several factors. The current study aims to investigate the combined effects of geology, pedology, and house characteristics on the IRC based on 3132 passive radon measurements conducted in Romania. Several techniques for evaluating the impact of predictors on the dependent variable were used, from univariate statistics to artificial neural network and random forest regressor (RFR). The RFR model outperformed the other investigated models in terms of R2 (0.14) and RMSE (0.83) for the radon concentration, as a dependent continuous variable. Using IRC discretized into two classes, based on the median (115 Bq/m3), an AUC-ROC value of 0.61 was obtained for logistic regression and 0.62 for the random forest classifier. The presence of cellar beneath the investigated room, the construction period, the height above the sea level or the floor type are the main predictors determined by the models used.

Study of radium content and radon exhalation rates in raw building materials used in southern India

As a potential source of indoor radiation arising from radon, a range of building materials (white cement, gray cement, gravel, gypsum, granite, marble, vitrified tile, and brick) were studied for the specific activity of radium and radon gas exhalation rates. The activity of radium was determined using scintillation gamma-ray spectrometry. Exhalation rates were assessed using passive and active measurement methods. Radon mass exhalation rates from powdered building materials and radon surface exhalation rates from slab-type building materials were measured. Activity concentrations of 226Ra in powder and slab-type building materials were found in the range of (1.12 – 14.98) Bqkg−1 and (17 – 308) Bqkg−1, respectively. 222Rn mass exhalation rates (mBqkg−1h−1) from the building materials were in the range of 15.0 ± 0.8 (gray cement) to 1.1 ± 0.1 (gravel). Surface exhalation rates (mBqm−2h−1) for slab-type materials have a range of 317 ± 9 (brick) to 8 ± 2 (marble). Strong positive correlations were found between the specific activity of radium and radon mass exhalation rates (r = 0.9408) and radon surface exhalation rates (r = 0.7167) for building materials investigated. Obtained data indicates that the building materials used influence indoor radon concentration in dwellings.

A Preliminary Study of the Characteristics of Radon Data from Indoor Environments and Building Materials in the Campania Region Using PCA and K-Means Statistical Analyses

For a healthy indoor environment, it is important to understand which materials and factors favor the generation of high levels of indoor radon. A preliminary multivariate statistical analysis was carried out on two datasets concerning indoor radon and building materials in the Campania Region using Principal Component Analysis (PCA) and the k-means partitional analysis technique. A total of 13 parameters related to building materials were used. The results show the greater contribution of building materials of volcanic origin to the concentration of indoor radon and thoron activity and the different influence of the parameters of the 31 materials analyzed. The same analyses applied to the indoor radon values of 694 rooms in the Campania Region were equally effective in assessing the structural characteristics of indoor environments that most influence indoor radon levels. The study provided an effective assessment of the influence on radon activity of several environmental parameters, which are often not adequately considered.

DETAILED INDOOR RADON SURVEY IN DWELLINGS OF PROVISIONAL RADON-PRONE AREAS IN KOREA.

The objective of this study is to determine indoor radon concentrations for 11 counties in Korea, develop a detailed radon distribution map and compare the results by some factors influencing indoor radon levels. The radon survey was conducted for 7y in provisional radon-prone areas selected based on the previous national surveys. The total number of samples was >2.5% of the entire dwellings by each county. The annual average indoor radon concentration for the survey areas had a geometric mean of 94Bqm-3 with 6.6% of all sampled dwellings showing values exceeding 300Bqm-3. Some areas with relatively high indoor radon concentration were identified through a spatial distribution map. Seasonal variations were observed with commonly the highest concentration in winter, and house characteristics influencing indoor radon levels. This study can serve as a basis for developing national radon action plans and guide for additional regional radon surveys.

Estimation of lung cancer deaths attributable to indoor radon exposure in upper northern Thailand

Radon exposure is the second leading cause of lung cancer, after smoking. In upper northern Thailand (UNT), lung cancer incidence was frequently reported by Thailand National Cancer Institute. Besides smoking, radon exposure may also influence the high lung cancer incidence in this region. Indoor radon concentrations were measured in 192 houses in eight provinces of UNT. Indoor radon concentrations ranged from 11 to 405 Bq m−3 and estimated annual effective dose ranged from 0.44 to 12.18 mSv y−1. There were significant differences in indoor radon concentrations between the houses of lung cancer cases and healthy controls (p = 0.033). We estimated that 26% of lung cancer deaths in males and 28% in females were attributable to indoor radon exposure in this region. Other factors influencing indoor radon levels included house characteristics and ventilation. The open window-to-wall ratio was negatively associated with indoor radon levels (B = −0.69, 95% CI −1.37, −0.02) while the bedroom location in the house and building material showed no association. Indoor radon hence induced the fractal proportion of lung cancer deaths in UNT.

Indoor Radon Concentration and Risk Estimation: the EURA PROJECT

The indoor radon concentration level has been monitored in selected locations in four European countries (Iceland, Italy, Norway, and Sweden) during a yearlong measurement campaign using time-integrated passive radon dosimeters containing CR-39 track detectors. The measurements were carried out in private houses and public buildings like schools, for an exposure time of up to 6 months for each detector. Experimental data shows a great variation between different geographic areas, and often the average levels are over the acceptable radon limit of 300 Bq/m3recommended by the International Commission on Radiological Protection (ICRP). To investigate a relationship between indoor radon exposure and lung cancer, estimating the cumulative levels of exposure to indoor radon for an individual or population is necessary. We analyse the data sets and investigate the factors influencing indoor radon concentrations in order to determine the best use of the experimental information. The results show that the variables associated with indoor radon levels are strictly linked to the soil geology. Analyzing the data sets enables improved assessment of radon exposure in a given area. The average absorption effective dose equivalent for a person is computed, and the risk of lung cancer per year is evaluated. Doi: 10.28991/HEF-2021-02-04-01 Full Text: PDF

Factors influencing temporal variations of radon concentration in high-rise buildings

Long-term radon time series were analyzed in 14 rooms and offices to search factors influencing indoor radon concentration in high-rise buildings. Radon entry to living rooms is determined both by diffusion from building materials and advection from adjoined low-ventilated spaces. Humans affect on seasonal and diurnal radon concentration changes in high-rise buildings by activating ventilation system. Indoor-outdoor temperature difference significantly influence on the air exchange rate under uncontrolled ventilation, which is especially important in new energy efficient buildings.

RADON TIME SERIES IN FOUR FLATS IN ENERGY EFFICIENT MULTI-STOREY BUILDING.

Influence of living habits and meteorological parameters on indoor radon concentration in a new energy efficiency multi-storey flat building typical for Russian cities was studied using radon time series analysis. Continuous indoor radon measurements were conducted in four flats of the same multi-storey residential building in Ekaterinburg, Russia. Factors influencing indoor radon in surveyed building (by rank) are as follows: ventilation regime> indoor/outdoor temperature difference>wind direction. Intentional ventilation frequency, temperature difference and wind direction explain together up to 46% of indoor radon variability in a flat of multi-storey building.

Identifying indoor radon sources in Pa Miang, Chiang Mai, Thailand

Radon is the leading source of lung cancer mortality after smoking in Chiang Mai, Thailand. Finding a source of carcinogens is one of the important measures for preventing the cancer risk for this region. Specific sites at Pa Miang, Doi Saket have the highest incidences of lung cancer and have a combination of factors that influence indoor radon concentration. Our study identified the sources of indoor radon within several houses. The results indicate that geological and topographic characteristics, including active faults and mountain terraces, are the main sources of indoor radon, especially for wooden houses. Besides building materials, the design of the houses, ventilation conditions, and lifestyle choices are all factors influencing indoor radon concentrations and its associated risk. Although radon levels (29–101 Bq m−3) and total indoor annual effective doses (0.9–3.8 mSv year−1) received from all sources at these sites have shown no significant health risk due to radon exposure , this investigation will be useful as a starting point to guide strategies to respond and prevent the risk of lung cancer, especially in Chiang Mai.

The Influence of Internal Wall and Floor Covering Materials and Ventilation Type on Indoor Radon and Thoron Levels in Hospitals of Kermanshah, Iran.

BackgroundBuilding materials and the ventilation rate of a building are two main factors influencing indoor radon and thoron levels (two radioactive gases which have the most important role in human natural radiation exposure within dwellings).ObjectivesThis analytical descriptive study was intended to determine the relationship between indoor radon and thoron concentrations and the building materials used in interior surfaces, as well as between those concentrations and the type of ventilation system (natural or artificial).Materials and Methods102 measurements of radon and thoron levels were taken from different parts of three hospital buildings in the city of Kermanshah in the west of Iran, using an RTM-1688-2 radon meter. Information on the type of building material and ventilation system in the measurement location was collected and then analyzed using Stata 8 software and multivariate linear regression.ResultsIn terms of radon and thoron emissions, travertine and plaster were found to be the most appropriate and inappropriate covering for walls, respectively. Furthermore, granite and travertine were discovered to be inappropriate materials for flooring, while plastic floor covering was found suitable. Natural ventilation performed better for radon, while artificial ventilation worked better for thoron.ConclusionsInternal building materials and ventilation type affect indoor radon and thoron concentrations. Therefore, the use of proper materials and adequate ventilation can reduce the potential human exposure to radon and thoron. This is of utmost importance, particularly in buildings with a high density of residents, including hospitals.

Factors influencing indoor radon concentration in detached houses

Factors influencing indoor radon concentration in detached houses

Attributable risk of lung cancer deaths due to indoor radon exposure.

Exposure to radon gas is the second most common cause of lung cancer after smoking. A large number of studies have reported that exposure to indoor radon, even at low concentrations, is associated with lung cancer in the general population. This paper reviewed studies from several countries to assess the attributable risk (AR) of lung cancer death due to indoor radon exposure and the effect of radon mitigation thereon. Worldwide, 3–20 % of all lung cancer deaths are likely caused by indoor radon exposure. These values tend to be higher in countries reporting high radon concentrations, which can depend on the estimation method. The estimated number of lung cancer deaths due to radon exposure in several countries varied from 150 to 40,477 annually. In general, the percent ARs were higher among never-smokers than among ever-smokers, whereas much more lung cancer deaths attributable to radon occurred among ever-smokers because of the higher rate of lung cancers among smokers. Regardless of smoking status, the proportion of lung cancer deaths induced by radon was slightly higher among females than males. However, after stratifying populations according to smoking status, the percent ARs were similar between genders. If all homes with radon above 100 Bq/m3 were effectively remediated, studies in Germany and Canada found that 302 and 1704 lung cancer deaths could be prevented each year, respectively. These estimates, however, are subject to varying degrees of uncertainty related to the weakness of the models used and a number of factors influencing indoor radon concentrations.

An Investigation of Factors Influencing Indoor Radon Concentrations in Dwellings of Northern Rajasthan, India

Abstract An effort has been made to find possible relationships of indoor radon levels with building construction materials, ventilation condition of dwellings and soil gas radon levels. Indoor radon measurements were made using LR-115 type II cellulose nitrate films and the concentrations were estimated by knowing the track density of films through optical microscope. Soil gas radon levels were measured using RAD7, an electronic radon detector manufactured by Durridge Company, USA. This study sheds light on the seasonal indoor radon activities in Rajasthan dwellings. Maximum values of the indoor radon concentration were observed during the winter and minimum during the summer season. Results show that ventilation rate is inversely proportional to radon level. Highest level of indoor radon concentration was found in the mud type dwellings compared with dwellings made of concrete, cement and marble. A positive correlation (R2 = 0.45) between indoor radon and soil gas radon concentration was observed. A weak positive correlation (R2 = 0.22) was observed between soil gas radon concentration and radium content in soil. Indoor radon concentration was found to be associated with the presence of radon concentration in local soil, building material used for roof, floor and walls, type of ventilation conditions and presence of cracks on the walls/floor. Positive correlation between indoor and soil gas radon concentration suggest the large contribution of local soil towards indoor radon.

A statistical evaluation of the influence of housing characteristics and geogenic radon potential on indoor radon concentrations in France

Radon-222 is a radioactive natural gas produced by the decay of radium-226, known to be the main contributor to natural background radiation exposure. Effective risk management needs to determine the areas in which the density of buildings with high radon levels is likely to be highest. Predicting radon exposure from the location and characteristics of a dwelling could also contribute to epidemiological studies. Beginning in the nineteen-eighties, a national radon survey consisting in more than 10,000 measurements of indoor radon concentrations was conducted in French dwellings by the Institute for Radiological Protection and Nuclear Safety (IRSN). Housing characteristics, which may influence radon accumulation in dwellings, were also collected. More recently, the IRSN generated a French geogenic radon potential map based on the interpretation of geological features. The present study analyzed the two datasets to investigate the factors influencing indoor radon concentrations using statistical modeling and to determine the optimum use of the information on geogenic radon potential that showed the best statistical association with indoor radon concentration. The results showed that the variables associated with indoor radon concentrations were geogenic radon potential, building material, year of construction, foundation type, building type and floor level. The model, which included the surrounding geogenic radon potential (i.e. the average geogenic radon potential within a disc of radius 20 km centered on the indoor radon measurement point) and variables describing house-specific factors and lifestyle explained about 20% of the overall variability of the logarithm of radon concentration. The surrounding geogenic radon potential was fairly closely associated with the local average indoor radon concentration. The prevalence of exposure to radon above specific thresholds and the average exposures to radon clearly increased with increasing classes of geogenic radon potential. Combining the two datasets enabled improved assessment of radon exposure in a given area in France.

Establishing a regional reference indoor radon level on the basis of radon survey data

The establishment of national reference levels is a new requirement of the ICRP radiological protection system. For protection against indoor radon exposure measures based on a common national reference level tend to be less effective in regions where the probability of high indoor radon concentrations is relatively low in comparison with the national average. Therefore it makes sense to establish individual indoor radon reference levels for large sub-national regions as well as for urban agglomerations separately. Analysis of indoor radon surveys of the territory, taking into account the type of building, year of construction, building material, floor and other factors influencing indoor radon concentration, provides essential and important data for defining the reference level. For Ekaterinburg, Russia it is suggested to set the reference indoor radon concentration to a level of 70 Bq m−3 which corresponds to the 90th percentile of radon concentration in a representative group of buildings constructed in the period 1970–89, in which the lowest average indoor radon concentration was observed.

Influence of indoor air conditions on radon concentration in a detached house

Radon is released from soil and building materials and can accumulate in residential buildings. Breathing radon and radon progeny for extended periods hazardous to health and can lead to lung cancer. Indoor air conditions and ventilation systems strongly influence indoor radon concentrations. This paper focuses on effects of air change rate, indoor temperature and relative humidity on indoor radon concentrations in a one family detached house in Stockholm, Sweden.In this study a heat recovery ventilation system unit was used to control the ventilation rate and a continuous radon monitor (CRM) was used to measure radon levels. FLUENT, a computational fluid dynamics (CFD) software package was used to simulate radon entry into the building and air change rate, indoor temperature and relative humidity effects using a numerical approach.The results from analytical solution, measurements and numerical simulations showed that air change rate, indoor temperature and moisture had significant effects on indoor radon concentration. Increasing air change rate reduces radon level and for a specific air change rate (in this work Ach = 0.5) there was a range of temperature and relative humidity that minimized radon levels. In this case study minimum radon levels were obtained at temperatures between 20 and 22 °C and a relative humidity of 50–60%.

How Do Different Locations, Floors and Aspects Influence Indoor Radon Concentrations? An Empirical Study Using Neural Networks for a University Campus in Northwestern Turkey

Indoor radon (222Rn) concentrations were measured at a 10-min interval during October 2011 and January 2012. The monitoring followed a randomised and repeated pattern of experimental design, and was carried out at six faculty buildings of the Abant Izzet Baysal University, on five floor levels and two aspect directions (south vs. north) using an AlphaGUARD P30 Radon Monitor. The University campus area located in northwestern Turkey is near the North Anatolian Fault, a major active right lateral-moving strike-slip fault which runs along the transform boundary between the Eurasian Plate and the Anatolian Plate. Best artificial neural networks (ANNs) emulating indoor 222Rn levels were selected as a function of air temperature ( Ta), air pressure ( Pa), relative humidity (RH), Ta by RH interaction, local time, location, floor and aspect. Elevated levels of indoor 222Rn concentrations were measured at the south-facing offices and on the first floor levels of the building. Lower concentrations were found on the upper floor levels. Out of 27 ANNs, GFF-1-B-L and MLP-2-B-L performed best and could be contributing to the 35.6% and 87.2% of variations in spatio-temporal dynamics of indoor 222Rn levels as a function of location or floor level and aspect, respectively, in addition to Ta, Pa, RH, Ta by RH interaction and time.