Indoor Radon Activity Concentration Research Articles

Measuring the real radon exhalation from walls in buildings

Building materials may significantly contribute to indoor radon activity concentration. Measuring the radon exhalation rate directly on the existing building elements represents the most accurate and reliable method to assess the building materials’ contribution. However, due to the method’s inner difficulties, no specific apparatus has been developed and documented in the literature.An innovative apparatus has been designed, constructed, and commissioned to measure the radon exhalation rate in situ from vertical surfaces of existing building walls. The apparatus is non-destructive, completely self-standing, and easily transportable. The sealing mechanism has been demonstrated to assure airtightness similarly to destructive setups. The measurements’ repeatability is less than 10% at different radon exhalation rates.The apparatus introduced is the only available solution to measure the site-dependent contribution of building materials to the indoor radon concentration. The apparatus allows for improving the specificity, so the effectiveness, of the remedial interventions to reduce the radon-related health risk.

Assessment of the residential radon concentrations in the Bakony Region, Hungary

ObjectiveTo investigate the current levels of indoor radon activity in the geologically complex Bakony Region of Hungary, which has been historically affected by industrial activities, and to identify areas that may require further monitoring and intervention. MethodsExperiments were carried out to measure quarterly indoor radon activity concentrations in ground-floor dwellings for a year using CR-39-type nuclear track detectors at 30 locations in 9 settlements to provide current information on the Bakony Region and identify areas requiring further attention. ResultsSince the annual average indoor radon activity concentration in the Bakony Region was 86 Bq/m3 and the maximum 274 Bq/m3, that is, less than the 300 Bq/m3 national and EU reference levels, it is considered safe. Two locations were equal to or exceeded the reference level during part of the year. While most of the Region exhibited high radon concentrations in the autumn and winter, two settlements presented inverse seasonal variations. ConclusionAlthough the autumn and winter values yielded a strong correlation with the annual mean and each other, this was not the case regarding the summer and spring values. The annual mean effective dose for the Region from the inhalation of radon and its progenies was estimated to be 2.2 ​mSv/year.

Experience from radon in soil gas comparison measurements held in Czech Republic and in other countries, 1992–2022

Radon 222Rn, an inert natural radioactive gas, a daughter product in the 238U natural decay series, a source of alpha radiation, together with its short-lived decay products is a dominant source of absorbed radiation doses in the population. Rocks and building materials are fundamental sources of radon in dwellings. Elevated indoor radon activity concentration in houses and workplaces, surpassing recommended reference levels, is not desirable. Since radon penetrates into the houses from the geological basement, various technical aids for protection of houses have been developed. Their individual application derives from the radon potential of a building site. Radon risk mapping of building sites became a standard procedure for gauging the local radon potential. Various instruments and techniques of measurements of radon activity concentration in soil gas (Bq/m3) at building sites are available. Since radon in soil gas and radon measurement techniques are affected by several natural and technical conditions, resultant values of radon risk mapping by individual organizations vary, sometimes fundamentally. Radon comparison measurements at selected reference sites are an important tool for single organizations to verify their radon measuring procedures and reliability of their reported results. Based on legislative regulations, comparison measurements at established radon reference sites are a part of the obligatory activities for radon risk mapping at building sites in the Czech Republic. Experience and analyses of 30-year radon in soil gas comparison measurements in the Czech Republic show the dispersion of values reported by participating organizations and indicate that more than 10% of participants do not fulfill the established local criteria. This paper introduces requirements for the establishment of radon reference sites, documents their natural variability, recommends the procedure of radon comparison measurement, and analyses its results. A long-term experience was gained by testing organizations from the Czech Republic (1992–2022) as well as from the international comparison measurements organized in the Czech Republic and in several other countries (2010–2021).

A closer look: Additional study of relationship between indoor radon exposure and the Covid-19 case fatality rate

In September 2022, the author of this text asked the scientific community an astonishing question: is there a connection between the Covid-19 case fatality rate and the radon exposure in interior spaces? And – if so – is it a correlation? Is it just a coincidence or even a causality? Radon exposure is particularly high in regions that have seen high mortality rates related to SARS-CoV-2. It was demonstrated that there is at least a correlation. This statement based on a comparison of four states of Germany. Of course, such a comparison is rather vague due to various geological situations. It is relatively rough, as the measures against the spread of the SARS-CoV-2 have been different from one state in Germany to another. Due to that, this paper takes a closer look to that phenomenon. It focuses on three districts in northern Bavaria: Ansbach, Bad Kissingen and Wunsiedel. The last one is situated close to Thuringia as well as the Czech Republic. It was declared as radon preservation area – the only one in Bavaria – and is rather affected by radon. Bad Kissingen represents a region with a medium average indoor radon activity concentration. It is located at the north at the border to Hesse. Ansbach is characterized of a lower risk to get affected by radon. It is in the vicinity to Baden Wuerttemberg in the west. Even this second comparison cannot provide a definitive answer to the questions named above. Nevertheless, this article will push that topic a little forward and by that support the answer to a possible relationship between indoor radon activity concentration and the Covid-19 case fatality rate. Possibly it puts little more focus more on radon protection than it happened during the pandemic years.

Successful reduction of indoor radon activity concentration via cross-ventilation: experimental data and CFD simulations

ABSTRACT Advanced computational fluid dynamics (CFD) simulations are essential for predicting airflow in ventilated spaces and assessing indoor air quality. In this study, a focus was set on techniques for the reduction of indoor radon-222 activity concentration [Rn], and it is demonstrated how true-to-scale 3D CFD models can predict the evolution of complex ventilation experiments. A series of ventilation experiments in an unoccupied flat on the ground floor of a residential block in Bad Schlema (Saxony, Germany) were performed. Specifically, the ‘Cross-ventilation 100 %’ experiment resulted in room-specific [Rn] reductions from ∼3000 to ∼300 Bq m−3. We quantitatively interpreted the results of the ventilation experiment using a CFD model with a k–ϵ turbulent stationary flow model characterised by the used decentralised ventilation system. The model was coupled with a transient transport model simulating indoor [Rn]. In a first approach, the model overestimated the decrease in the starting of the experiment and the steady state. Adjusting the model parameters inflowing radon and inlet velocity the model results are in a good agreement with the experimental values. In conclusion, this paper demonstrates the potential of CFD modelling as a suitable tool in evaluating and optimising ventilation systems for an effective reduction of elevated [Rn].

Evaluation of Indoor Radon Activity Concentrations and Controls in Dwellings Surrounding the Gold Mine Tailings in Gauteng Province of South Africa.

Radon in dwellings is recognized as the primary source of natural radiation exposure to members of the public. In the West Rand District and Soweto in the Gauteng Province (South Africa), indoor radon (222Rn) mapping was carried out to assess the exposure levels of radon in dwellings around gold and uranium mining tailings dams. This study was conducted predominately during warm and cold seasons, using the solid-state nuclear track detectors. In summer months, the indoor radon levels measured in all areas ranged from below the lower limit of detection to 71 Bq/m3, with a mean value of 29 Bq/m3, whereas in winter, the levels ranged between 11 and 124 Bq/m3, with a mean value of 46 Bq/m3. Higher indoor radon levels are found in colder months (winter season) than warmer months (summer season). However, no dwellings with indoor radon levels that exceed the WHO (2009) recommended reference level of 100 Bq/m3 were found, except for one that was constructed directly on soil mixed with tailings material. It is recommended that residents should keep their indoor radon levels low through continuous ventilation so as to minimize the buildup of radon and the likelihood of increased health hazards associated with radon exposure.

Development of a Pre-Diagnosis Procedure for the Evaluation of Indoor Radon Potential in Buildings

Indoor radon accumulation is considered the main source of human exposure to ionizing radiation. Depending on the average radon level, indoor long-term exposure can significantly increase the risk of lung cancer onset. The publication of international regulations on the protection of human health the exposure of ionizing radiation, defining threshold values over whom health consequences for occupants could be expected, led to the control and testing of radon levels in workplaces and premises using multiple techniques and approaches. In particular, since the main source of radon is soil, many efforts have been done for the redaction of maps of the geogenic potential risk, as well as the definition of proper measurement standards and techniques for indoor monitoring. Radon maps, based on geology and measurements of radon and/ or the natural radioactive content in the soil, constitute an evaluable tool for decision-making authorities in radon policies giving the possibility to characterize areas for radon risk where indoor radon measurements are not available. But, of course, they are not completely descriptive of the potential risk, so indoor monitoring in buildings is also required. The correct design of an indoor monitoring campaign is a crucial topic.. Scientific literature has largely demonstrated that many site-specific features influence the accumulation process, as well as most building materials represent a significant source, after the soil. The preliminary complete investigation in buildings should be properly defined since radiation safety in a situation of radon exposure completely ensured during the building's construction and maintenance phases as well as during the selling/rental ones. So, the aim of this work is to put the basis for the development of a pre-diagnosis procedure as a tool for the screening of buildings susceptible to high indoor radon activity concentrations. The work represents a very early stage of implementation of a qualitative method for the design of a measurement campaign for the indoor radon assessment. A pre-evaluation selection of the variables that play a leading role in the accumulation process is presented. A prior survey, based on evidence in scientific literature, was done to identify all relevant characteristics that most affect indoor radon levels, mainly concerning local geology, building features, ventilation, and occupancy factors. The selected parameters, classified into levels according to defined indicators and then combined, allow a more refined sample selection for measurements campaign in the indoor radon assessment process. Future development will be oriented to the validation of case studies and the implementation of the procedure in a software environment which will be the first tool available to systematize and regulate the radon monitoring process for short-term decision-making.

ISOradioLAb: an educational project on environmental radioactivity for Italian minor islands—the case study of Lampedusa and Linosa

ISOradioLAb is an educational project for schools of the Italian minor islands promoted by the Italian National Institute of Nuclear Physics. It aims to increase the population awareness of natural radioactivity by involving the students of the high schools in the measurement of indoor radon activity concentration in their schools and in some representative buildings. Within this project, questionnaires about risk perception and radon knowledge are also dispensed. With this approach students learn-by-doing and share their knowledge with friends and relatives. In this paper, we present the activities performed during the first year of the project, focused on the case study of the minor island of Lampedusa and Linosa, Agrigento (Italy). Questionnaires and radon measurements (using CR-39 and Electret) results are reported.

Indoor radon survey in Whitehorse, Canada, and dose assessment

Radon-222 (222Rn) and its decay products are the primary sources of a population’s exposure to background ionizing radiation. Radon decay products are the leading cause of lung cancer for non-smokers and the second leading cause of lung cancer after smoking for smokers. A community-driven long-term radon survey was completed in 232 residential homes in different subdivisions of Whitehorse, the capital of the Yukon, during the heating season from November to April in 2016–2017 and in 2017–2018. Radon concentrations were measured in living rooms and bedrooms on ground floors. The arithmetic and geometric means of indoor radon activity concentrations in different subdivisions of Whitehorse ranged from 52 ± 0.6 Bq m−3 and 37 ± 2.3 Bq m−3 in the Downtown area of Whitehorse to 993.0 ± 55.0 Bq m−3 and 726.2 ± 2.4 Bq m−3 in Wolf Creek. Underlying geology and glacial surfaces may partly explain these variations of indoor radon concentrations in subdivisions of Whitehorse. A total of 78 homes (34.0%) had radon concentrations higher than 100 Bq m−3, 47 homes (20.5%) had concentrations higher than 200 Bq m−3 and 33 homes (14.4%) had concentrations higher than 300 Bq m−3. The indoor radon contribution to the annual effective inhalation dose to residents ranged from 3.0 mSv in the Downtown area to 51.0 mSv in Wolf Creek. The estimated annual average dose to adults in Whitehorse, Yukon, is higher than the world’s average annual effective dose of 1.3 mSv due to the inhalation of indoor radon. The annual radon inhalation effective dose was assessed using radon measurements taken during winter; hence the assessed dose may be overestimated. Cost-efficient mitigation methods are available to reduce radon in existing buildings and to prevent radon entry into new buildings.

Indoor Radon Levels in Homes and Schools in the Western Cape, South Africa-Results from a Schools Science Outreach Initiative and Corresponding Model Predictions.

We describe a school science outreach initiative that introduced learners to applied nuclear physics research by means of a two-day workshop that involved learners and teachers from 5 schools in the Western Cape province of South Africa. During this workshop, the participants were introduced to the naturally occurring, inert, colorless, and tasteless radioactive gas radon (222Rn). During the first day of the workshop, the participants were informed about the detrimental health impacts of inhaling radon and its daughter radionuclides and were shown how indoor radon activity concentrations can be measured using the electret ion chamber (EIC) technology. The learners were then each supplied with a short-term electret (E-PERM, Radelec, Frederick, MD, USA) and associated ion chamber to enable them to make radon measurements in their homes. The teachers in turn were supplied with EICs to enable them make radon measurements in their schools. The participants returned the EICs on the second day of the workshop, one week later. Here, the drop in the potential difference across each electret was measured in order to calculate the average indoor radon activity concentration. A total of 49 indoor radon concentrations were measured. The average indoor radon concentrations were 36 ± 26 Bqm-3 in homes and 41 ± 36 Bqm-3 in schools, while the highest concentration was found to be 144 Bqm-3. These levels were compared to predictions from a model that uses input information about the uranium content associated with the surface geology at each measurement location. The predictions compared well with the measured values.

INDOOR RADON (222RN) MEASUREMENTS AND ESTIMATION OF ANNUAL EFFECTIVE DOSE IN MVANGAN LOCALITY, SOUTH CAMEROON.

The present work was aimed at measuring indoor radon activity concentrations in dwellings in Mvangan locality, South Cameroon, in order to assess the extent of measures that may be necessary for controlling public indoor radon exposure in this area. Measurements were carried out using passive solid-state nuclear track detectors (RADONAVA Inc., RadTrak2, Sweden) following ISO 11665-4 standard. Radon concentration ranged between 36±20 and 150±30Bqm-3 with arithmetic and geometric means values of 64±25 and 60±1Bqm-3, respectively. These mean values were greater than worldwide values presented by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), which are, respectively, 40 and 30Bqm-3. 96% of dwellings that have radon concentrations below the World Health Organization (WHO) reference level of 100Bqm-3, whereas 4% of dwellings have radon concentrations higher than this level but lower than 300Bqm-3, the International Commission on Radiological Protection (ICRP) reference level. Annual effective doses due to indoor radon ranged between 0.7 and 2.8mSv y-1 with an arithmetic mean value of 1.2±0.5mSv y-1. These values were below the lower limit of the ICRP-recommended action level interval 3-10mSv y-1. It has been observed that annual effective dose received by residents in cement bricks dwellings were not significantly different (P-value=0.565) than those received by residents in mud dwellings in Mvangan locality. The mean number of persons expected to be diagnosed with or die from cancer (solid cancers and leukemia) were 162±48 (61±25 for males and 101±41 for females) and 82±24 (33±13 for males and 49±20 for females), respectively. The results obtained in this study prove that the populations of Mvangan locality are exposed to a relatively low potential risk of cancer incidence and mortality.

RADON MONITORING IN SELECTED KINDERGARTENS IN SLOVAKIA.

In 17 kindergartens in Slovakia indoor radon survey was performed over a period of 1y. In selected kindergartens also continuous monitoring of indoor radon activity concentration was conducted for ~2 weeks, as well as soil radon measurements. Annual average of indoor radon concentration, measured using track detectors, ranged between 75 and 1810Bqm-3. Soil radon concentration ranged from 13 to 320kBqm-3. The relationship between activity concentrations measured in soil air and indoors has a linear character.

Health Effects of Natural Environmental Radiation during Burning Season in Chiang Mai, Thailand.

This paper presents the first measurement of the investigation of the health impacts of indoor radon exposure and external dose from terrestrial radiation in Chiang Mai province during the dry season burning between 2018 and 2020. Indoor radon activity concentrations were carried out using a total of 220 RADUET detectors in 45 dwellings of Chiang Mai (7 districts) during burning and non-burning seasons. Results show that indoor radon activity concentration during the burning season (63 ± 33 Bq/m3) was significantly higher (p < 0.001) compared to the non-burning season (46 ± 19 Bq/m3), with an average annual value of 55 ± 28 Bq/m3. All values of indoor radon activity concentration were greater than the national (16 Bq/m3) and worldwide (39 Bq/m3) average values. In addition, the external dose from terrestrial radiation was measured using a car-borne survey during the burning season in 2018. The average absorbed rate in the air was 66 nGy/h, which is higher than the worldwide average value of 59 nGy/h. This might be due to the high activity concentrations of 238U and 323Th in the study area. With regards to the health risk assessment, the effective dose due to indoor radon exposure, external (outdoor) effective dose, and total annual effective dose were 1.6, 0.08, and 1.68 mSv/y, respectively. The total annual effective dose is higher than the worldwide average of 1.15 mSv/y. The excess lifetime cancer risk and radon-induced lung cancer risk during the burning season were 0.67% and 28.44 per million persons per year, respectively. Our results substantiate that indoor radon and natural radioactive elements in the air during the burning season are important contributors to the development of lung cancer.

Decentralised ventilation efficiency for indoor radon reduction considering different environmental parameters

ABSTRACT Radon-222 contributes to half of the natural radiation exposure of humans and is one of the main causes of lung cancer. Of particular importance for humans is the exposure to radon-222 indoors, which enters living and working areas from the soil air, e.g. through cracks in the foundations of buildings. An easy and efficient way to minimise indoor radon in dwellings can be achieved through ventilation. How meteorological parameters and the geological background can influence ventilation efficiency in reducing indoor radon has not yet been fully investigated. Therefore, a decentralised ventilation system was installed in an unoccupied flat located in a former uranium mining region to analyse the effect of already existing ventilation modes on indoor radon activity concentration. It is aimed to assess 22 different ventilation experiments that were performed within the time period of one year. Even with a strong seasonal trend with significantly lower indoor radon activity concentrations in summer compared to winter, the decentralised ventilation system was able to reduce indoor radon by up to 83 %. Thereby, strong dependencies on the experimental parameters such as ventilation type or performance level of the fans were found.

Recent Progress in Radon Metrology at IFIN-HH, Romania

The practical implementation of the European Council Directive no. 2013/59/EURATOM in Romania requires reliable indoor measurements of the radon (222Rn) activity concentration in air. In Romania, several Testing Laboratories were designated for radon activity and/or radon activity concentration in air measurements by the Romanian National Commission for Nuclear Activities Control (CNCAN). The calibration of the instruments used for indoor radon activity concentration measurements is very important. IFIN-HH, through its Ionizing Radiation Metrology Laboratory (LMRI), performed advanced research in the field of radon metrology, using radon standard sources prepared by LMRI, its radon chamber facility and a new reference radon monitor. The most recent results are described in this article. The radon chamber facility from IFIN-HH was technically improved, and new equipment and methods were set up and tested in order to provide new calibration services for customers. Additionally, calibration of the radon monitors was performed, as well as of the systems with solid-state nuclear track detectors, used for radon in air activity concentration measurements. IFIN-HH/LMRI obtained the CNCAN designation as Calibration Laboratory for installations measuring the radon activity concentration in air.

Inter-comparison of commercial continuous radon monitors responses

Indoor and outdoor (atmospheric) radon activity concentrations need to be measured as accurate as possible for radiation protection and for climate applications. Particularly radon concentrations below 100 Bq m −3, useful for the retrieval of radon prone areas and for atmospheric studies, still need a robust metrological chain to ensure their quality. Ones of the most common used commercial continuous radon monitors were compared here under slightly different environmental conditions. The measured data set were divided into two groups (< 100 Bq m −3 and ≥ 100 Bq m −3) to assess the monitors responses and their associated uncertainties. Nevertheless, these results should also to point out if commercial monitors are suitable for monitoring low atmospheric radon concentrations with an associated uncertainty of 10% (k=1). This work, carried out within the EMPIR 19ENV01 traceRadon project, aims to offer a starting point for the development of a future radon monitor as transfer standard to increase the metrological capabilities of atmospheric radon monitoring.

A Comparative Study on Indoor Radon Levels between the Lung Cancer and Cancer Free Groups in Izmir Province, Turkey

Purpose: İzmir is the province of Turkey with the highest lung cancer incidences for males, therefore a comparative study was performed in particular districts of İzmir in 2013. In the study, it was aimed to assess the association between lung cancer risk and indoor radon. &#x0D; Methods: Patients diagnosed with lung cancer between 2010 and 2011 were selected from the database of the Izmir Cancer Registry (ICR). Measurements of indoor radon concentrations were performed in a total of 117 locations using the SSNTD (Solid State Nuclear Track Detectors) method with LR-115 detectors. Indoor radon concentration measured in homes of patients with lung cancer and cancer free group were compared statistically. &#x0D; Results: The indoor Radon (222Rn) activity concentration detected ranged from 165 to 487 Bq/m3, for the lung cancer group, from 28 to 367 Bq/m3 for the cancer free group, with geometric means of 269 Bq/m3 and 123 Bq/m3, respectively.&#x0D; Conclusion: According to the logistic regression model, as radon concentration and package/year increased, the rate of cancer increased multiple folds. These results suggest that indoor radon levels may contribute to higher rates of lung cancer for İzmir compared to the rest of the country, and indoor radon levels may be a contributory factor in this phenomenon.

Assessment of indoor radon activity concentration levels in four northern districts of Telangana state, India

Assessment of indoor radon activity concentration levels in four northern districts of Telangana state, India

Indoor radon, external dose rate and assessment of lung cancer risk in dwellings: the case of Ebolowa town, Southern Cameroon

ABSTRACT The present work reports indoor Radon-222 activity concentration measurements, external gamma dose rate measurements, and assessment of cancer risk in the different dwellings in Ebolowa town, southern Cameroon. The geological formations of this studied area are mainly granites. This studied area extends over the equatorial climatic zone. The mean temperature of the zone varies from 25°C to 26°C with two rainy and two dry seasons with a relative humidity of (70–80) % recorded throughout the year. The indoor radon activity concentrations were carried out using RADTRACK2 devices, which are the alpha track detectors made of CR-39 plastic films contained in an antistatic black holder. Each device was hung in an inhabited room of each selected dwelling for an average period of three months. Radon concentrations in dwellings ranged between (23 ± 10) Bq m–3 and (2620 ± 480) Bq m–3 with an arithmetic mean of 135.6 Bq m–3 and a geometric mean of 63 Bq m–3. The estimated annual effective doses due to external gamma exposure ranged from (0.15 ± 0.01) mSv y−1 to (0.38 ± 0.06) mSv y−1 with an average value of 0.26 mSv y−1. The estimated annual effective dose due to indoor radon ranged between 0.43 mSv y−1 and 49.6 mSv y−1 with an arithmetic mean of 2.6 mSv y−1. This value was below the International Commission on Radiological Protection (ICRP) recommended action level. The Excess Lifetime Cancer Risk (ELCR) ranged from 1.39% to 158% with a mean value of 8.2%. According to these results, cancer risk due to inhalation of radon-222 must be further investigated in the population living in Ebolowa town.

Estimation of radon excess lung cancer near some dumpsites in, Lagos, Nigeria

Generally, in Nigeria dumpsites are open and elevate the pollution by increasing the total environment contamination level. This affects not only the site of dumpsites but also the surrounding buildings and area. In the present work, indoor radon activity concentration is tested inside some buildings in the vicinity of dumpsites in Lagos, Nigeria. A passive technique with CR-39 detectors is used. Different buildings around different eight dumpsites were chosen. Radon concentration had ranged from 16.00 ± 3 to 931.00 ± 186 Bqm−3 in the dumpsites. With Mean concentrations range from 120 ± 24 at OKE-ODO to 334 ± 67, at Solus-4 respectively. The present results explain that 63% of the radon activity concentration in indoor air around the selected dumpsites at Lagos city in Nigeria is below the allowed limit from ICRP 200 Bq m-3 while 37% is more than this limit. Based on the measured radon concentration, the annual effective dose and cancer risk are evaluated. The range of ELC is from 242 to 14086 with mean value 3114 ± 1111.