High Radon Levels Research Articles

Radon Concentration Measurement in Ainkawa Region Using Solid State Nuclear Track Detector

Radon is the air contaminant radioactive gas which people exposed to, is a reason for lung damages and lung cancer. The areas that are subject to high radon levels are found by radon concentration measurement. The radon activity concentration, annual effective dose, and potential alpha energy concentration (PAEC), were measured in houses of Ainkawa region using CR-39 solid state nuclear track detectors SSNTDs with the sealed-can technique. In the present paper the estimated values for radon activity concentration are in the range 55.99-112.8 Bq/m 3 with 84.30 Bq/m 3 as a mean value, the range of annual effective dose are 1.411-2.872 mSv/y , with mean value 2.124 mSv/y , and the potential alpha energy concentration range are 6.0533-12.323 mWL with mean of 9.1133 mWL . The mean value of the radon concentration is below of 100 Bq/m 3 the reference level of (WHO) World Health Organization, and well below of UK National Radiation Protection Board (NRPB) and European Commission Recommendation Level of 200 Bq/m 3 .

A statewide investigation of geographic lung cancer incidence patterns and radon exposure in a low-smoking population

BackgroundLung cancer is the leading cause of cancer-related mortality in Utah despite having the nation’s lowest smoking rate. Radon exposure and differences in lung cancer incidence between nonmetropolitan and metropolitan areas may explain this phenomenon. We compared smoking-adjusted lung cancer incidence rates between nonmetropolitan and metropolitan counties by predicted indoor radon level, sex, and cancer stage. We also compared lung cancer incidence by county classification between Utah and all SEER sites.MethodsSEER*Stat provided annual age-adjusted rates per 100,000 from 1991 to 2010 for each Utah county and all other SEER sites. County classification, stage, and sex were obtained from SEER*Stat. Smoking was obtained from Environmental Public Health Tracking estimates by Ortega et al. EPA provided low (< 2 pCi/L), moderate (2–4 pCi/L), and high (> 4 pCi/L) indoor radon levels for each county. Poisson models calculated overall, cancer stage, and sex-specific rates and p-values for smoking-adjusted and unadjusted models. LOESS smoothed trend lines compared incidence rates between Utah and all SEER sites by county classification.ResultsAll metropolitan counties had moderate radon levels; 12 (63%) of the 19 nonmetropolitan counties had moderate predicted radon levels and 7 (37%) had high predicted radon levels. Lung cancer incidence rates were higher in nonmetropolitan counties than metropolitan counties (34.8 vs 29.7 per 100,000, respectively). Incidence of distant stage cancers was significantly higher in nonmetropolitan counties after controlling for smoking (16.7 vs 15.4, p = 0.02*). Incidence rates in metropolitan, moderate radon and nonmetropolitan, moderate radon counties were similar. Nonmetropolitan, high radon counties had a significantly higher incidence of lung cancer compared to nonmetropolitan, moderate radon counties after adjustment for smoking (41.7 vs 29.2, p < 0.0001*). Lung cancer incidence patterns in Utah were opposite of metropolitan/nonmetropolitan trends in other SEER sites.ConclusionLung cancer incidence and distant stage incidence rates were consistently higher in nonmetropolitan Utah counties than metropolitan counties, suggesting that limited access to preventative screenings may play a role in this disparity. Smoking-adjusted incidence rates in nonmetropolitan, high radon counties were significantly higher than moderate radon counties, suggesting that radon was also major contributor to lung cancer in these regions. National studies should account for geographic and environmental factors when examining nonmetropolitan/metropolitan differences in lung cancer.

An analysis of radon levels in the basements of UK workplaces and review of when employers should test

Radon is a recognised lung carcinogen. The main source of radon in UK buildings is the ground. As basements have more ground contact than other parts of a building, and often limited ventilation, there is increased potential for high radon levels to occur. Regulations are in place in the UK to control radon exposure at work, to prompt employers to undertake risk assessments, test where necessary and take action if levels exceed certain thresholds. Both Public Health England (PHE) and the Health and Safety Executive (HSE) currently advise employers to test routinely occupied basements for radon, irrespective of geographical location; the minimum annual occupancy threshold has been established as one hour per week (approximately 50 h per year). PHE operates a routine measurement service for employers and holds the measurement data for radon levels in the basements of more than 3500 workplaces. Typically, radon concentrations follow a lognormal distribution over a wide range, when corrections are made for seasonal variations and the contribution of outside air. Statistical tests on these data show good correspondence in most cases for the workplace basements of seven different occupational sectors. Radon should be included in the risk assessments of basements of all workplace types irrespective of the radon-affected area status (i.e. whether they are located in a geographical unit where higher proportions of houses or workplaces are likely to exceed their reference levels). As a consequence of this analysis, however, evidence is presented that supports a change in the existing protocols on when to test the radon levels in basements, if a more sophisticated approach were to be adopted taking into account the affected area status.

Radon Exposure-induced Genetic Variations in Lung Cancers among Never Smokers.

BackgroundLung cancer in never smokers (LCINS) differs etiologically and clinically from lung cancer attributed to smoking. After smoking, radon exposure is the second leading cause and the primary risk factor of lung cancer among never smokers. Exposure to radon can lead to genetic and epigenetic alterations in tumor genomes affecting genes and pathways involved in lung cancer development. The present study sought to explore genetic alterations associated with LCINS exposed to radon gas indoors.MethodsGenetic associations were assessed via a case-control study of LCINS (39 cases and 30 controls) using next generation sequencing. Associations between genetic mutations and high exposure to radon were investigated by OncoPrint and heatmap graphs. Bioinformatic analysis was conducted using various tools. According radon exposure levels, we divided subjects in two groups of cases and controls.ResultsWe found that ABL2 rs117218074, SMARCA4 rs2288845, PIK3R2 rs142933317, MAPK1 rs1803545, and androgen receptor (AR) rs66766400 were associated with LCINS exposed to high radon levels. Among these, Chromodomain helicase DNA-binding protein 4 (CHD4) rs74790047, TSC2 rs2121870, and AR rs66766408 were identified as common exonic mutations in both lung cancer patients and normal individuals exposed to high levels of radon indoor.ConclusionWe identified that CHD4 rs74790047, TSC2 rs2121870, and AR rs66766408 are found to be common exonic mutations in both lung cancer patients and normal individuals exposed to radon indoors. Further analysis is needed to determine whether these genes are completely responsible for LCINS exposed to residential radon.

A national survey on radon remediation in Switzerland

We present and discuss the results of a national survey on radon remediation. The main purpose of the survey was to evaluate the rate of radon remediation in Switzerland and to identify the main reasons for not taking action in cases of high radon levels. Switzerland is strongly affected by radon problems and extensive efforts have been made to map the radon potential and to investigate the most effective methods to reduce radon levels in different buildings. However, since the radon remediation of buildings has been given over to experts in the private sector, and since there is no obligation to report a finished remediation to the authorities, it is difficult for the Federal Office for Public Health (FOPH) to track activities in this field. In order to improve this situation, the FOPH has launched a survey. We find a radon remediation rate of 46%. The most often applied method is aeration of the cellar and improvement in the tightness of floor slabs. The respondents indicate that concerns regarding the financial and/or invasive magnitude of the work are the most significant reasons for not taking action. We discuss the different outcomes of the survey in the three linguistic regions in Switzerland and identify aspects of our communication with the public, which should be improved in view of our findings.

Radon gas: Risks, regulations and remediation

Exposure to radon gas is the second leading cause of lung cancer worldwide. Radon can accumulate unnoticed within buildings, so it is vital that properties at risk are tested and action is taken to reduce high concentrations where present. Many people remain unaware of radon and only learn about it when purchasing a property, as it is covered in various conveyance documents. High radon levels in existing buildings can be mitigated and new properties can be protected from radon intrusion with careful design and workmanship. This paper discusses why it is important to protect people from radon exposure, the laws that exist to limit exposure in certain situations and the methods that can be employed in both existing and newbuilds to do so. The impact of modern energy-efficient building designs is also addressed.

An experimental and numerical study on radon transport from UMT-contaminated sand to a house basement under variable weather conditions

Numerical modelling is necessary in order to better understand transient phenomena of radon transport from radium-contaminated soils to a house basement where high radon levels were observed. The present work aims to develop a robust and simplified subsurface numerical model which can simulate radon transport at the soil-basement foundation interface under variable weather conditions around a house. The equivalent continuum modelling (ECM) approach has been used assuming an equivalent porosity and permeability of the basement foundation cracked concrete materials. This approach has been applied for simulating two-dimensional (2D) soil-gas and radon-entry into a house basement built on sand contaminated by uranium mill tailings (UMT) considering the presence of an aquifer with water-table, rainfall, evapotranspiration, atmospheric air pressure, and house under-pressurization.Sensitivity analysis of the model foundation parameters, performed at steady-state, showed that the numerical model predictions at transient conditions were in a good agreement with measurements of the radon-entry-rate through the basement foundation and radon concentration in the basement. The optimized parameters are physically sound and consistent with the observations and literature data.

Indoor Radon in Micro-geological Setting of an Indigenous Community in Canada: A Pilot Study for Hazard Identification.

Background: Radon is the second leading cause of lung cancer after smoking. In Canada, the health authorities have no access to comprehensive profile of the communities built over uranium-rich micro-geological settings. The present indoor radon monitoring guideline is unable to provide an accurate identification of health hazards due to discounting several parameters of housing characteristics. Objective: To explore indoor radon levels in a micro-geological setting known for high uranium in bedrock and to develop a theoretical model for a revised radon testing protocol.Methods: We surveyed a remote Inuit community in Labrador, located in the midst of uranium belt. We selected 25 houses by convenience sampling and placed electret-ion-chamber radon monitoring devices in the lowest levels of the house (basement/crawl space). The standard radon study questionnaire developed and used by Health Canada was used. Results: 7 (28%) houses had radon levels above the guideline value (range 249 to 574 Bq/ m3). Housing characteristics, such as floors, sump holes, ventilation, and heating systems were suspected for high indoor radon levels and health consequences. Conclusion: There is a possibility of the existence of high-risk community in a low-risk region. The regional and provincial health authorities would be benefited by consulting geologists to identify potentially high-risk communities across the country. Placing testing devices in the lowest levels provides more accurate assessment of indoor radon level. The proposed protocol, based on synchronized testing of radon (at the lowest level of houses and in rooms of normal occupancy) and thorough inspection of the houses will be a more effective lung cancer prevention strategy.

Radon exposure and tumors of the central nervous system

ObjectiveTo review the published evidence of links between radon exposure and central nervous system tumors through a systematic review of the scientific literature. MethodsWe performed a thorough bibliographic search in Medline (PubMed) and EMBASE. We combined MeSH (Medical Subject Heading) terms and free text. We developed a purpose-designed scale to assess the quality of the included manuscripts. ResultsWe have included 18 studies, 8 performed on miners, 3 on the general population and 7 on children, and the results have been structured using this classification. The results are inconclusive. An association between radon exposure and central nervous system tumors has been observed in some studies on miners, but not in others. The results observed in the general adult population and in children are also mixed, with some research evincing a statistically significant association and others showing no effect. ConclusionsWe cannot conclude that there is a relationship between radon exposure and central nervous system tumors. The available studies are extremely heterogeneous in terms of design and populations studied. Further research is needed in this topic, particularly in the general population residing in areas with high levels of radon.

Radon dynamics in a dwelling with high radon levels in a karst area

Abstract Year-long continuous radon monitoring was carried out (using Sarad Radon Scout devices) in a dwelling with high radon levels in the karst region of Slovenia. Two living rooms were selected: one on the ground floor with normal housework activities; and the second, on the first floor, closed and unattended. Meteorological data were also recorded. The following seasonal geometric means of radon activity concentration (kBq m −3 ) have been found: 6.28×/: 3.05 for spring, 1.25×/: 3.78 for summer, 5.17×/: 2.03 kBq m −3 for autumn and 9.83×/: 1.48 for winter on the ground floor; and 1.43×/: 3.71 for spring, 0.168×/: 2.49 for summer, 1.08×/: 2.39 for autumn and 2.08×/: 2.14 for winter on the first floor. Results are supported by additional radon measurements in other rooms; and in water the results indicate a strong radon source associated with an underground karst shaft.

Radon levels in Romanian caves: an occupational exposure survey.

A comprehensive radon survey has been carried out in seven caves located in the western half of Romania's most significant karst regions. Touristic and non-touristic caves were investigated with the aim to provide a reliable distribution of their radon levels and evaluate the occupational exposure and associated effective doses. Radon gas concentrations were measured with long-term diffusion-type detectors during two consecutive seasons (warm and cold). All investigated caves exceed the European Union reference level of radon gas at workplaces (300Bq/m3). The radon concentration in these caves ranges between 53 and 2866Bq/m3, reflecting particular cave topography, season-related cave ventilation, and complex tectonic and geological settings surrounding each location. Relatively homogeneous high radon levels occur in all investigated touristic caves and in Tăuşoare and Vântului along their main galleries. Except for Muierii, in all the other caves radon levels are higher during the warm season, compared to the cold one. This suggests that natural cave ventilation largely controls the underground accumulation of radon. The results reported here reveal that the occupational exposure in Urşilor, Vadu Crişului, Tăuşoare, Vântului, and Muierii caves needs to be carefully monitored. The effective doses to workers vary between an average of 0.25 and 4.39mSv/year depending on the measuring season. The highest values were recorded in show caves, ranging from 1.15 to 6.15mSv/year, well above the European recommended limit, thus posing a potential health hazard upon cave guides, cavers, and scientists.

Factors underlying persistently high radon levels in a house located in a karst limestone region of Ireland – lessons learned about remediation

Abstract The remediation of buildings with elevated radon concentrations is generally straightforward. However, in some cases a number of attempts may be needed to reduce concentrations to below the reference level and, occasionally, it may be impossible to reduce concentrations to below the reference level in a cost effective way. This paper details the work carried out between 2004 and 2012 to reduce radon concentrations in a house with initial radon concentrations of almost 1500 Bq/m3. Over this period, high radon levels were consistently recorded despite the introduction of various radon remedial measures. Remedial work was carried out on ten occasions with 29 radon tests carried out to measure the effect of this work. The paper describes the structure of the house and the karst geology that it is built on and the likely contribution of these factors to the difficulties encountered reducing concentrations. Ultimately, radon concentrations were reduced to about 450 Bq/m3 but no further reductions were considered practicable without substantial and costly renovation to the house. Nonetheless, the remedial work carried out to date has resulted in a significant reduction in the risk to the homeowner of developing lung cancer. This work has also added to the understanding of radon remediation techniques in Ireland, particularly for houses built on karst limestone.

Environmental assessment of radon levels in Cyprus

Purpose – Radon is responsible for approximately 50 per cent of public exposure to environmental radiation. The purpose of this paper is to quantitatively assess indoor radon levels in Cyprus. Design/methodology/approach – In total, 500 passive radon detectors were used to estimate radon levels in the areas of Nicosia (capital), Paphos, Nisou and Famagusta. A total of 240 different public and private buildings were randomly selected in the above districts and two passive radon detectors were placed inside each building. The detectors were collected on average, three months following placement. Findings – The average radon level from all passive detectors was 53.7 and 49.2 Bq/m3 after excluding the seven highest values. The two highest measurements were observed in Paphos, Tsada-Kili elementary school (429 Bq/m3) and Emba, Paphos district (410 Bq/m3), respectively. Differences were also seen in public buildings compared to private buildings (p=0.058). In addition, rural buildings had higher radon levels compared to urban buildings (p=0.001). Predictive multilevel regression models for logarithmic radon levels were employed and differences were seen on point estimates regarding building- and district-level radon measurements. Most of the random variability observed was due to building-level variation. Practical implications – Residents from different geographic areas in Cyprus are reassured about the safety of indoor radon levels in public and private buildings. Originality/value – The estimation of indoor radon levels was done by the optical microscopy technique using a specific mathematical formula. Observed radon levels do not raise concern regarding residents’ radon exposure in Cyprus. Paphos district and Nisou area may require further investigation.

Geographically weighted regression and geostatistical techniques to construct the geogenic radon potential map of the Lazio region: A methodological proposal for the European Atlas of Natural Radiation

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.

STUDY OF RADON FLUX FROM SOIL IN BUDHAKEDAR REGION USING SRM.

In the present study, the radon flux rate of the soil is measured using portable radon monitor (scintillation radon monitor) in the Budhakedar region of District Tehri, India. The study area falls along a fault zone named Main Central Thrust, which is relatively rich in radium-bearing minerals. Radon flux rate from the soil is one of the most important factors for the evaluation of environmental radon levels. The earlier studies in the Budhakedar region shows a high level of radon (>4000 Bq m-3). Hence, it is important to measure the radon flux rate. The aim of the present study is to calculate the average estimate of the surface radon flux rate as well as the effective mass exhalation rate. A positive correlation of 0.54 was found between radon flux rate and radon mass exhalation rate.

Experimental Measurements of VOC and Radon in Two Romanian Classrooms

The present study reports by experimental measurements the levels of volatile organic compounds (VOC) and radon concentrations in two high school classrooms. The difference between the two classrooms abbreviated as S7 and S8 is the presence of a mechanical ventilation system in one of them (S8). The topic is of high importance as the indoor air quality (IAQ) can affect the health and learning performance of the pupils. VOC and RADON have a substantial weight of IAQ and a study of theirs level can help us to better understand at what levels the children are exposed daily. The two mentioned classroom have suffered recently a massive renovation. The classroom with the ventilation system was mounted with variable flow of fresh air, while the other one relies only on natural ventilation by opening the windows. In S8 several test were done for different fresh air ventilation rates. The conclusions were that in the classroom S7 there were measured high levels of VOC and radon, higher than the maximum admissible which is a serious problem. On the other hand, in the classroom S8 for all the different air rates the values were very low, thus creating a healthy and comfortable environment for the learning process. In this article we raise again the problem of lack of a mechanical ventilation system in all Romanian schools. Due to thermal rehabilitation of the buildings the building is air sealed with negative impact on the introduced fresh air. Moreover, the high number of occupants in the classroom and the renovation of classroom have negative influence on all indoor pollutants levels. The only solution to these problems is a correct design of a school or to install other ways to mechanically introduce the fresh air.

Radon level in a Nigerian University Campus.

BackgroundGlobally, radon is a natural contaminant that affects indoor air quality. Several epidemiological studies have implicated high radon levels in the causality of lung cancer. The study therefore determined the environmental level of radon in selective offices in the Obafemi Awolowo University, Ile-Ife. The study employed a descriptive cross-sectional design. A Pro 3-series radon detector was used to determine the radon levels in randomly selected offices. The instrument was set-up in each office and after 48 h, reading was taken and recorded on a proforma data sheet. The structural characteristics of the offices were also assessed by observation.ResultsThe result revealed that the radon level obtained in the sampled offices ranged from 0.0 to 5.3 pCi/L (196 Bq/m3). The median concentration of radon obtained from sampled offices was 0.9 pCi/L. Almost all (95 %) of the offices had radon levels within the ‘permissible’ reference level recommended by World Health Organization. Radon levels also showed a statistically significant decline with height of office building with the mean concentration of radon in offices located on the basement, ground floor and first floor being 1.54 ± 1.32, 0.99 ± 0.56, 0.63 ± 0.41 pCi/L respectively, (F statistic 5.8, p < 0.001).ConclusionThe radon levels obtained in most assessed offices in Obafemi Awolowo University were found to be within the permissible reference levels. Mitigation measures should be put in place in the few offices above permissible levels.

Environmental impact of CO2, Rn, Hg degassing from the rupture zones produced by Wenchuan M s 8.0 earthquake in western Sichuan, China.

The concentrations and flux of CO2, (222)Radon (Rn), and gaseous elemental mercury (Hg) in soil gas were investigated based on the field measurements in June 2010 at ten sites along the seismic rupture zones produced by the May 12, 2008, Wenchuan M s 8.0 earthquake in order to assess the environmental impact of degassing of CO2, Rn and Hg. Soil gas concentrations of 344 sampling points were obtained. Seventy measurements of CO2, Rn and Hg flux by the static accumulation chamber method were performed. The results of risk assessment of CO2, Rn and Hg concentration in soil gas showed that (1) the concentration of CO2 in the epicenter of Wenchuan M s 8.0 earthquake and north end of seismic ruptures had low risk of asphyxia; (2) the concentrations of Rn in the north segment of seismic ruptures had high levels of radon, Maximum was up to level 4, according to Chinese code (GB 50325-2001); (3) the average geoaccumulation index I geo of soil Hg denoted the lack of soil contamination, and maximum values classified the soil gas as moderately to strongly polluted in the epicenter. The investigation of soil gas CO2, Rn and Hg degassing rate indicated that (1) the CO2 in soil gas was characterized by a mean [Formula: see text] of -20.4‰ and by a mean CO2 flux of 88.1gm(-2)day(-1), which were in the range of the typical values for biologic CO2 degassing. The maximum of soil CO2 flux reached values of 399gm(-2)day(-1) in the epicenter; (2) the soil Rn had higher exhalation in the north segment of seismic ruptures, the maximum reached value of 1976mBqm(-2)s(-1); (3) the soil Hg flux was lower, ranging from -2.5 to 18.7ngm(-2)h(-1) and increased from south to north. The mean flux over the all profiles was 4.2ngm(-2)h(-1). The total output of CO2 and Hg degassing estimated along seismic ruptures for a survey area of 18.17km(2) were approximately 0.57Mtyear(-1) and 688.19gyear(-1). It is recommended that land-use planners should incorporate soil gas and/or gas flux measurements in the environmental assessment of areas of possible risk. A survey of all houses along seismic ruptures is advised as structural measures to prevent the ingress of soil gases, including CO2 and Rn, were needed in some houses.

The health effects of radon and uranium on the population of Kazakhstan.

The radioactive contamination is a significant factor affecting the environment and human health. Radon and its decay products are the major contributors to human exposure from natural radiation sources. World Health Organization has identified the chronic residential exposure to radon and its decay products as the second cause of lung cancer after tobacco consumption and also as the main risk-factor in never smokers. The high levels of radon are observed in the North and East areas of Kazakhstan because of the natural radiation sources and the long-term and large-scale mining of uranium. The genotoxic effects of radon on population of Kazakhstan are poorly understood, in spite of the fact that many regions of the country contain the high levels of radon. Studies elucidating potential health risk among population exposed to radon and genotoxic effect of radon in Kazakhstan are very limited or they have never been addressed in some areas. In this review, we are presenting available data on the residential radon exposure of humans in uranium mining and milling areas in the North and East areas of Kazakhstan.

Radon and radioactivity at a town overlying Uranium ores in northern Greece

Extensive measurements of 222Rn in the town of Xanthi in N Greece show that the part of the town overlying granite deposits and the outcrop of a uranium ore has exceptionally high indoor radon levels, with monthly means up to 1500 Bq m−3. A large number of houses (40%) in this part of the town exhibit radon levels above 200 Bq m−3 while 11% of the houses had radon levels above 400 Bq m−3. Substantial interannual variability as well as the highest in Europe winter/summer ratios (up to 12) were observed in this part of the town, which consist of traditional stone masonry buildings of the late 19th-early 20th century. Measurements of 238U and 232Th content of building materials from these houses as well as radionuclide measurements in different floors show that the high levels of indoor radon measured in these buildings are not due to high radon emanation rates from the building materials themselves but rather due to high radon flux from the soil because of the underlying geology, high radon penetration rates into the buildings from underground due to the lack of solid concrete foundations in these buildings, or a combination thereof. From the meteorological variables studied, highest correlation with indoor 222Rn was found with temperature (r2 = 0.65). An indoor radon prognostic regression model using temperature, pressure and precipitation as input was developed, that reproduced indoor radon with r2 = 0.69. Hence, meteorology is the main driving factor of indoor radon, with temperature being the most important determinant. Preliminary flux measurements indicate that the soil-atmosphere 222Rn flux should be in the range 150–250 Bq m−2 h−1, which is in the upper 10% of flux values for Europe.