Radon Exposure Research Articles

A user’s guide to radon priority areas, examples from Ireland

Exposure to radon over time has significant detrimental effects on human health. Approximately 226,000 annual radon-related deaths have been reported from 66 countries (1). Many countries have a radon action plan, in order to reduce the harmful effects of radon exposure on the general public. Maps are routinely used to assist with mitigation strategies and delineate areas of priority regulation. Standard regulations in the European Union include the requirement for workplaces to test and the requirement to have reduction methods in newly built homes. Such laws are assigned systematically to areas that are understood to have high values of indoor radon. This article demonstrates that the boundaries of radon priority areas may vary, depending on the data set and methods used. We propose a table and a decision matrix to assist in choosing the most appropriate visual aid according to the purpose for which the map is to be used. We conclude that no single radon map is suitable to fit all objectives, and some maps are more suitable than others depending on the purpose.

The European Cancer Information System: exploring linkages between indoor radon concentrations and data on cancer burden

Exposure to radon over time has significant detrimental effects on human health. Approximately 226,000 annual radon-related deaths have been reported from 66 countries (1). Many countries have a radon action plan, in order to reduce the harmful effects of radon exposure on the general public. Maps are routinely used to assist with mitigation strategies and delineate areas of priority regulation. Standard regulations in the European Union include the requirement for workplaces to test and the requirement to have reduction methods in newly built homes. Such laws are assigned systematically to areas that are understood to have high values of indoor radon. This article demonstrates that the boundaries of radon priority areas may vary, depending on the data set and methods used. We propose a table and a decision matrix to assist in choosing the most appropriate visual aid according to the purpose for which the map is to be used. We conclude that no single radon map is suitable to fit all objectives, and some maps are more suitable than others depending on the purpose.

Abstract 025: Radon Exposure And Incident Stroke Risk In The Women’s Health Initiative

Background: Although the role of radon gas in lung carcinogenesis is well-known, relatively little is known about radon’s role in the pathogenesis or epidemiology of cerebrovascular disease. Methods: We therefore identified postmenopausal women without a history of stroke at the 1993-1998 screening visit of the Women’s Health Initiative Clinical Trials and Observational Study (WHI CT and OS). We linked their geocoded addresses to U.S. Environmental Protection Agency (EPA)-predicted, county-level, indoor, screening radon gas concentrations classified as follows: Zone 3 (<2 pCi/L), Zone 2 (2-4 pCi/L), and Zone 1 (>4 pCi/L). We identified incident strokes based on physician-reviewed, classified, and adjudicated medical records. We measured time from screening to the earliest stroke or censoring date (02/28/20). We used Cox proportional hazards models to estimate radon-related risk of stroke on an attained-age scale as a hazard ratio (HR) and 95% confidence interval (CI), adjusting for WHI design, race/ethnicity, education, homemaker status, U.S. Census region, neighborhood socioeconomic status, smoking, alcohol intake, sodium intake (g/day), 2005 Healthy Eating Index, recreational physical activity (MET-hr/wk), body mass index (kg/m 2 ), systolic blood pressure (mm Hg), as well as history of diabetes, hypercholesterolemia, atrial fibrillation, and deep vein thrombosis/pulmonary embolism. Results: Among 158,906 women (mean, standard deviation [SD] age = 63.1 [7.2] years; 83% white; 9% black; 4% Hispanic; 4% other), we identified 6,979 incident strokes over a mean [SD] follow-up period of 9.3 [5.6] person-years, i.e. 3.41 strokes / 1,000 person-years. The proportion of women with incident stroke was 1.38%, 1.72%, and 1.30% in EPA Radon Zones 3, 2, and 1, respectively. Corresponding incidence rates by EPA Radon Zone were 3.33, 3.43 and 3.49 per 1,000 person-years. Relative to women in Zone 3, those in Zones 2 and 1 had higher adjusted risks of incident stroke: HR (95% CI) = 1.07 (1.00, 1.14) and 1.15 (1.07 , 1.24). Conclusion: Radon gas is a pervasive carcinogen that also may increase susceptibility to a societally burdensome form of cerebrovascular disease, thereby highlighting the potential value of targeted testing, radon-safe construction, and mitigation in stroke prevention.

Effect of Time Since Smoking Cessation on Lung Cancer Incidence: An Occupational Cohort With 27 Follow-Up Years.

BackgroundThis special cohort reveals the effect of smoking cessation in occupational miners exposed to radon and arsenic.MethodsA total of 9,134 tin miners with at least 10 years of underground radon and arsenic exposure were enrolled beginning in 1992 and followed for up to 27 years. Detailed smoking information was collected at baseline, and information on smoking status was consecutively collected from 1992 to 1996. The Cox proportional hazards model was used to explore the relationship between time since smoking cessation and lung cancer.ResultsA total of 1,324 lung cancer cases occurred in this cohort over 167,776 person-years of follow-up. Among populations exposed to radon and arsenic, miners after quitting smoking for 10 years or more had almost halved their lung cancer risk [adjusted hazard ratio (HR) = 0.55, 95% CI: 0.38–0.79], compared with current smokers. Among miners after quitting smoking for 5 years or more, lung cancer incidence approximately halved (HR = 0.52, 95% CI: 0.30–0.92) for squamous cell lung carcinoma, while it showed no significant decline for adenocarcinoma (HR = 0.79, 95% CI: 0.34–1.85).ConclusionSmoking cessation for 10 years or more halved lung cancer incidence among miners exposed to radon and arsenic, and the benefit was more pronounced among squamous cell lung carcinoma.

Estimation of the Radon Risk Under Different European Climates and Soil Textures.

Radon is a radioactive gas produced from the natural radioactive decay of uranium and is found in almost all rocks and soils. In confined places (e.g., dwellings, workplaces, caves, and underground mines), radon may accumulate and become a substantial health risk since it is considered the second most important cause of lung cancer in many developed countries. Radon risk assessment commonly considers either field or estimate values of the radon concentration and the gas permeability of soils. However, radon risk assessment from single measurement surveys to radon potential largescale mapping is strongly sensitive to the soil texture variability and climate changes, and particularly, to the soil water content dynamic and its effect on soil gas permeability. In this paper, the gas permeability of soils, and thus, the estimation of radon risk, is studied considering the effect of three different climates following the Köppen classification and four soil textures on soil water content dynamics. This investigation considers the CLIGEN weather simulator to elaborate 100-year length climatic series; Rosseta 3 pedotransfer function to calculate soil hydraulics parameters, and the HYDRUS-1D software to model the dynamics of water content in the soil. Results reveal that climate strongly affects gas permeability of soils and they must be considered as an additional factor during the evaluation of radon exposure risk. The impact of climate and texture defines the soil water content dynamic. Coarse soils show smaller gas permeability variations and then radon risk, in this case, is less affected by the climate type. However, in clay soils, the effect of climate and the differences in soil water content derive in gas permeability variations between 100 and 1,000 times through an annual cycle. As a result, it may cross the boundary between two radon risk categories. Results deeply confirm that both climate and texture should be compulsory considered when calculating the radon exposure risk and in the definition of new strategies for the elaboration of more reliable geogenic radon potential largescale maps.

Radon Improves Clinical Response in an Animal Model of Rheumatoid Arthritis Accompanied by Increased Numbers of Peripheral Blood B Cells and Interleukin-5 Concentration.

Radon treatment is used as an established therapy option in chronic painful inflammatory diseases. While analgesic effects are well described, little is known about the underlying molecular effects. Among the suspected mechanisms are modulations of the anti-oxidative and the immune system. Therefore, we aimed for the first time to examine the beneficial effects of radon exposure on clinical outcome as well as the underlying mechanisms by utilizing a holistic approach in a controlled environment of a radon chamber with an animal model: K/BxN serum-induced arthritic mice as well as isolated cells were exposed to sham or radon irradiation. The effects on the anti-oxidative and the immune system were analyzed by flow-cytometry, qPCR or ELISA. We found a significantly improved clinical disease progression score in the mice, alongside significant increase of peripheral blood B cells and IL-5. No significant alterations were visible in the anti-oxidative system or regarding cell death. We conclude that neither cell death nor anti-oxidative systems are responsible for the beneficial effects of radon exposure in our preclinical model. Rather, radon slightly affects the immune system. However, more research is still needed in order to fully understand radon-mediated effects and to carry out reasonable risk-benefit considerations.

The Role of Mitochondrial miRNAs in the Development of Radon-Induced Lung Cancer.

MicroRNAs are short, non-coding RNA molecules regulating gene expression by inhibiting the translation of messenger RNA (mRNA) or leading to degradation. The miRNAs are encoded in the nuclear genome and exported to the cytosol. However, miRNAs have been found in mitochondria and are probably derived from mitochondrial DNA. These miRNAs are able to directly regulate mitochondrial genes and mitochondrial activity. Mitochondrial dysfunction is the cause of many diseases, including cancer. In this review, we consider the role of mitochondrial miRNAs in the pathogenesis of lung cancer with particular reference to radon exposure.

Radiation exposure due to 222Rn, 220Rn and their progenies in three metropolises in China and Japan with different air quality levels

Radiation exposure due to radon contributes most of the ionizing radiation exposure to people among natural radiation sources. This research measured the 222Rn, 220Rn by the RADUET and their progeny concentrations by the improved deposition based 222Rn and 220Rn progeny monitor, and the contribution of outdoor PM2.5 concentrations to indoors by a modified steady-state mass balance model in Beijing, Changchun, China and Aomori, Japan. Based on these results, we preliminarily explored the relevance between the city level outdoor PM2.5 exposure and indoor 222Rn, 220Rn inhalation exposure in these three metropolises with different air quality levels. The average equilibrium equivalent radon concentration (EERC) and equilibirum equivalent thoron concentration (EETC) indoor were 17.2 and 1.1 Bq m−3 in Beijing, 19.4 and 1.3 Bq m−3 in Changchun, and 10.8 and 0.9 Bq m−3 in Aomori, respectively. The indoor EERC and EETC in Beijing showed 1.4 and 2.2 times as high as that measured in 2006. The indoor radiation dose due to inhalation presented in a descending order as Changchun, Beijing and Aomori, which were in accordance with their outdoor 222Rn concentrations. The indoor radiation doses due to 220Rn contributed 30% of the total dose in the three cities, indicating that 220Rn cannot be neglected when evaluating indoor radiation dose. It should be noted that, the indoor PM2.5 concentrations of outdoor origin presented strong correlation (r = 0.772) with indoor EETC and moderate correlation (r = 0.663) with indoor EERC, indicating that the PM2.5 of outdoor origin can break the concentration balance of the indoor PM2.5, then affect the indoor 222Rn and 220Rn behaviors, and further affect the inhalation exposure of radon.

Increased Radon Exposure From Thawing of Permafrost Due To Climate Change

AbstractRadon is a natural radioactive gas accounting for approximately one in 10 lung cancer deaths, with substantially higher death rates in sub‐Arctic communities. Radon transport is significantly reduced in permafrost, but permafrost is now thawing due to climate change. The effect of permafrost thawing on domestic radon exposure is unknown. Here we present results from radon transport modeling through soil, permafrost, and model buildings either with basements or built on piles. We find that permafrost acts as an effective radon barrier, reducing radiation exposure to a tenth of the background level while producing a ten‐fold increase in the radon activity behind the barrier. When we model thawing of the permafrost barrier, we find no increase in radon to the background level for buildings on piles. However, for buildings with basements, the radon increases to over one hundred times its initial value and can remain above the 200 Bq/m3 threshold for up to 7 years depending on the depth of the permafrost and the speed of thawing. When thawing speed is taken into account, radiations remain higher than the threshold for all scenarios where 40% thawing occurs within 15 years. This new information suggests that a significant sub‐Arctic population could be exposed to radon levels dangerous to health as a result of climate change thawing of permafrost, with implications for health provision, building codes, and ventilation advice.

Seasonal Effect of Radon Exposure on Fractional Exhaled Nitric Oxide

Fractional exhaled nitric oxide (FeNO) measures airway inflammation, with higher levels associated with asthma exacerbations and lung function decline. Radon, an omnipresent radioactive gas, may have a role in obstructive lung disease outside its known carcinogenicity. We hypothesized that radon exposure would be associated with increased FeNO levels in inner-city children with asthma.

Evaluation of indoor radon levels in Staff offices of Umm Al Qura University, Saudi Arabia

Radiation is a natural part of the environment that people interact continuously, and radon is one of the most important sources because of its abundance and mobility. Due to gas form, radon can reach and accumulate in living places easily. Inhalation of radon and its progenies is an important risk factor for health hazards. Accurate measurement of radon levels is quite essential for the dose evaluation of radon exposure in buildings. In this present work, radon concentration was measured indoor 30 office in the College of applied Sciences/Umm Al-Qura University. Radon was measured with a portable Radon counter (Rad 7 detector, Durridge-USA), which was placed on the middle of office at a height of about 0.8 m. 222Rn gas levels were registered in Bq/m3. The measured concentration of radon in the air of office ranged from 14.2 ± 5.68 Bq/m3 to 23.9 ±7.52 Bq/m3 with a mean of 18.96 ± 8.3 Bq/m3, while that of the progeny of radon varied from 0.00164 to 0.00266 WLM Y-1 (average: 0.00211). The mean indoor concentration of radon was considerably less than the lower levels prescribed by EEC 400 Bq/m3, ICRP 200–600 Bq/m3, NRPB 200 Bq/m3, EPA 148 Bq/m3, and WHO 100 Bq/m3. The mean annual effective dose calculated 0.012 mSv y−1, which is less than the UNSCEAR and WHO recommended global lower average dose value of 1 mSv/y. The hazard indices (PAEC, and CPPP) values were lower than the permissibility limit value.

Quantitative evaluation of radon, tobacco use and lung cancer association in an occupational cohort with 27 follow-up years

BackgroundOccupational radon cohorts provide important information about exposure at residential level, which are difficult to observe prospectively. However, evidence about radon-related lung cancer risks from initial exposure in childhood or interaction between radon and smoking is still limited. MethodsA total of 6017 tin miners with at least 10 years of underground radon exposure were enrolled beginning in 1992 and followed for up to 27 years. Lung cancer risks were estimated by modeling total and intensity of radon exposure. ResultsA total of 933 lung cancer cases occurred in this cohort over 89,092 person-years of follow up. Excess relative risk increased by 0.96% per cumulative working level month (WLM). A unique aspect of this population was the early age at first radon exposure for workers. Results showed that lung cancer risk from initial radon exposure in childhood (<13 years old) was greater than risk when first exposure occurred at later ages (13–17, 18–24, and ≥ 25 years old). Moreover, risk declined with years since last exposure and attained age, but increased with age at last exposure. Importantly, these patterns were stable after adjustment for tobacco use or arsenic exposure. For joint effects of radon and other agents, our results support sub-multiplicative as the most likely model for interaction between radon and tobacco use or arsenic exposure. ConclusionThis study highlights the possible importance of radon exposure in childhood in cancer etiology and suggests another potential strategy to mitigate the global lung cancer burden.

Residential radon and characteristics of chronic obstructive pulmonary disease

It is not known whether residential radon exposure may be linked to the development of chronic obstructive pulmonary disease (COPD) and/or have an influence on the functional characteristics or exacerbations of COPD. The aim of this study was therefore to ascertain whether there might be an association between residential radon concentrations and certain characteristics of COPD. We analyzed COPD cases drawn from a case–control study conducted in an area of high radon exposure. Data were collected on spirometric pulmonary function variables, hospital admissions, and smoking. Radon measurements were taken using alpha-track-type CR-39 detectors individually placed in patients’ homes. All statistical analyses were performed using the IBM SPSS v22 computer software program. The study included 189 COPD cases (79.4% men; median age 64 years). The median radon concentration was 157 Bq/m3. No differences were found between radon concentration and sex, age or severity of breathing obstruction as measured by FEV1%. It should be noted, however, that 48.1% of patients with FEV1% < 50 had radon concentrations below 100 Bq/m3, as compared to 35.6% with the same severity of obstruction who had over 300 Bq/m3. COPD cases with radon concentrations higher than > 600 Bq/m3 exhibited no different characteristics in lung function. Exposure to radon does not appear to have an influence on the clinical characteristics of smokers and ex-smokers with COPD. As exposure to residential radon increases, there is no trend towards a worsening of FEV1%. Further studies are thus needed to analyze this possible association in never-smokers with COPD.

Repeated radon exposure induced lung damage via oxidative stress-mediated mitophagy in human bronchial epithelial cells and mice

This study aimed to investigate the potential molecular mechanism underlying radon-induced lung damage. Our results showed that long-term radon exposure induced mitochondrial damage and redox imbalance in BEAS-2B cells and a time-dependent lung pathological injury in mice. The activation of Nrf-2 and its down-stream antioxidants, and the gene expression of the indicated markers at different stages of autophagy were found to be induced with the increasing of radon exposure time. Changes in the gene expression of PINK-1, Parkin, and p62 induced by radon showed differences in mechanisms of mitophagy activation and profiles of autophagic flux between BEAS-2B cells and mice. Our findings not only demonstrated that long-term radon exposure induced damages to bronchial epithelial cells and the mice lung through increasing oxidative stress, decreasing mitochondrial function and activating mitophagy with different profiles of autophagic flux, but also revealed Nrf-2 as a central regulator of mitochondrial homeostasis and lung damage.

Importance of radon assessment in indoor Environment-a review

Radon is odourless, colourless indoor air pollutant from the radiation source of uranium. The source of radon in indoor are walls, floor and ceiling. Importance of radon detection at buildings are rare as it cannot be suspected until faced with an health issues. Concentration of radon in indoor environment depends on various factors. Lund disorders are the most commonly reported issue with radon exposure. This paper concentrates on the sources, factors influencing the radon dispersion and the health issues rise up with high radon exposure.

Spatial modeling for radon concentrations in subway stations in Seoul, Korea.

This study examined the environmental and geological determinants of radon concentration in subway stations by applying a spatial statistical model to the integrated GIS database. The data were collected for 237 underground subway stations located inside the city of Seoul, South Korea and used for mapping to illustrate the spatial distribution of airborne radon exposure and analysis of potential contribution of station-specific and geological determinants. A Bayesian conditional autoregressive regression (CAR) model was developed to explain the radon concentrations, and the predicted radon surface was generated and visualized to identify hotspot regions where elevated radon exposure is likely to be present in underground settings. The findings include: (1) subway stations located within granite bedrock maintained relatively higher radon concentrations; (2) underground radon emanation is not only controlled by lithology and the associated uranium content of the rocks and soil, but also by structural factors which facilitate easy migration of radon from deeper parts of the earth's crust; (3) radon risks would be elevated if the underground facility is constructed too deep without any control measure; and (4) not only the foundation of an underground facility but also the nature of the soil and rocks in the vicinity helps determine whether or not dangerous levels of radon gas are likely to accumulate inside. This modeling effort is expected to provide guidelines regarding the identification of future station locations with a lower radon risk and the mandatory installation of adequate radon reduction systems for the underground space where people stay or commute for long periods of time.

Management of Psychiatric Disorders in Patients with Respiratory Diseases.

Management of Psychiatric Disorders in Patients with Respiratory Diseases.

Exposure Due to Indoor Radon in Bulgarian Schools

Indoor radon exposure is the largest contributor to population dose from natural sources. Radon as a natural radioactive gas could accumulate to harmful levels in buildings, such as homes and buildings with public access. In order to assess the exposure due to radon in school the results of indoor radon measurements in 55 state school buildings in 7 municipalities located in one district in southern Bulgaria are considered in this paper. The survey was carried out with passive CR-39 etched track detectors. Radon concentrations ranged from 17 to 868 Bq m-3, with a geometric mean of 117 Bq m-3 and a geometric standard deviation of 1.78. The findings revealed that in 30% of the measured buildings the radon concentration was higher than the national reference level of 300 Bq m-3. The statistically significant difference in indoor radon concentrations between municipalities (KW, р < 0.001) was obtained. The research was also focused on parameters affecting radon concentration levels such as type of room and floor location. The estimated annual effective dose of 0.39 to 1.07 mSv y-1, applying the ICRP and UNSCEAR methodology, was calculated for students. The results of the measurements were provided to the administrative authorities and measures were proposed to improve the air in school buildings with high radon levels.

Radiation Protection Effect of Polydatin on Radon Exposure Injury of Epithelial Cells and Miceradiation Protection Effect of Polydatin on Radon Exposure Injury of Epithelial Cells and Mice

Radiation Protection Effect of Polydatin on Radon Exposure Injury of Epithelial Cells and Miceradiation Protection Effect of Polydatin on Radon Exposure Injury of Epithelial Cells and Mice

Assessment of thoron contribution to indoor radon exposure in Canada

From 2007 to 2013, simultaneous radon (222Rn) and thoron (220Rn) measurements were conducted in a total of 3534 residential homes in 34 metropolitan areas covering 71% of the Canadian population. While radon levels were above the detector’s detection limit in almost all homes, thoron concentrations were measurable in only 1738 homes. When analysis was limited to homes where thoron concentrations exceeded the detection limit, a pooled analysis confirmed that thoron is log-normally distributed in the indoor environment, and the distribution was characterized by a population-weighted geometric mean of 13 Bq/m3 and a geometric standard deviation of 1.89. Thoron contribution to indoor radon dose varied widely, ranging from 1.3 to 32% geographically. This study indicated that on average, thoron contributes 4% of the radiation dose due to total indoor radon exposure (222Rn and 220Rn) in Canada.