High Radon Levels Research Articles

Contemporary technologies in research to control and reduce the health risk of radon exposure

Ionizing radiation of terrestrial origin is a topic of global interest and the main objective is the study of the medical-biological effects on health. The academic community is in continuous research on the development of methods for detecting them. One of the most important elements participating in the creation of the natural background of ionizing radiation, with a major impact on health is radon. It cannot be perceived by the human senses as it is an odorless, colorless, and tasteless gas. Radon inhaled into the alveoli of the lungs disrupts the main cellular processes, the translation and transcription of DNA and RNA molecules, thus occurring a series of mutations in the genetic apparatus. Exposure to high levels of radon is the second leading cause of lung cancer after tobacco use.Determining the concentration of radon in the air of residential homes, public buildings and workplaces is a priority action for the development and implementation of the action plan in the context of the objectives of EURATOM Directive 59/2013.

Research on Best Solution for Improving Indoor Air Quality and Reducing Energy Consumption in a High-Risk Radon Dwelling from Romania.

The purpose of this article is the assessment of energy efficiency and indoor air quality for a single-family house located in Cluj-Napoca County, Romania. The studied house is meant to be an energy-efficient building with thermal insulation, low U-value windows, and a high efficiency boiler. Increasing the energy efficiency of the house leads to lower indoor air quality, due to lack of natural ventilation. As the experimental campaign regarding indoor air quality revealed, there is a need to find a balance between energy consumption and the quality of the indoor air. To achieve superior indoor air quality, the proposed mitigation systems (decentralized mechanical ventilation with heat recovery combined with a minimally invasive active sub-slab depressurization) have been installed to reduce the high radon level in the dwelling, achieving an energy reduction loss of up to 86%, compared to the traditional natural ventilation of the house. The sub-slab depressurization system was installed in the room with the highest radon level, while the local ventilation system with heat recovery has been installed in the exterior walls of the house. The results have shown significant improvement in the level of radon decreasing the average concentration from 425 to 70 Bq/m3, respectively the carbon dioxide average of the measurements being around 760 ppm. The thermal comfort improves significantly also, by stabilizing the indoor temperature at 21 °C, without any important fluctuations. The installation of this system has led to higher indoor air quality, with low energy costs and significant energy savings compared to conventional ventilation (by opening windows).

Variability of indoor radon concentration in UK homes

This study investigated the variability of indoor radon concentrations in 518 100 homes in the UK. The statistical analysis included measurements in 395 720 homes with downstairs living rooms and upstairs bedrooms. The radon concentration in these bedrooms was found to be on average 63% of the living room value. The analysis of 122 380 homes with living rooms and bedrooms situated on the same floor found that there is a small difference in radon concentration of 9% between the two rooms. The results showed that the ratios of the living room to bedroom radon concentrations were approximately lognormally distributed. The geometric mean of the ratio was found to be 1.6 for rooms situated on different storeys and 1.1 for rooms situated on the same floor. It was found that house characteristics and energy efficiency measures affect the distribution of radon within homes. Detached houses and those with suspended floors had higher radon levels in their upstairs bedroom, 66.7% and 76.9% of the downstairs living room values, respectively. For homes built between 1993 and 2007, the bedroom to living room ratio increased from 58.8% to 76.9% due to the increased airtightness and improved energy performance of the modern buildings. Homes with installed wall and loft insulation had much higher bedroom to living room ratio (76.9%) than those without energy efficiency measures (52.6%).

The level of free-circulating mtDNA in patients with radon-induced lung cancer

ObjectiveAccording to the World Health Organization, radon is the second leading cause of lung cancer after smoking. Cell free circulating mitochondrial DNA (cf mtDNA) have been used not only as a biomarker of carcinogenesis but also as a biomarker of exposure to radiation, but nothing is known about changes in the level of cf mtDNA following radon exposure. Therefore, the purpose of this study was to estimate the cf mtDNA copy number as a biomarker of the response to radon exposure in lung cancer pathogenesis. Methods207 subjects were examined including 41 radon-exposed lung cancer patients, 40 lung cancer patients without radon exposure and 126 healthy controls exposed/not exposed to high level of radon. Total cell free circulating DNA from blood samples was extracted and used to detect cell free circulating mitochondrial DNA copy number by quantitative real-time polymerase chain reaction (qRT-PCR). ResultsOur data indicate that the level of cf mtDNA in the radon-induced lung cancer patients was significantly higher than that of the other study participants. There was a significant difference in the level of cf mtDNA in the blood plasma of healthy volunteers exposed and not exposed to high doses of radon. Moreover, in healthy volunteers living in areas with high radon levels, the mtDNA copy number was higher than that in patients with lung cancer who were not exposed to high doses of radon. ConclusionOur study provides evidence for a possible role of cf mtDNA as a promising biomarker of lung cancer induced by exposure to high dose of radon.

Use of Theory-Driven Report Back to Promote Lung Cancer Risk Reduction.

Report back is active sharing of research findings with participants to prompt behavior change. Research on theory-driven report back for environmental risk reduction is limited. The study aim is to evaluate the impact of a stage-tailored report back process with participants who had high home radon and/or air nicotine levels. An observational one-group pre-post design was used, with data collection at 3, 9, and 15 months post intervention. Participants from the parent study (N = 515) were randomized to the treatment or control group and this sample included all 87 treatment participants who: (1) had elevated radon and/or air nicotine at baseline; and (2) received stage-tailored report back of their values. Short-term test kits measured radon; passive airborne nicotine samplers assessed secondhand smoke (SHS) exposure. Stage of action was categorized as: (1) ‘Unaware’, (2) ‘Unengaged’, (3) ‘Deciding’, (4) ‘Action’, and (5) ‘Maintenance’. Interventions were provided for free, such as in-person radon and SHS test kits and a brief telephonic problem-solving consultation. Stage of action for radon mitigation and smoke-free policy increased from baseline to 3 months and remained stable between 3 and 9 months. Stage of action for radon was higher at 15 months than baseline. Among those with high baseline radon, observed radon decreased by 15 months (p < 0.001). Tailored report back of contaminant values reduced radon exposure and changed the health behavior necessary to remediate radon and SHS exposure.

Regional cost effectiveness analyses for increasing radon protection strategies in housing in Canada

The incremental cost effectiveness ratios for implementing a recent recommendation to install a more radon resistant foundation barrier were modelled for new and existing housing in 2016, for each province and territory in Canada. Cost-utility analyses were conducted, in which the health benefit of an intervention was quantified in quality-adjusted life years, to help guide policymakers considering increasing investment in radon reduction in housing to reduce the associated lung cancer burden shouldered by the health care system. Lung cancer morbidity was modelled using a lifetable analysis that incorporated lung cancer incidence and survival time for localized, regional, and distant stages of diagnoses for both non-small cell and small cell lung cancer. The model accounted for surgical or advanced lung cancer treatment costs avoided, and average health care costs incurred for radon-attributable lung cancer cases prevented by the intervention. The incremental implementation of radon interventions in the housing stock was modelled over a lifetime horizon, and a discount rate of 1.5% was adopted. This radon intervention in new housing was cost effective in all but one region, ranging from $18,075/QALY (15,704; 20,178) for the Yukon to $58,454/QALY (52,045; 65,795) for British Columbia. A sequential analysis was conducted to compare intervention in existing housing for mitigation thresholds of 200 and 100 Bq/m3. This intervention in existing housing was cost effective at a mitigation threshold of 200 Bq/m3 in regions with higher radon levels, ranging from $33,247/QALY (27,699; 39,377) for the Yukon to $61,960/QALY (46,932; 113,737) for Newfoundland, and more cost effective at a threshold of 200 than 100 Bq/m3. More lung cancer deaths can be prevented by intervention in new housing than in existing housing; it was estimated that the proposed intervention in new housing would prevent a mean of 446 (416; 477) lung cancer cases annually. The cost effectiveness of increased radon resistance in foundation barriers in housing varied widely, and would support adopting this intervention in new housing across Canada and in existing housing in higher radon regions. This study provides further evidence that the most cost effective way of responding to the geographically variable radon burden is by implementing specific regional radon reduction policies.

Occupational Radon Assessment in Underground Storage Facilities in Saudi Arabia.

An occupational radon assessment was conducted at five underground storage facilities in the Kingdom of Saudi Arabia to evaluate the radon concentration and determine if remedial action is required to ameliorate conditions and ensure compliance with international guidance on acceptable radon levels in working environments. The assessment was carried out in four operational areas in the underground storage facilities routinely occupied or visited by workers. Initial radon concentrations were obtained using 293 passive CR-39 Nuclear Track Detector (NTD) radon dosimeters installed in the four operational areas for all the underground storage facilities. The detectors were left in place for 12 mo. As some of the radon measurements exceeded the International Atomic Energy Agency reference level of 1,000 Bq m-3 for radon in workplaces, a follow-up assessment was conducted using a real-time monitoring device in locations where high radon levels were observed. The measured radon concentrations in the four operational areas in three of the five underground storage facilities were below the reference level, and in the remaining two storage facilities, low ventilation rates in one operational area were identified as the principal cause of elevated radon concentrations. Notwithstanding, the potential radiation dose from radon exposure was determined to be well below the International Commission on Radiation Protection reference annual dose level of 10 mSv in all five underground storage facilities. Radon exposure to workers in all the underground storage facilities was found to be within the reference dose level for workplaces and does not pose an acute health risk.

Study of Abnormal Seasonal Variations in the Radon Exhalation Rate in a Fault Zone

Strong seasonal variations in the radon exhalation rate from the soil surface were revealed during a two-year monitoring cycle in a fault zone on a slope of Mount Beshtau in the Caucasus Mineral Water Resort area, Russia. The variations are characterized by very high radon levels in summer and low levels in winter. In the warm season (from late April to early October), the radon exhalation rate values ranged from 4.5 to 23.8 Bq m–2 s–1. During the cold period (from November to March), the radon levels decreased to 0.04–0.17 Bq m–2 s–1. A strong correlation was found between the radon exhalation and atmospheric air temperature (the Pearson correlation coefficient is 0.8). The simulation results show that seasonal fluctuations in the radon exhalation rate are caused by an inversion of the convective radon transport direction in the fractured zones of the rock massif. In summer, the convective flow of radon is directed from the rock massif to atmosphere, whereas this flow in winter comes from the atmosphere to rock massif. The rate of convective transport varies from 5 to 28 m day–1 during the warm season and from –2 to –4 m day–1 during the cold one. Seasonal radon anomalies in fault zones are most probably caused by thermally induced convective air flows in the highly permeable rock zone due to the temperature difference between the rock air and atmospheric air. Seasonal radon anomalies should be taken into account both when mapping radon risk and when using radon as a tracer of gas transport in geochemical and geophysical research.

Spatial and temporal variations in indoor radon concentrations in Pennsylvania, USA from 1988 to 2018

Indoor radon poses one of the most significant environmental threats to public health as it is the second leading cause of lung cancer in the United States. Developing a more thorough understanding of the factors that affect radon concentrations is key for developing risk maps, identifying where testing should be a priority, and education about indoor radon exposure. The objectives of this study are to investigate seasonal and annual variation of indoor radon concentrations in Pennsylvania, USA from 1988 to 2018, to explore the hotspot areas for high indoor radon concentrations, and to analyze the association with various factors such as weather conditions, housing types, and floor levels. Based on a total of 1,808,294 radon tests conducted from 1988 to 2018, we found that 61% of the area (by zip codes), 557,869 tests conducted in the basement and 49,141 tests conducted on the ground floor in homes in Pennsylvania had higher radon levels than the U.S. EPA action level concentration of 148 Bq/m3 (equivalent to 4 pCi/L). Winter and fall had significantly higher indoor radon concentrations than summer and spring. Case studies conducted in Pittsburgh, Philadelphia, and Harrisburg showed that there was no significant correlation of daily temperature, precipitation, or relative humidity with indoor radon concentration on the day a radon test occurred.

Detecting concealed fire sources in coalfield fires: An application study

A majority of coal mines in China are susceptible to fires, especially those affected by concealed fire sources in coalfield fire areas. Hence, to mitigate this problem, the efficient and precise detection of high-temperature anomalous areas is significant and needed, which mainly involves determining the range and depth of concealed fire sources. In this paper, the strengths and weaknesses of each detection method (e.g., remote sensing, electromagnetic radiation, magnetic detection, geological radar detection, resistivity detection, transient electromagnetic, excitation potential method, gas analysis, radon levels detection, infrared images) were investigated, analyzed, evaluated and then compared. Furthermore, after taking their respective practicality and effectiveness into account, an integrated methodology was proposed that uses radon levels, infrared imaging techniques, and drilling methods to detect and verify high-temperature anomalous areas in a coalfield. We carried out the detection in the Ningxia autonomous region. Our testing results revealed that radon levels show positive correspondence with the temperature of potential fire sources. That is to say, higher radon levels usually have higher temperature signal for detection. Accordingly, high-temperature anomalous areas in coalfield fire areas can be distinguished and delineated successfully by their radon levels and verified by infrared imaging techniques and drilling methods.

Quality assessment of indoor radon measurements. Results of the international radon in-field intercomparison study

The article presents the results of the international radon in-field intercomparison study for passive radon measurement devices. The tests were organized by the environmental agency of the administrative region of Piemonte (Ivrea, Italy). Coverage of participants was 49 laboratories from 15 countries (Italy, Hungary, France, Great Britain, Lithuania, Russia, Sweden, Spain, Bulgaria, Argentina, Australia, Finland, Ireland, Greece and Slovenia). The certified radon passive devices included SSNTDs and electret detectors. SSNTDs are mostly represented by PADC plastic (CR-39) and nitrocellulose film (LR-115-2) detectors. Radon measuring devices were tested in long-term exposure modes at low and high radon levels (tests 1 and 2) and short-term exposure mode at the simultaneous presence of radon and thoron in the atmosphere (test 3). The intercomparison study was carried out in real conditions of operated buildings with different climatic conditions. The main purpose of this study was to evaluate the quality (accuracy and reliability) of the radon measurements under situations similar to the ones in which devices are normally exposed. In comparison with electrets, solid-state track detectors showed to have generally better reproducibility. For the electrets, the most «comfortable» radon measurement conditions were prolonged exposure at high radon levels. There was no significant fading effect of SSNTD at long-term exposure observed. The paper presents the results of the quality assessment of REI-4 passive device based on LR-115-2 widely used for radon monitoring studies in the Russian Federation.

Radiometric evaluation of indoor radon levels with influence of building characteristics in residential homes from southwestern Nigeria.

Indoor radon (222Rn) measurements were carried out using solid state nuclear track detectors (SSNTD) in some dwellings from southwestern Nigeria. This was aimed at statistically assessing influence of building characteristics on the measured radon and estimating excess lifetime cancer risks (ELCR). The measured radon concentrations followed lognormal distribution and were significantly influenced by some building properties. The arithmetic mean (1.60mSv) of annual effective doses (AEDs) due to indoor radon was observed to be higher than the world average level (1.15mSv) but less than lower limit (3mSv) of International Commission on Radiological Protection (ICRP). The evaluated excess lifetime cancer risk ranged from 1.5 to 28.1 (MPy)-1 with an average value of 6.3 (MPy)-1, indicating that after exposure to indoor radon for 70years, 6 people in every 1000 are likely to suffer the risk of developing lung cancer. Adequate ventilation systems were recommended for houses with high level of radon to avoid unnecessary exposure to radon. However, the investigated data would form important component of the database required to set up guidelines and policy of controlling radon at home.

Radon and thoron exhalation rate, emanation factor and radioactivity risks of building materials of the Iberian Peninsula.

Radon (222Rn) and thoron (220Rn) are radioactive gases emanating from geological materials. Inhalation of these gases is closely related to an increase in the probability of lung cancer if the levels are high. The majority of studies focus on radon, and the thoron is normally ignored because of its short half-life (55.6 s). However, thoron decay products can also cause a significant increase in dose. In buildings with high radon levels, the main mechanism for entry of radon is pressure-driven flow of soil gas through cracks in the floor. Both radon and thoron can also be released from building materials to the indoor atmosphere. In this work, we study the radon and thoron exhalation and emanation properties of an extended variety of common building materials manufactured in the Iberian Peninsula (Portugal and Spain) but exported and used in all countries of the world. Radon and thoron emission from samples collected in the closed chamber was measured by an active method that uses a continuous radon/thoron monitor. The correlations between exhalation rates of these gases and their parent nuclide exhalation (radium/thorium) concentrations were examined. Finally, indoor radon and thoron and the annual effective dose were calculated from radon/thoron concentrations in the closed chamber. Zircon is the material with the highest concentration values of 226Ra and 232Th and the exhalation and emanation rates. Also in the case of zircon and some granites, the annual effective dose was higher than the annual exposure limit for the general public of 1 mSv y−1, recommended by the European regulations.

PREHISTORY OF THE CZECH RADON PROGRAM.

In the Czech Republic, the program managing high radon levels in dwellings has existed for nearly 30years. Although the recent history of radiation protection from naturally radioactive gas is quite well known, prior radon management is less understood. This article describes the history of natural radioactivity and its management from the Middle Ages, showing that Czech countries have a much longer and abundant history related to natural radioactivity.

A comparison of consumer-grade electronic radon monitors

Radon is a radioactive gas which is naturally occurring in soil and can accumulate to concentrated levels inside homes and buildings. Exposure to elevated levels of radon leads to an increased risk of developing lung cancer. In recent years there has been a rise in the popularity of consumer-grade electronic radon monitors. The monitors are appealing to homeowners due to the ease of use and the ability to keep track of radon levels during the process of conducting a radon test. However, there is currently no independent process to evaluate the relative performance of these monitors against known levels of radon. In this study, three sample units of six different models representing three different manufacturers of consumer-grade electronic radon monitors were exposed to three different levels of radon in a controlled environment to evaluate their precision and accuracy. Two separate tests were conducted at the Canadian guideline level to accommodate for ‘indoor winter’ and ‘summer’ conditions. The purpose of the study was to compare the performance of the different consumer-grade electronic radon monitors and determine which factors should be considered when using these monitors to inform mitigation decisions. The monitors had a range of uncertainty from 2%–15% with a range of precision from 1%–24%. The monitors performed better at higher radon levels than at levels near the Canadian guideline level of 200 Bq m−3, and slightly better during ‘summer’ conditions than during ‘indoor winter’ conditions. While the monitors provide homeowners with a very specific number indicating their radon level, it was noted that this number should be considered with respect to a ‘confidence ratio’ or ‘range’ which could be done through a publicly available online tool which could provide the radon level range for a given radon level and device grade.

A model comparison of diffusion-controlled radon exhalation from solid and cavity walls with application to high background radiation areas.

Radon exhaled from building material surfaces is an important source of indoor radon. Yangjiang, located in the southern part of mainland China, is well-known as a high background radiation area (HBRA). Rather, high levels of radon and thoron concentration have been observed in adobe and brick houses. Reducing the indoor radon concentration remains an important issue in the high background radiation areas of China and the world. Generally, the walls of Chinese dwellings are solid. In this paper, a simple one-dimensional model for predicting the radon diffusion in a cavity wall is proposed, and an analysis formula describing the radon exhalation rate from cavity wall surfaces is presented. The influence on the radon exhalation rate due to leakage through structural joints and building material cracks is analyzed. The simulation results indicate that the radon exhalation rate from a cavity wall surface is far lower than that from a solid wall. The structure of cavity walls themselves is therefore useful as a mechanism for reducing the indoor radon in high background radiation areas across the world.

Creating a safe and dry basement by overcoming the conflict between waterproofing and gas proofing

Basement living and working is frequent in the UK, with barely a week going past without mention in the press of planning applications for a ‘superbasement’ or ‘billionaire’s bunker’. All basements are at risk of containing high levels of radon, the naturally occurring radioactive gas, regardless of their geographic location. Since 1999, designers and contractors have been steered towards the use of internally fitted cavity drain membrane systems for basement waterproofing. Such systems are based on air gap technology, however, and are not appropriate for gas proofing, rather they may inadvertently increase radon concentrations in the property. This paper explores the conflict between best practice waterproofing and effective gas proofing, and a process that was developed to solve the dilemma, along with case studies of successful installations.

Radon kinetics in a natural indoor radon chamber

An unusual 180 m3 storage room in the basement of a two-story laboratory building is unventilated, and separated from occupiable rooms by double steel doors. The space completely borders on soil through the concrete floor and two of its concrete walls. The room also contains a separate inner chamber with 1 m thick concrete walls designed to damp vibrations in the room above it. The space boasts a relatively high radon level, 1083 Bq m−3, which varies with local outdoor environmental conditions. Measurements were made of radon concentrations at various locations and heights within the facility. More than a year of continuous radon concentration data corresponding to a single location are also available, along with measurements of indoor and outdoor pressure, temperature, and humidity. Data were also collected with as many as five fans placed in different locations and cycled on for variable time periods. First order linear kinetic models were created to explain the observed approaches to steady state due to changing conditions and wash-out resulting from intentional ventilation. Results demonstrate a good fit between changes in the radon concentration level and the developed compartmental models. However, no significant differences were observed between radon concentration at different locations or heights in the chamber.

An examination of radon awareness, risk communication, and radon risk reduction in a Hispanic community

Purpose: Radiation risk communication is a critical component of radiation protection and the public’s understanding of radiation risks and benefits. Risk communication becomes even more complicated when considering cultural and language differences. In the US, many diverse communities face risk communication challenges. We obtained radon testing data to evaluate patterns of radon testing in Allentown, the third largest city in Pennsylvania. Radon exposure is the second leading cause of lung cancer after smoking and is associated with over 21,000 lung cancer deaths in the US annually. It is estimated that 1 in every 15 homes in the US has elevated radon levels above the recommended action level set by the US Environmental Protection Agency. Allentown has some of the highest reported levels of indoor radon in the country, yet only a small portion of the population has tested their homes. This is true particularly among self-identified Hispanics, who make up nearly half of the city’s population. This study seeks to (1) characterize the difference in testing rates between self-identified Hispanics and non-Hispanics in Allentown, (2) quantify the level of radon awareness and knowledge, (3) identify potential obstacles to radon testing among the Allentown population that self-identifies as Hispanic, and (4) determine whether more effective risk communication is needed.Method: Radon test results in Allentown were analyzed to better understand the nature of radon testing. To evaluate radon awareness and knowledge, a cross-sectional study was conducted using a face-to-face survey. This data was informative in assessing testing and mitigation practices, ethnicity, income level, age, education level, homeowner status, zip code and primary language.Results: Ethnicity was an independent predictor of radon awareness and knowledge. Statistically significant differences were found between the number of self-identified Hispanics (39%) and non-Hispanics (84%) who indicated that they had ever heard of radon; 13% of Hispanics and 49% of non-Hispanics knew that they lived in an area with typically high radon levels. There was a statistically significant association between self-reported ethnicity and radon testing with non-Hispanics (43%) more likely to test their homes for radon than Hispanics (32%).Conclusion: Individual and community understanding of the risks of exposure to radiation sources such as radon is dependent upon communication that informs and spurs appropriate action. This study demonstrates the need for culturally appropriate radon risk communication strategies targeted to a Hispanic population. Successful communication will raise awareness and knowledge that can lead to better public health protection.

A new radon prediction approach for an assessment of radiological potential in drinking water

Inhaled radon from groundwater used for domestic purposes is one of the sources of natural radioactivity into indoor air. Due to uranium-bearing minerals occurrences, hydrogeochemical conditions, tectonic structures, and hydraulic circuits, the radon pathway from rocks to groundwater is quite unpredictable. High radon potential from bedrocks is not always associated with high radon levels in groundwater. Besides, inhaled radon from domestic use may also increase the exposure toindoor radon levels. This innovative methodology using hydrogeochemical conditions and groundwater flow transport was used for radon predictions in the underground to ensure safe drinking water ingestion and inhalation. This innovative radon prediction methodology is based on classic hydrogeochemical analyses (Eh-pH, Piper, Schöeller and Gibb's diagrams) and multivariate statistical analyses (Principal Component Analysis and Pearson's correlation). High dissolution of major ions does not imply high radon mobilization from rocks to groundwater. The travel time was estimated to developed a flow transport of contaminated groundwater. Radiological results show that of the 25 sampled springs, five of them contained radon concentrations above the Portuguese imposed limit (222Rn = 500 Bq·L−1), and 16 of them with values above the WHO recommended limit (222Rn = 100 Bq·L−1).Overall, this new approach of radon prediction showed that uranium enrichment in rocks at ideal hydrochemical conditions and emanation coefficient, and shallow circuits, are responsible for radon increasing in drinking water. The proposed approach allow to predict the areas with high radon potential groundwaters, being a tool to be used by water planners and policy makers for corrective and preventive measures in shallow groundwater flows. To safeguard clean water within the predefined deadline of Sustainable Development Goals (2030) and to ensure human health in compliance with WHO guidelines for safe drinking water, should be established priority water protection policies to reduced radon in this contaminated springs (n = 16).