Radon in Schools: A Brief Review of State Laws and Regulations in the United States

Short-Term vs. Long-Term: A Critical Review of Indoor Radon Measurement Techniques

Radon is a known carcinogen, and the accurate assessment of indoor levels is essential for effective mitigation strategies. While long-term testing provides the most reliable data, short-term testing (STT) offers a quicker and more cost-effective alternative. This review evaluated the accuracy of STT in predicting annual radon averages and compared testing strategies in Europe (where long-term measurements are common) and the United States (where STT is prevalent). Twenty (20) studies were systematically identified through searches in scientific databases and the grey literature, focusing on STT accuracy and radon management. This review revealed several factors that influence the accuracy of STT. Most studies recommended a minimum four-day test for initial screening, but accuracy varied with radon levels. For low levels (<75 Bq/m3), a one-week STT achieved high confidence (>95%) in predicting annual averages. However, accuracy decreased for moderate levels (approximately 50% success rate), necessitating confirmation with longer testing periods (3 months). High radon levels made STT unsuitable due to significant fluctuations. Seasonality also played a role, with winter months providing a more representative picture of annual radon averages. STT was found to be a useful method for screening low-risk areas with low radon concentrations. However, its limitations were evident in moderate- and high-level scenarios. While a minimum of four days was recommended, longer testing periods (3 months or more) were crucial for achieving reliable results, particularly in areas with potential for elevated radon exposure. This review suggests the need for further research to explore the possibility of harmonizing radon testing protocols between Europe and the United States.

Analysis of the cancer occurrence related to natural radioactivity in the Rio Grande do Norte State, Brazil

The state of Rio Grande do Norte, located in the Northeast region of Brazil, has areas of granites and pegmatites with minerals that have varying concentrations of uranium. Consequently, high concentrations of radon gas, a carcinogenic substance for humans, can occur. The present study aimed to assess the occurrence of cancer and its association with exposure to sources of natural radioactivity using geological and geophysical information in the aforementioned state. The spatial dependence of pulmonary, breast, stomach, leukemia, and skin cancer cases with the location of radioisotope sources were analyzed using geoprocessing tools. The geoprocessing analysis showed a differential pattern of uranium emission throughout the state, with the highest emission from areas with pegmatites outcrops. A spatial dependency of cancer cases was shown (Moran index: 0.43; p < 0.01). Moreover, a higher rate of natural radioactivity-cancer cases was associated with the high-intensity natural radioactivity areas: odds ratio:1.21 (95% CI 1.20; 1.23), following the same pattern when separately compared the different related types of cancer. These results highlight the importance of natural radioactivity as a public health problem in the Brazilian environmental scenario, confirming the need for further studies as the first toward understanding and implementing health management strategies mitigating the exposures, especially in areas of environmental risk.

Quantifying indoor radon levels and determinants in schools: A case study in the radon-prone area Galicia-Norte de Portugal Euroregion

Radon is a carcinogenic compound, and is particularly concerning in the education sector, where children and teachers may be exposed even longer than at home. Thus, this study intended to characterise radon in the indoor air of scholar environments in different provinces/districts of the Euroregion Galicia-Norte de Portugal. With a pioneering approach, this study evaluated the influence of specific factors/characteristics (location, type of management, construction material, season and floor within the building) and quantified their relative contribution to indoor radon levels. Radon was continuously monitored in 416 classrooms from school buildings located in urban and rural sites from different provinces/districts both in the regions of Galicia (A Coruña and Lugo provinces) and Portugal (Porto and Bragança districts), considering rooms for different age groups (from nursery schools to universities). Single and multivariate linear regression models were built considering the radon concentrations as the outcome variable and different room/building characteristics as predictor variables. Mean and median radon concentrations were 332 Bq·m^-3 and 181 Bq·m^-3, respectively. The radon concentrations observed are a public health concern, as almost 1/3 of the places monitored exceeded the reference limit value of the European legislation (300 Bq·m^-3). Moreover, around 50 % of the indoor levels measured could be attributed to room/building characteristics: the building's location and the main construction material, as well as the occupants' age group, the floor within the building and the school's type of management (public/private). This study concluded that radon testing is needed in all school buildings and classrooms without exceptions. Thus, public administrations are urged to dedicate funds for testing, mitigation and public dissemination initiatives in schools. A special protocol for radon sampling in school buildings should also be developed.

Patterns of indoor radon concentrations, radon-hazard potential, and radon testing on a small geographic scale in Utah

INTRODUCTION

Currently, there are no publicly-available estimates of indoor radon concentration at scales smaller than the county. Radon-hazard potential soil maps that reflect underlying geologic factors can be created at small geographic scale and linked to residential and census data. We determined the association between residential radon tests and high radon-hazard potential soil at the residential and block group levels using a large Utah-based dataset. We also identified characteristics of block groups with limited tests in the dataset.

METHODS

We geocoded a dataset of residential radon tests obtained from 2001 to 2017 by a statewide educational program. We linked each location to maps of radon-hazard potential soil, the Environmental Protection Agency's (EPA) county radon zones. We also calculated the number of tests conducted in each block group and linked block groups to demographic data from the 2020 United States census. Log-linear and logistic models identified the association between residential home test results and 1) radon-hazard potential soil of each residence, 2) percent of residences on high radon-hazard potential soils in block groups, and 3) EPA's radon zones. We compared demographic characteristics among block groups with ≥5 or <5 residential tests in our dataset.

RESULTS

Approximately 42% of homes in the dataset tested ≥4 pCi/L. We found significant positive associations for residential radon test results with 1) residential location on high radon-hazard potential soil and 2) block groups with >0% of residences on high radon-hazard potential soil. EPA radon zones were not associated with residential test results. Block groups with <5 tests had higher than the statewide median percentage of Hispanic residents (OR = 2.46, 95% CI = 1.89-3.21) and were located in rural counties.

DISCUSSION

Radon-hazard potential soil has a significant association with residential home radon tests. More efforts are needed to improve radon testing in block groups that are rural and have greater percentages of racial minorities.

Determination of the indoor radon concentration in schools of Tenerife (Canary Islands): a comparative study

A radon survey was carried out in 18 high schools located in Tenerife Island when anti-pandemic strategies were used to reduce COVID-19 dissemination during 2021. High schools were located in radon-prone areas previously identified by the Spanish Nuclear Safety Council. Our results showed that 12 high schools presented radon activities lower than 100 Bq/m³, 5 high schools presented values in the range 100-200 Bq/m³, and only 1 high school presented radon activity concentration higher than 200 Bq/m³. Such values are below the reference level (300 Bq/m³) recommended by the Spanish legislation in the Basics Document of Health Standards (section HS6) of the Technical Building Code and the European Union directive (2013/59/EURATOM). Assuming an indoor occupancy time of about 1620 h per year, the annual dose contribution due to indoor radon exposure ranged from 0.07 to 1.18 mSv/year. Comparing such result against previous values reported in the literature on the island of Tenerife, we conclude that during the pandemic situation the indoor radon concentration (median valued) was reduced from 130.9 (2007) to 73.5 (2021) Bq/m³. Finally, continuous indoor radon concentration measurements were obtained to study short-time fluctuations (intra-day changes) under different ventilation conditions.

Radon in Indoor Air: Towards Continuous Monitoring

Radon poses significant health risks. Thus, the continuous monitoring of radon concentrations in buildings’ indoor air is relevant, particularly in schools. Low-cost sensors devices are emerging as promising technologies, although their reliability is still unknown. Therefore, this is the first study aiming to evaluate the performance of low-cost sensors devices for short-term continuous radon monitoring in the indoor air of nursery and primary school buildings. Five classrooms of different age groups (infants, pre-schoolers and primary school children) were selected from one nursery and one primary school in Porto (Portugal). Radon indoor concentrations were continuously monitored using one reference instrument (Radim 5B) and three commercially available low-cost sensors devices (Airthings Wave and RandonEye: RD200 and RD200P2) for short-term sampling (2–4 consecutive days) in each studied classroom. Radon concentrations were in accordance with the typical profiles found in other studies (higher on weekends and non-occupancy periods than on occupancy). Both RadonEye low-cost sensors devices presented similar profiles with Radim 5B and good performance indices (R2 reaching 0.961), while the Airthings Wave behavior was quite different. These results seem to indicate that the RadonEye low-cost sensors devices studied can be used in short-term radon monitoring, being promising tools for actively reducing indoor radon concentrations.

Internet of Things (IoT) Technologies for Managing Indoor Radon Risk Exposure: Applications, Opportunities, and Future Challenges

Radon gas is a harmful pollutant with a well-documented adverse influence on public health. In poorly ventilated environments, that are often prone to significant radon levels, studies indicate a known relationship between human radon exposure and lung cancer. Recent technology advances, notably on the Internet of Things (IoT) ecosystem, allow the integration of sensors, computing, and communication capabilities into low-cost and small-scale devices that can be used for implementing specific cyber-physical systems (CPS) for online and real-time radon management. These technologies are crucial for improving the overall building indoor air quality (IAQ), contributing toward the so-called cognitive buildings, where human-based control is tending to decline, and building management systems (BMS) are focused on balancing critical factors, such as energy efficiency, human radon exposure management, and user experience, to achieve a more transparent and harmonious integration between technology and the built environment. This work surveys recent IoT technologies for indoor radon exposure management (monitoring, assessment and mitigation), and discusses its main challenges and opportunities, by focusing on methods, techniques, and technologies to answer the following questions: (i) What technologies have been recently in use for radon exposure management; (ii) how they operate; (iii) what type of radon detection mechanisms do they use; and (iv) what type of system architectures, components, and communication technologies have been used to assist the referred technologies. This contribution is relevant to pave the way for designing more intelligent and sustainable systems that rely on IoT and Information and Communications Technology (ICT), to achieve an optimal balance between these two critical factors: human radon exposure management and building energy efficiency.

Environmental/Occupational Exposure to Radon and Non-Pulmonary Neoplasm Risk: A Review of Epidemiologic Evidence

Although Radon (Rn) is a known agent for lung cancer, the link between Rn exposure and other non-pulmonary neoplasms remains unclear. The aim of this review is to investigate the role of Rn in the development of tumors other than lung cancer in both occupational and environmental exposure. Particularly, our attention has been focused on leukemia and tumors related to brain and central nervous system (CNS), skin, stomach, kidney, and breast. The epidemiologic literature has been systematically reviewed focusing on workers, general population, and pediatric population. A weak increase in leukemia risk due to Rn exposure was found, but bias and confounding factors cannot be ruled out. The results of studies conducted on stomach cancer are mixed, although with some prevalence for a positive association with Rn exposure. In the case of brain and CNS cancer and skin cancer, results are inconclusive, while no association was found for breast and kidney cancers. Overall, the available evidence does not support a conclusion that a causal association has been established between Rn exposure and the risk of other non-pulmonary neoplasms mainly due to the limited number and heterogeneity of existing studies. To confirm this result, a statistical analysis should be necessary, even if it is now not applicable for the few studies available.

Radon in Schools: A Review of Radon Testing Efforts in Canadian Schools

Radon, a known carcinogen, becomes a health risk when it accumulates inside buildings. Exposure is of particular concern for children, as their longer life expectancy increases their lifetime risk of developing cancer. In 2016, 5.5 million students were enrolled in Canadian elementary and secondary schools. With no national policy on radon testing in schools, children may be at risk from radon exposure while attending school and school-based programs. This study explored radon testing efforts in publicly funded Canadian schools and summarizes where testing programs have occurred. Radon testing in schools was identified through a systematic qualitative enquiry, surveying members from different levels of government (health and education) and other stakeholders (school boards, research experts, among others). Overall, this research found that approaches to radon testing varied considerably by province and region. Responsibility for radon testing in schools was often deferred between government, school boards, building managers and construction parties. Transparency around radon testing, including which schools had been tested and whether radon levels had been mitigated, also emerged as an issue. Radon testing of schools across Canada, including mitigation and clear communication strategies, needs to improve to ensure a healthy indoor environment for staff and students.

Associations Between School Characteristics and Classroom Radon Concentrations in Utah's Public Schools: A Project Completed by University Environmental Health Students

Radon (²²²Rn), a radioactive gas, is the second leading cause of lung cancer deaths in the U.S. Classroom radon concentrations in public schools in our target area had never been measured or had not been measured in many years. We had university students, primarily enrolled in environmental health courses, measure radon concentrations in 2289 classrooms in 66 of Utah’s public schools and identify school characteristics associated with classroom radon concentrations. The geometric mean (GM) classroom radon concentration was 31.39 (95% confidence interval (CI): 27.16, 36.28) Bq/m³ (GM: 0.85; 95% CI: 0.72, 0.98 pCi/L). Thirty-seven (2%) classrooms in 13 (20%) schools had radon concentrations at or above the U.S. Environmental Protection Agency’s (EPA) recommended action level of 148 Bq/m³ (4.0 pCi/L). Number of classrooms had a u-shaped association with classroom radon concentrations. The year the heating, ventilation, and air conditioning (HVAC) system was installed was inversely associated with having classroom radon concentrations at or above the EPA’s recommended action level. Number of classrooms and number of students had u-shaped associations with having classroom radon concentrations at or above the EPA’s recommended action level. Classroom radon concentrations decreased when schools’ HVAC systems were on. Replacing HVAC systems and turning/keeping them on may be effective radon mitigation strategies to prevent radon-associated lung cancer, especially for small and large schools.

INCORPORATING KENAF AND OIL PALM NANOCELLULOSE IN BUILDING MATERIALS FOR INDOOR RADON GAS EMANATION REDUCTION

This study aims to reduce radon gas emanations in the indoor environment by incorporating kenaf and oil palm nanocellulose that act as nano-fillers into building materials. Fabrication of composite brick was carried out according to the MS and ASTM standards. In this research, 40, 80, 120, 160 and 200 ml of nanocellulose were used to replace the usage of sand, stone and cement materials, respectively. Kenaf and oil palm nanocellulose were utilised to reduce the internal and surface porosity as well as to replace the radon resources (stone), which indirectly reduced radon gas emanation. Radon gas emanated from each composite brick was measured within 10 consecutive days in an airtight prototype Perspex room using Radon Monitor Sentinel 1030. A compression test was also carried out to investigate the physical strength of the fabricated composite bricks. The results showed that 40 ml of kenaf and oil palm nanocellulose was the optimum amount in reducing the radon concentration, where the radon readings were 1.4 and 0.93 pCi per l, respectively. Meanwhile, the brick with no nanocellulose exhibited the highest radon reading of 3.77 pCi per l. Moreover, the Young modulus for the composite brick of both kenaf and oil palm nanocellulose was 28.92 and 27.8 N per mm2 compared to the control brick, which was 27 N per mm2. The results proved that radon gas emanations were reduced by 62.86% for kenaf and 75.3% for oil palm by incorporating the organic nanocellulose, which has high potential towards a healthy indoor environment.

Effect of ventilation strategies and air purifiers on the children's exposure to airborne particles and gaseous pollutants in school gyms

Indoor school gyms are environments characterized by high concentrations of different airborne particulate and gaseous pollutants. In particular, like other naturally-ventilated school environments, in addition to indoor pollutants children can be exposed to sub-micron particles and gaseous pollutants emitted by outdoor sources and penetrating the building envelope; moreover, high concentrations of super-micron particles can be reached due to the resuspension phenomena related to the physical activity performed therein. The present paper aims to evaluate the effect of different ventilation methods (natural ventilation, manual airing) and the use of air purifiers in reducing the indoor concentrations of different airborne particles and gaseous pollutants in school gyms. To this end, an experimental campaign was performed in two naturally-ventilated school gyms in Barcelona (Spain) of different volumes and different distance to major urban roads. Indoor and outdoor measurements of particle number, black carbon and PM_1-10 concentrations were performed as well as indoor measurements of CO₂ and NO₂ concentrations. The study revealed that the use of air purifiers with windows kept closed (natural ventilation) can lead to a significant reduction in terms of indoor-to-outdoor concentration ratios. In the smaller gym (air changes per hour of the purifiers, ACH, equal to 9.2 h^-1) the I/O ratios were reduced by 93% and 95% in terms of particle number and PM_1-10, respectively; whereas in the larger school gym (ACH = 1.7 h^-1) the corresponding reductions were 70% and 84%. For manual airing scenarios, the effect of the air purifiers on outdoor-generated sub-micron particles is reduced; in particular, for low ACH values (i.e. ACH = 1.7 h^-1), the reduction is quite negligible (6%).

Exploring relevance, public perceptions, and business models for establishment of private well water quality monitoring service

Existing public policies mostly focus on public water systems, leaving aside the quality issues regarding private wells in small and rural locations. Establishment of affordable and accessible water quality monitoring services may ensure acceptable levels of all the parameters. This paper aims to explore (a) health risk because of chemical contaminants of private wells, (b) population perspective on well water quality and monitoring, and (c) to create a business model of a centralized water quality monitoring service. The results show potential problems with toxic levels of arsenic, barium, cadmium, chromium, lead, mercury, and selenium. About 5% of the province's population is at risk for potential exposure to contaminated private well water. The survey reinforces that the successful implementation of water testing laboratories for private wells is a shared responsibility between well owners and the government organizations, and almost three-fourths respondents were willing to share the cost up to certain limit. A business model including financial projections for a centralized water testing laboratory is presented. Drinking of unmonitored private well water is putting population health at risk. Either strong regulation with mandatory water testing or voluntary water testing with adequate government subsidy can ensure sustainable function of a centralized water testing laboratory.