Search Results (761)

In recent years, the demand for indoor radon and air quality monitors has increased while more affordable consumer-grade monitors have become available. The aim of our study was to assess the validity of the less expensive, non-calibrated, consumer-grade Lüft (SunRADON LLC, Melbourne, FL, USA) compared to the more expensive, annually and manufacturer calibrated, industrial-grade Model 1028 XP (SunRADON LLC, Melbourne, FL, USA). We collected data about 24 h moving averages of barometric pressure, carbon dioxide (CO₂), radon, relative humidity, temperature, and volatile organic compounds (VOC) for approximately 29 weeks in 2024 in each of six rooms in a school in Utah. The mean difference in the co-located Lüfts’ and Model 1028 XPs’ 24 h moving average radon was −0.05 pCi/L of air (95% confidence interval: −0.24, 0.14, p = 0.50) and the concordance correlation coefficient (CCC) was 0.92. The Lüfts’ and Model 1028 XPs’ 24 h moving averages were similar for barometric pressure (CCC: 0.87), but the Lüfts’ 24 h moving averages were lower than the Model 1028 XPs’ for CO₂, relative humidity, and VOC and higher for temperature. The Lüft provided valid measurements of 24 h moving averages for barometric pressure and radon, but not for CO₂, relative humidity, temperature, and VOC. Full article

Background: Residential radon exposure is a leading risk factor for lung cancer, and climate change may exacerbate this risk by increasing radon entry into homes. In North Carolina (NC), disparities in lung cancer outcomes and low radon awareness disproportionately affect racially and ethnically diverse and low-income populations. However, little is known about how use of conventional address-based sampling (ABS) compares with community-engaged recruitment strategies for enrolling historically underrepresented populations into such research. Community-engaged approaches are used to improve participation in environmental health research, yet few studies compare their effectiveness with traditional approaches in NC. This manuscript compares recruitment outcomes between ABS and community-engaged approaches within the CLOVER study to address this gap. Materials and Methods: The Climate Impact on Lung Cancer via Exposure to Radon (CLOVER) study is a cross-sectional study examining climate-impacted radon exposure and lung cancer risk in NC. Participants were recruited using either ABS through a commercial address database or targeted community-engaged approaches implemented through partnerships with community organizations and culturally responsive, in-person outreach events. After providing informed consent, participants completed a household survey and a 7-day home radon test. Recruitment outcomes—consent, survey completion, and radon test return—were stratified by race and ethnicity and compared across strategies. Results: Of 236 consented participants, community-engaged recruitment enrolled a higher proportion of Non-Hispanic (NH) Black, Hispanic/Latino, and American Indian participants than ABS (57.3% vs. 41.9%). Community-engaged recruitment also had a higher consent rate than ABS (10.2% vs. 1.3%). Of the 145 participants who completed the survey, ABS participants completed surveys at a higher rate than community-engaged participants (73.3% vs. 54.7%), while of the 86 who returned the radon test kits, community-engaged participants did so at twice the rate of ABS participants (44.7% vs. 22.1%). Conclusions: Community-engaged recruitment enrolled a more racially and ethnically diverse sample and achieved higher consent and return rates than ABS, though ABS participants completed surveys at a higher rate. These findings highlight the importance of community partnerships and in-person recruitment strategies to improve participation of historically underrepresented populations in environmental health research and support equitable approaches to radon mitigation and lung cancer prevention. Full article

Sinogram images represent projection-domain data acquired during digital breast tomosynthesis (DBT), preserving angular information prior to reconstruction. However, their low contrast and noise-related degradation limit their direct use in downstream tasks. This work proposes a budget-constrained hybrid biomimetic optimization framework for projection-domain contrast enhancement based on the integration of Particle Swarm Optimization (PSO) and the Nelder–Mead (NM) simplex method. The approach combines global exploration with local refinement under a fixed number of objective function evaluations (NFE), enabling fair and computationally efficient comparisons with standalone optimizers. Experiments were conducted on 222 labeled mammographic images (136 benign and 86 malignant), which were transformed into sinograms via the Radon transform. The proposed method achieves competitive performance in terms of PSNR, SSIM, and FSIM, while exhibiting faster convergence and reduced computational cost compared to several state-of-the-art swarm-based approaches. Additionally, the impact of the enhanced sinograms was evaluated through a downstream classification task using a Vision Transformer-based knowledge distillation scheme, demonstrating improved discrimination between benign and malignant cases. These results demonstrate that the proposed budget-constrained hybrid biomimetic strategy provides an effective and computationally efficient solution for contrast enhancement in projection-domain medical imaging. Full article

Soil-gas observations can retain a source-related response while remaining ambiguous with respect to source amplitude, source depth, transport state, water state, and measurement support. This study develops a reduced one-dimensional source–transport–observation analysis for gas-continuous unsaturated soils. Integral-normalized source kernels, a finite-volume solver, a raw scaled-coordinate Jacobian, common-threshold nuisance projection, and an auxiliary noise-scaled check are combined in a reproducible workflow. At a display tolerance of 0.05, the primary structural convention normalizes parameter columns over the complete 11-row observation universe before extracting observation subsets. Under this convention, a carbon dioxide (CO₂) surface-flux observation retains one projected amplitude direction; within-set normalization reduces that restricted result to zero. The CO₂ profile, ideal-state-constraint set, and full diagnostic set retain ranks of 1/2, 2/3, and 3/4, respectively, under both conventions. The noise-scaled calculation places one projected source response at or above the illustrative one-standard-deviation threshold within a numerical tolerance of 1 × 10⁻¹⁰. A published-data worked example shows why water and carbonate context are required before a gas-phase CO₂ deficit is interpreted as a source decrease. The result is a pre-field screening method, not a site-calibrated inversion. Full article

Hin Dad hot spring is a prominent natural geothermal facility in Thailand, widely frequented by domestic and international tourists seeking hydrotherapy. According to UNSCEAR, radon (²²²Rn), thoron (²²⁰Rn), and their short-lived decay products represent the primary sources of natural ionizing radiation exposure to humans. Geothermal waters inherently carry elevated levels of these radionuclides, potentially exposing visitors and facility staff to radiological hazards. This study evaluated ²²²Rn concentrations in water samples alongside ambient air concentrations of ²²²Rn, ²²⁰Rn, and their respective progeny within the Hin Dad hot spring area. The average ²²²Rn levels in water across six sampling sites ranged from 3 ± 1 to 24 ± 1 Bq L⁻¹, remaining well below the World Health Organization (WHO) screening level for ²²²Rn in water (100 Bq L⁻¹). Ambient air monitoring was conducted using both active and passive techniques. Active measurements via an AlphaGuard detector at three designated points yielded average ²²²Rn and ²²⁰Rn concentrations ranging from 12 to 41 Bq m⁻³ and 23 to 38 Bq m⁻³, respectively. As expected from the partitioning behavior of radon between water and air, atmospheric concentrations were markedly lower than the corresponding aqueous ²²²Rn concentrations. Furthermore, long-term passive monitoring over 103 days using RADUET detectors revealed maximum time-integrated average concentrations of 66 ± 1 Bq m⁻³ for ²²²Rn and 47 ± 4 Bq m⁻³ for ²²⁰Rn. All atmospheric concentrations complied with the reference levels established by both the WHO and the International Commission on Radiological Protection (ICRP) (100–300 Bq m⁻³); as this range is defined for indoor environments, it is applied here only as a conservative benchmark for the open and semi-outdoor monitoring stations. Regarding progeny exposure, the maximum Equilibrium Equivalent ²²²Rn Concentration (EERC) and Equilibrium Equivalent ²²⁰Rn Concentration (EETC) were determined to be 21.0 ± 2.5 Bq m⁻³ and 2.7 ± 0.3 Bq m⁻³, respectively. The measured concentrations and estimated doses indicate a low radiological concern under the conditions investigated, though the assessment is based on two seasonal sampling rounds and does not include personal dosimetry or wet-season monitoring. Full article

Radon-222, a decay product of the uranium-238 series, is the principal source of natural ionizing-radiation exposure in most indoor environments and an established cause of lung cancer. In New Mexico, uranium-bearing geology, a legacy of uranium mining and milling, and arid, variably constructed housing create elevated but poorly characterized geogenic radon potential. This evidence-informed narrative review examines radon protection in New Mexico by synthesizing the radiological basis of the hazard (uranium-series sources, radium-226 emanation, and soil–gas transport into buildings) with measurement, monitoring, and mapping evidence relevant to under-resourced regions. We emphasize that representative, high-resolution indoor radon measurements for the state are still lacking. We show that the central challenge is not only geologic potential but the uneven distribution of measurement, testing, and mitigation capacity across housing type, tenure, geography, and jurisdiction, including Tribal lands governed by consent-based data agreements. We evaluate monitoring and outreach interventions by evidence strength and outline a phased, standards-based program (statewide measurement and data systems, high-resolution mapping, school and rental testing, workforce development, and mitigation support) to convert radiological knowledge into measurable, equitable exposure reduction. New Mexico serves as a well-documented representative example; the synthesis is intended to inform other rural, Tribal, and under-resourced jurisdictions. Full article

Hybrid dynamical systems may exhibit Zeno behavior, where infinitely many discrete transitions occur in finite time, leading to a loss of well-posedness of trajectories beyond the accumulation point. This paper develops a measure-theoretic formulation of hybrid dynamics by representing discrete transitions through finite vector-valued Radon measures and recasting the system as a measure differential inclusion. Within this framework, we establish a closure result for extended hybrid solutions in the space of functions of bounded variation and derive an existence result under suitable approximation assumptions. We also prove consistency with classical hybrid trajectories in the absence of Zeno behavior and characterize the state at the Zeno time as the left limit of the hybrid evolution, together with any additional vector atom deliberately assigned at the accumulation time. The proposed formulation provides a natural basis for continuation beyond the accumulation point and allows Lyapunov-based stability properties to be formulated directly at the level of the measure-driven dynamics. A central feature of the approach is that infinitely many discrete transitions with finite total variation of the jump increments are encoded by a finite vector-valued atomic measure whose atoms may accumulate at the Zeno time. An additional vector atom at the Zeno time may be introduced as a lumped effective jump; however, such an atom should be understood as a modeling choice, not as an automatic consequence of the jump sequence. The results are illustrated on an event-triggered control system exhibiting Zeno accumulation. Full article

The long-term preservation of historical documents in archival environments is critically challenged by the accumulation of hazardous gases—formaldehyde (HCHO), benzene (C₆H₆), and radon (Rn)—which originate from collection materials and pose severe health risks to personnel. In this work, we systematically investigate, via first-principles theory, the potential of Au- and Ru-doped PtSe₂ monolayers as resistive-type gas sensors for the detection of these pollutants. Atomic-scale substitutional doping at the Se site is modeled to establish the doped PtSe₂ configurations, and the structural stability, electronic properties, adsorption behavior, charge transfer characteristics, and recovery kinetics of the doped systems are comprehensively evaluated and compared. Our findings, through comprehensive comparison, reveal that Ru-PtSe₂ outperforms its Au-doped counterpart across all key performance metrics, positioning it as a promising candidate for hazardous gas monitoring in archival environments. The key innovation of this work lies in the systematic comparative assessment of noble metal dopants on PtSe₂ monolayers, identifying Ru as a superior choice to Au and providing a theoretical foundation for designing high-performance, recyclable 2D material-based gas sensors tailored for cultural heritage preservation applications. Full article

European regulations require Member States to develop strategies for reducing radon exposure in buildings. Italy has adopted a national radon action plan aimed at defining strategies for reducing the long-term risks associated with indoor radon. Based on public data provided by the national radon database, a baseline scenario in Italy has been developed for key risk reduction actions, quantifying radon measurements in buildings, buildings above the reference level, and remedial actions in buildings. The results show that the buildings tested account for less than 1%, and only 9% of the buildings above the reference level have been remediated. This highlights the importance of continuing to measure radon levels in buildings and the need to step up remediation efforts. Using the available data, the current national situation is outlined using three key parameters, which can be easily updated and which are necessary to guide policymakers on measurement programmes and radon mitigation strategies required by national legislation. Based on the results, the municipalities with the most reliable data were ranked according to the necessary actions to be taken and the priorities for intervention. Updating the scenario over time will make it possible to compare the results achieved with the initial baseline in order to assess the effectiveness of the regulatory strategy at the national level. Full article

Residential radon is an invisible radioactive gas produced during the uranium-238 decay series and is an established cause of lung cancer. In Canada, recent national surveillance suggests that about one in five residential buildings may exceed the national radon guidelines, yet household testing remains uncommon. This narrative clinical review translates international and Canadian evidence into practical primary-care and hospital-to-community actions. Evidence was prioritized from carcinogen classifications, World Health Organization guidance, pooled residential case–control analyses, Canadian surveillance and guidance, and the peer-reviewed literature on mechanisms, histology, and risk communication. Radon-222 can enter buildings from soil gas; its short-lived progeny deposits in the respiratory tract and emits high-linear-energy-transfer alpha particles that can damage bronchial epithelial DNA. Because elevated levels cannot be reliably predicted from symptoms, smoking status, house age, or community maps, clinicians should use a simple workflow: ask about prior testing and lower-level occupancy; test with a long-term, approved device in the lowest occupied level; act by interpreting the result, advising mitigation, and directing patients to certified radon professionals when needed; document the exposure assessment, result, advice, referral, and retesting plan; and follow up after mitigation or major building changes. This review clarifies Canadian residential and workplace guidance, contrasts global reference-level approaches, and distinguishes radon prevention from lung cancer screening. No individual patient information or human-subject data are reported. Full article

Background: Radon in drinking water is a potential source of ionizing radiation exposure, yet long-term monitoring data from active tectonic regions remain limited. This study investigated ²²²Rn activity concentrations in drinking-water wells along the Sultandağı Fault (Afyonkarahisar, Türkiye) and assessed age-dependent radiological risks. Methods: ²²²Rn concentrations were measured at two-week intervals in 15 drinking-water wells between June 2021 and June 2022 using a WG-1001 water–gas separation system and an AB-5R radiation monitor. Annual effective dose (AED) and excess lifetime cancer risk (ELCR) were calculated for infants, children, and adults. Results: ²²²Rn concentrations ranged from 0.05 to 26.64 Bq L⁻¹, with a mean of 6.12 ± 2.79 Bq L⁻¹. Only one well exceeded the USEPA guideline level (11.1 Bq L⁻¹), whereas all measurements remained below the WHO reference level (100 Bq L⁻¹). Seasonal mean concentrations varied between 5.48 ± 2.53 and 7.08 ± 3.32 Bq L⁻¹. Mean AED values were 35.94, 13.17, and 15.63 μSv y⁻¹ for infants, children, and adults, respectively. Corresponding ELCR values were 1.26 × 10⁻⁴, 0.46 × 10⁻⁴, and 0.55 × 10⁻⁴. Conclusions: The results indicate generally low radiological risk from radon in drinking water within the study area, although elevated values were observed in some wells. Higher age-specific dose and risk estimates were obtained for infants. These findings provide long-term data on groundwater ²²²Rn variability in an active fault zone and support regional radiological risk assessment. Full article

Due to the advanced plans for the development of nuclear power plants in Poland, those who are to live around nuclear facilities may have unjustified doubts about their own radiation safety. Moreover, when future power plant workers will be potentially exposed to low, cumulative doses of ionizing radiation, it seems important to develop cytogenetic methods for showing the actual genotoxic effects of environmental or occupational nuclear influences. The method of analyzing the frequency of chromosomal type aberrations in peripheral blood lymphocytes remains one of the most significant possibilities in achieving this goal. Three techniques are used to monitor aberration frequency, i.e., most commonly, Giemsa staining (FPG), FISH, or M-FISH. The types of aberrations determined by Giemsa-staining preparation will be described in detail, and issues with the nomenclature of these aberrations will be discussed. To effectively explore small changes in aberration yields, studies of aberration rates in non-exposed populations are needed. Such a dataset has been generated at the Institute of Nuclear Chemistry and Technology (INCT), Warsaw, Poland. This database would allow for the assessment of the genotoxic impact of planned nuclear facilities, the impact of radon in areas within its increased concentration, or the impact of such a working environment on, for example, medical workers working with radiation. Full article

Although radon measurements have been carried out in most countries for several decades, a rigorous methodology for assessing the reliability (as well as the effectiveness) of indoor radon testing between short-term and long-term measurements has not yet been established at either the national or international level. National regulators, lacking scientific justification, arbitrarily set the duration of indoor radon testing (from a few minutes to several months) preferring long-term measurements simply because it “seems more reliable”. To solve this fundamental regulation problem, an original (innovative) methodology is proposed based on the algorithms of the previously published Rational Method for indoor radon testing, which ensures 95% decision-making reliability within modern metrological concepts. A comparison of the reliability (and effectiveness) between short-term and long-term measurements can be made by taking into account the radon situation at both national and global levels. The obtained dependence of the mean (among 26 countries) percentage of definite (reliable) decisions vs. the duration of measurements indicates: (i) the greater effectiveness of using short-term measurements compared to long-term ones, as well as (ii) the excessive focus of national and international regulators only on instrumental uncertainty within QA/QC to the detriment of temporal (key) uncertainty in decision-making. Key conclusion: The established practice of radon regulation on both global and national levels contains a number of underlying myths, and therefore clearly needs to be rethought and updated within a rational (scientific) strategy. A vital necessity are specific experimental (field) studies to verify (clarify) the national values of the temporal (key) uncertainty of indoor radon (and thoron EEC), as well as the creation of simple and effective (inexpensive but reliable) IoT tools for large-scale measurements of indoor radon through the involvement (and at the expense) of the population. Full article

This study presents the development and application of a continuous monitoring system to operate in hybrid mode for the atmospheric and oceanic environments. The developed system integrates a smart version of the underwater in situ sensor named KATERINA to a stationary platform in order to operate as a real-time communication tool. The data are transferred using a mobile telephony network and the power is generated for all modules by a solar panel. The system is applied for a period of around six months in different seasons to detect and identify gradients of environmental radioactivity in the atmosphere. The system observed gamma-ray emitters during dry and wet periods, exhibiting enhanced radon progenies during wet periods as identified in the acquired spectra. Moreover, the gross gamma-ray intensity depends on the radon progenies and is used as a tracer to interpret rainfall events in a qualitative manner. The background gamma-ray spectra during dry periods for different seasons are also discussed in terms of seasonality. The correlation of gamma-ray intensity rate with the rainfall rate is also studied for the wet periods, providing a R² value of around 75%. Full article

This study presents a combined analysis of radon and meteorological time series acquired over several years in a building regularly occupied by workers and occasionally by visitors. The building is founded directly on basaltic tuff in an area characterized by elevated radon levels. A multilevel monitoring system with high spatial and temporal resolution was deployed, consisting of 14 low-cost detectors measuring radon and indoor meteorological parameters; an outdoor weather station was employed for environmental and soil monitoring, and a RAD8 instrument was used to identify the main radon entry points. The monitoring system allowed us to characterize, on daily and seasonal timescales, the variability of radon concentration throughout the building and its dependence on meteorological and anthropogenic factors. Cluster analysis combined with a principal component analysis revealed three distinct meteorological regimes (warm, cold, stormy). Indoor radon concentration centroids in the cold and stormy regimes were associated with up to about 3.9 kBq/m³ at RDP2exp, over an order of magnitude above the EU reference level of 300 Bq/m³, while warm, dry conditions yielded significantly lower levels. Horizontal radon diffusion times ranged from 30 to 90 min, and vertical diffusion times ranged from 90 to 180 min across floors. A 24 h exposure risk assessment shows that occupancy during working hours (08:00–18:00) coincides with the daily radon minimum, but baseline concentrations remain above 300 Bq/m³ even during these periods, necessitating mitigation strategies. Full article