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According to a NIH study, Lung cancer among individuals who have never smoked is more prevalent in women and occurs at an earlier age than in smokers. The rise in lung cancer rates among female non-smokers might be linked to radon inhalation and should be further investigated. Our theory is based on the differences in radon exposure between males and females, which can be attributed to the variations in time spent indoors versus outdoors. Over the past few years, the smoking rates have shown a steady decline in the United States and other developed countries. This decrease in smoking prevalence has led to a new shift in the primary risk factors associated with lung cancer. Although tobacco smoke historically served as the primary cause of lung cancer, the reduction in smoking rates has allowed other risk factors, such as radon exposure, to come to the forefront. Given that women in certain countries, on average, might spend more time indoors compared to men, they are potentially exposed to higher levels of radon. This increased exposure could explain the rising rates of lung cancer among female non-smokers. The theory is still in its nascent stages and requires further research and validation. However, if proven correct, it could significantly alter our understanding of lung cancer risk factors and lead to new prevention. It is therefore crucial to expedite the review and publication of this theory, given its potential implications for public health.

The paper presents comments, remarks and opinions on the material presented in the publication “Radon regulation crisis in Russia: scale of the problem and proposals for remediation” by Tsapalov A., Miklyaev P., Petrova T., Kuvshinnikov S., published in the Russian peer-reviewed journal “ANRI” (“Radiation measurement equipment and news”), 2024, No. 1.

This study assessed the activity concentrations of gross alpha, gross beta, Radon and heavy metals in groundwater sources from illegal mining areas in Doguwa Local Government, Kano State, Nigeria. Water samples from five distinct mining areas were analyzed for gross alpha and beta radioactivity using a portable single-channel gas-free proportional detector (MPC2000B-DP) via ISO9696 and ISO9697 methods, Radon levels with a Rad7 (DURRIDGE) detector, and heavy metals with atomic absorption spectroscopy. Gross alpha concentrations ranged from 0.0000238 to 0.00013 Bq/L, averaging 0.00008158 Bq/L, a value below the WHO limit of 0.5 Bq/L. Gross beta concentrations ranged from 0.536 to 2.78 Bq/L, averaging 1.7056 Bq/L, exceeding the WHO limit of 1.0 Bq/L. Radon levels varied from 0.12 to 1.7 Bq/L, averaging 1.102 Bq/L, below the WHO limit of 11.1 Bq/L. Annual effective doses from gross alpha ingestion were 4.10918E-05, 4.16874E-06, and 8.33748E-06 mSv/year for adults, infants, and children, respectively. Radon exposure doses were 1.61E-13 and 8.04E-14 mSv/year for adults and children, respectively, below the 0.1 mSv/year limit. However, beta radiation doses exceeded the 0.1 mSv/year limit, with values of 0.85911072, 0.21477768, and 0.42955536 mSv/year for adults, infants, and children, respectively. The average concentrations of heavy metals were 0.00058 mg/L for Cd, 0.012 mg/L for Cr, 0.00628 mg/L for Fe, 0.0046 mg/L for Mn, 0.09534 mg/L for Ni, 0.01214 mg/L for Pb, and 0.00582 mg/L for Zn. Children exhibited elevated cancer risks from heavy metal ingestion 0.004865 and dermal exposure 0.000069, with hazard quotient values of 0.740205 and 0.004882, respectively. The hazard index and lifetime cancer risk for children were 0.004882, exceeding USEPA recommended values. While gross alpha and radon levels were within safety limits, beta radiation levels and heavy metal hazard quotients exceeded maximum contamination levels, highlighting significant health risks, including DNA damage and increased cancer risks.

Citizen science projects have garnered attention for their potential to engage the public in scientific research and address societal challenges. However, assessing their impacts has often been overlooked or approached with overly simplistic methods. Aiming to fill this gap, this article draws on existing literature to propose an evaluation framework to critically examine how citizen science initiatives influence science, society and the participants themselves. This framework is tested on four citizen sciences projects in the field of radon research through content analysis of project reports and deductive analysis of 11 semi-structured interviews with citizen scientists and coordinators of the projects. The study demonstrates the feasibility of measuring the impacts of citizen science projects across scientific, participant, societal and researcher dimensions at the outcome level but also process evaluation at the process level. Our findings indicate that the proposed framework provides a comprehensive evaluation tool for citizen science projects, particularly in the field of radon research, and underscore the significant potential for improving participants' knowledge on radon and risk mitigation strategies, as well as positive shifts in behaviour towards testing and mitigation and influencing public health policies. [ABSTRACT FROM AUTHOR]

The key natural cause of irradiation in humans is the air. People spend most of their time at home, so home is likely a main source of natural radionuclide exposure in the air, especially radon gas. It is the second cause of lung cancer after smoking. This study aims to evaluate Radon‐222 gas (222Rn) concentrations in the houses (indoor dwellings) of the Al‐Hussainya district of the Karbala Governorate, Iraq. Also, some radiological parameters such as AED (annual effective dose), PAEC (potential alpha energy concentration), EP (exposure to radon progeny), and CPPP (lung cancer cases per year per million people) were calculated. 222Rn concentrations were determined using closed and open dosimeters with CN‐85 detector (thickness of 12 μm). The range and average of 222Rn concentrations were from 21.791 Bq/m3 to 43.376 Bq/m3 and 32.3381 Bq/m3 in open dosimeters, respectively. While in closed dosimeters, the range of 222Rn concentrations and average values were from 19.324 Bq/m3 to 37.286 Bq/m3 and 26.6462 Bq/m3, respectively. The average values of AED, PAEC, EP, and CPPP due to radon by open dosimeters were 0.083 mSv/y, 0.358 mWL, 14.759 mWLMY−1, and 1.503, respectively, while the average values of AED, PAEC, EP, and CPPP due to radon by closed dosimeters were 0.063 mSv/y, 0.270 mWL, 11.134 mWLMY−1, and 1.134, respectively. According to WHO, EPA, and ICRP, the values of radon concentrations were within the range of what was allowed internationally. Also, the results of the radiological parameters due to radon gas for the study of the houses of the Al‐Hussainya district of the Karbala Governorate, Iraq, were low and did not constitute a health hazard. [ABSTRACT FROM AUTHOR]

Understanding radon‐prone areas is vital to prevent radon‐related health problems, enhance public safety, and ensure adherence to regulations aimed at minimizing radon exposure. We conducted a comprehensive review of cross‐sectional studies reporting on residential radon exposure in Iran. Our review encompassed studies published until February 13, 2022. Out of the 966 articles initially identified, 37 studies were included in our analysis, which measured indoor radon levels in a total of 3480 residential buildings in Iran. Notably, the highest residential radon levels (Bq.m−3) were found in Mazandaran province, with the most hazardous recorded levels in Talesh Mahalleh (3235), followed by Ramsar (1299). Conversely, Tehran, the capital city of Iran, had the lowest recorded levels of residential radon, at 11.0 Bq.m−3. Remarkably, indoor radon concentration exceeded both the reference levels recommended by the World Health Organization (WHO) and the standard levels set by the U.S. Environmental Protection Agency (US.EPA), with approximately 51% and 26%, respectively. The mean effective doses received by Iranian residents were 5.0 mSv.y−1 (0.3–81.7). Moreover, the mean excess lifetime cancer risk (ELCR) associated with indoor radon exposure was determined to be two per 1000 people. The annual incidence of lung cancer cases (LCCs) per million people attributed to indoor radon exposure in Iranian residential buildings ranged from 5.00E − 06 to 1.47E − 03. The included studies addressed a wide range of variables affecting radon levels, but they did not cover all factors comprehensively. These factors encompass the meteorological parameters, geological characteristics, building construction materials, building type, window type, occupancy information, and ventilation rates in enclosed spaces. The potential health risks associated with indoor radon exposure necessitate the implementation of effective control measures. These should include raising public awareness, revising construction regulations, enhancing ventilation systems, identifying high‐risk areas, and conducting more comprehensive studies to better understand the factors that influence radon concentration. [ABSTRACT FROM AUTHOR]

Ship wake detection stands as a pivotal task in marine environment monitoring. The main challenge in ship wake detection is to improve detection accuracy and mitigate false alarms. To address this challenge, a novel procedure for ship wake detection in a single SAR image is proposed in this study. Initially, an entropy distance similarity criterion is designed to measure nonlocal image patch similarity. Based on the proposed criterion, a low-rank and sparse decomposition method is modified using nonlocal similar patch matrix construction to separate the sparse wake. Subsequently, a field-of-experts (FOE) model is introduced to generate a series of multi-view wake feature maps, which are fused to construct an enhanced feature map. The sparse wake is further enhanced in the Radon domain with the enhanced feature map. The experimental results demonstrate the effectiveness of the proposed method on real SAR ship wake images. [ABSTRACT FROM AUTHOR]

In this study we evaluate the uranium and radon concentrations in groundwater from the Province of Safi. The samples were collected from 58 wells across five communes and analyzed using the LR-115 type II detector. Results indicate that uranium concentrations ranged from the Limit of Detection (LLD) to 3.73 µg/l, with a mean of 0.72 µg/l, well below the World Health Organization’s safe limit of 30 µg/l. Radon levels varied from LLD to 2.39 Bq/l, with an average of 0.60 Bq/l, also below the United States Environmental Protection Agency’s limit of 11 Bq/l. The estimated total annual effective dose due to uranium and radon ranged from 3.47 to 18.84 µSv/y, with an average of 7.54 µSv/y, which is significantly lower than the European Commission’s recommended limit of 100 µSv/y. This investigation represents the first study of uranium and radon levels in groundwater in the Province of Safi, providing valuable data for future research and public health. [ABSTRACT FROM AUTHOR]

This study presents the results of a pilot survey utilizing an innovative DVD-based method to measure outdoor radon and thoron levels. Twenty-six discriminative radon/thoron detectors were deployed across four different territorial zones in Bulgaria. Positioned 1 m above the ground, these detectors were left in place for several months. Notably, the dataset reveals significant variability in measurements, even over short distances, with thoron exhibiting greater variability than radon. Radon levels ranged from 7 ± 1 to 34 ± 3 Bq m−3 (average: 21 Bq m−3), while thoron levels ranged from 13 ± 5 to 307 ± 54 Bq m−3 (average: 170 Bq m−3). A weak but statistically significant correlation (correlation coefficient: 0.559) was observed between radon and thoron levels, which improved significantly when averaged across the four zones. These findings underscore the importance of measuring both radon and thoron in outdoor surveys. High thoron levels can significantly bias radon measurements, particularly when radon concentrations are substantially lower than those of thoron. If further studies confirm the good correlation between area averages, the observed correlation between area-average values could be used to correct average radon levels in large areas (e.g., radon priority areas) for thoron interference when thoron data are missing from the analyzed radon dataset. [ABSTRACT FROM AUTHOR]

Radon concentrations in the tourist part of the Cango cave were measured using 25 strategically placed electret ion chambers. Airflow rates were also measured and found to be less than 1 m/s throughout the cave. An IDW interpolated radon concentration overlay was constructed using QGIS and overlayed on maps of the cave. The maximum radon concentration of 2625 Bq/m3 was measured in the Grand Hall, located in the central part of the cave following a narrow passage. The initial part of the cave near the entrance exhibited normal cave breathing characteristics, with radon concentrations of less than 300 Bq/m3. The deepest section of the cave, however, demonstrated an unexpected decrease in radon levels, temperature, and humidity. The average radon concentration in the Cango cave, measured at 1265 Bq/m3, is relatively low compared to other caves worldwide that need mitigation measures according to the International Commission on Radiological Protection (ICRP). [ABSTRACT FROM AUTHOR]

The equilibrium factor F is one of the parameters that should be considered when assessing the effective dose based on radon activity concentration. Since the equilibrium factor in various environments ranges theoretically from a value close to 0 to 1, it is expected that dose assessment based on one recommended coefficient value may lead to an underestimation or overestimation of the dose. That is why it is essential to measure this quantity if the basis for dose assessment is the radon concentration and not the concentration of radon decay products. The equilibrium factors were determined based on measurements of radon activity concentration and potential alpha energy concentration and varied from 0.15 to 0.94, with an arithmetic mean of 0.55. The average effective dose calculated for the employee taking into account these values was 31 mSv, assuming an annual working time of 1800 h. In turn, the average effective dose calculated for the equilibrium factor of 0.2 as recommended by the International Commission on Radiological Protection (ICRP) was equal to 13 mSv. [ABSTRACT FROM AUTHOR]

The radon concentration activity in buildings is influenced by various factors, including meteorological elements like temperature, pressure, and precipitation, which are recognized as significant influencers. The fluctuations of indoor radon in premises are related to seasonal change. This study aimed to understand better the effects of environmental parameters on indoor radon concentration levels in the Aksu school. Indoor and outdoor temperature differentials heavily influence diurnal indoor radon patterns. The analysis indicates that the correlation between indoor radon and outdoor temperature, dew point, and air humidity is weak and negligible for atmospheric pressure, wind speed, and precipitation, as determined by the obtained values of R2 and the Chaddock scale. The multiple regression model is characterized by the correlation coefficient rxy = 0.605, which corresponds to a close relationship on the Chaddock scale. [ABSTRACT FROM AUTHOR]

Fruit juices (FJs) are among the most popular beverages frequently preferred by consumers, believing FJs contain the nutritional values, minerals, phytochemicals, vitamins, and antioxidants necessary for a healthy life. However, FJs may contain natural radionuclides such as radon (222Rn), which originates from the fruit and water utilized in their production, at levels that may pose a health risk to people. Inhalation and ingestion of 222Rn gas increases the risk of lung and stomach cancer. In this study, commercially packaged FJs from the seventeen most popular brands consumed in Turkey were analyzed for physicochemical properties and 222Rn activity concentrations to evaluate the radiological health risk. The values of pH, brix and 222Rn activity concentrations in FJ samples varied from 2.68 to 4.28, 2.50 to 14.30%, 9.6 ± 1.1 to 25.2 ± 2.5 mBq/L, respectively. The radiological health risk caused by internal exposure was evaluated for children and adults by estimating the ingestion and inhalation annual effective dose. The average values of the total annual effective dose for children and adults were found as 0.039 µSv and 0.056 µSv, respectively, which are much lower than the recommended dose of 100 µSv for drinking water. [ABSTRACT FROM AUTHOR]

In this paper, the results of measurements of indoor radon activity concentration in fourteen elementary schools in Tuzla, Bosnia and Herzegovina, are presented. Measurements were performed with CR-39 solid-state nuclear track detectors. Radon activity concentration in investigated locations was 6.8-143 Bqm-3. To assess the indoor radon hazards for people, the annual effective dose, excess lifetime cancer risk, and the relative risk of lung cancer were estimated. [ABSTRACT FROM AUTHOR]

Radon, a radioactive gas, poses a significant health risk when accumulated in indoor environments. This study measured radon concentrations in three rooms with varying ventilation levels over a 12-month period, utilizing a Corentium monitor, an alpha spectroscopy-based radon detection device. The objective was to assess the impact of seasonal variations on indoor radon levels. The results indicated that the highest radon concentration, approximately 42 Bqm-3, was consistently observed in the closed room. In comparison, the partially closed room and the regularly occupied room with normal ventilation, had concentrations of 35 Bqm-3 and 31 Bqm-3, respectively. Across all three rooms, radon levels were lowest during the summer and peaked during the winter. The dose and risk associated with radon exposure were further analyzed using the RESRAD-BUILD computer code. All measured radon levels and associated doses were below the global safety limits. This study highlights the critical role of ventilation in controlling indoor radon levels and confirms that the environments studied remain within safe exposure thresholds. [ABSTRACT FROM AUTHOR]

There is a long-standing problem, posed by A.T.-M. Lau [ Fixed point theory and its applications , Academic Press, New York-London, 1976, pp. 121–129], whether left amenability is sufficient to ensure the existence of a common fixed point for every jointly weak^{\ast } continuous nonexpansive semigroup action on a nonempty weak^{\ast } compact convex set in a dual Banach space. In this note we discuss the current status of this problem and give a partial solution in the case of weak^{\ast } compact convex sets with the Radon–Nikodým property. [ABSTRACT FROM AUTHOR]

We study renormalized solutions to the problem $$\begin{align*} \begin{cases} -\Delta_pu=0 & \mbox{ in } \left\lbrace x \in \mathbb{R}^N : \left\lvert {x} \right\rvert>1\right\rbrace \\ \left\lvert {\nabla u} \right\rvert^{p-2}u_\nu + g(u) = \mu & \mbox{ on } \left\lbrace x \in \mathbb{R}^N : \left\lvert {x} \right\rvert=1\right\rbrace \end{cases} \end{align*} $$ { − Δ p u = 0 in { x ∈ R N : | x | > 1 } | ∇ u | p − 2 u ν + g (u) = μ on { x ∈ R N : | x | = 1 } where 1

BACKGROUND: Radon is a carcinogenic, radioactive gas that can accumulate indoors and is undetected by human senses. Therefore, accurate knowledge of indoor radon concentration is crucial for assessing radon-related health effects or identifying radon-prone areas. OBJECTIVES: Indoor radon concentration at the national scale is usually estimated on the basis of extensive measurement campaigns. However, characteristics of the sampled households often differ from the characteristics of the target population owing to the large number of relevant factors that control the indoor radon concentration, such as the availability of geogenic radon or floor level. Furthermore, the sample size usually does not allow estimation with high spatial resolution. We propose a model-based approach that allows a more realistic estimation of indoor radon distribution with a higher spatial resolution than a purely data-based approach. METHODS: A multistage modeling approach was used by applying a quantile regression forest that uses environmental and building data as predictors to estimate the probability distribution function of indoor radon for each floor level of each residential building in Germany. Based on the estimated probability distribution function, a probabilistic Monte Carlo sampling technique was applied, enabling the combination and population weighting of floor-level predictions. In this way, the uncertainty of the individual predictions is effectively propagated into the estimate of variability at the aggregated level. RESULTS: The results show an approximate lognormal distribution of indoor radon in dwellings in Germany with an arithmetic mean of 63 Bq/m³, a geometric mean of 41 Bq/m³, and a 95th percentile of 180 Bq/m³. The exceedance probabilities for 100 and 300 Bq/m³ are 12.5% (10.5 million people affected) and 2.2% (1.9 million people affected), respectively. In large cities, individual indoor radon concentration is generally estimated to be lower than in rural areas, which is due to the different distribution of the population on floor levels. DISCUSSION: The advantages of our approach are that is yields a) an accurate estimation of indoor radon concentration even if the survey is not fully representative with respect to floor level and radon concentration in soil, and b) an estimate of the indoor radon distribution with a much higher spatial resolution than basic descriptive statistics. [ABSTRACT FROM AUTHOR]

Indoor radon exposure is recognized as a significant cause of lung cancer, as shown by various epidemiological studies. One possible pathway for radon transport is through faults, where radon can escape into fractures and open spaces in rocks. Numerous studies link fault systems to elevated radon levels at the surface or within buildings. In Bulgaria, research on geogenic radon potential at a regional scale, especially for RPA (Radon Priority Areas) identification, is still in its early stages. This study aims to further investigate radon soil gas concentration on a regional scale and its correlation with fault systems in Sliven Province. In the study area, the majority of radon soil gas concentration measurements with higher values coincide with fault systems. However, the mechanisms of radon gas transport along these structures remain poorly defined and appear to be complex. [ABSTRACT FROM AUTHOR]

Radon as a daughter product from the radioactive uranium family, is present in all rocks and soils in the geosphere. Its half-life (3.82 d) allows the element to migrate from the terrestrial environment to the surface. This migration can be intensified through preferential degassing pathways, such as faults or fracture systems Geogenic radon potential refers to the tendency of high radon concentrations in a building, which is directly linked to surface influences rather than building materials. The radon index concept is employed to characterize GRP. This study aims to apply the multivariate cross-tabulation methodology at a specific site in Sofia, Bulgaria and to compare them with equation based "geogenic radon potential'. [ABSTRACT FROM AUTHOR]

All humans are exposed to radon, the primary source of natural radiation, which can harm people due to natural processes rather than human activity. Thus, it is of significant importance to determine the levels of radon in indoor, soil gas, water, and outdoors. Radon concentration (CRn) was measured in Kiraz district, İzmir, and the correlation between the indoor and soil gas CRn values was investigated. The indoor CRn values measured in 40 randomly selected dwellings in Kiraz exhibited a wide range from 19.50 ± 2.50 to 204.70 ± 8.00 Bq m−3 with an average value of 61.11 ± 4.23 Bq m−3. The measured indoor CRn values were compared to the reference levels in the world to help control radon in the dwellings. Indoor CRn values were lower than the ICRP reference level of 300 Bq m−3 in all of the dwellings studied. Furthermore, in 34 dwellings (representing 85% of the total number of dwellings studied), indoor CRn values were lower than the WHO reference level of 100 Bq m−3. Health hazard indices, namely annual effective dose (AED) and excess lifetime cancer risk (ELCR), were also calculated for each dwelling and compared with internationally acceptable levels to estimate the risk to human health. The AED values varied from 0.49 ± 0.06 to 5.16 ± 0.20 mSv y−1 with an average value of 1.54 ± 0.11 mSv y−1, which exceeds the world average of 1.15 mSv y−1 as reported by UNSCEAR. The ELCR values ranged from 2.05 ± 0.26 × 10−3 to 21.55 ± 0.84 × 10−3 with an average value of 6.43 ± 0.44 × 10−3, exceeding the world average of 0.29 × 10−3 as reported by UNSCEAR. The soil gas CRn values measured exhibited a wide variation ranging from 129.25 ± 6.38 Bq m−3 to 6172.64 ± 44.06 Bq m−3 with an average value of 1291.79 ± 18.70 Bq m−3. The soil gas CRn values were less than 10,000 Bq m−3; hence, the research area is categorized as "low radon risk areas" according to Sweden Criteria, and so no special constructions are required in the studied area. When soil gas CRn values were compared to indoor CRn values, no linear relationship was found between the CRn values. However, a strong positive linear correlation was found between indoor and soil gas CRn values less than 200 Bq m−3 and 2500 Bq m−3, respectively. [ABSTRACT FROM AUTHOR]

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Radon is a source of ionizing radiation that shows a carcinogenic potential. Thus, tracking radon exposure levels in the environment and managing exposure conditions is necessary for reducing the hazards such as lung cancer, which is known to be the second largest impact of radon on humans worldwide. A LR‐115 Type II strippable detector for monitoring radon radiation was installed in 30 mud and 26 block houses in the periurban (Duakor) areas in the Cape Coast Metropolis, Central Region, for 3 months to determine the exposure levels. The results showed that block houses (n = 26) had a radon ionization concentration in a range of 125–356 Bq m−3 and mean of 221 ± 61.4 Bq m−3, which was significantly higher than that of mud houses (n = 30), which ranged from 50.8 to 349 Bq m−3, with a mean of 186 ± 13.3 Bq m−3. About 80% and 10% of both types of houses showed levels that were above WHO's lower (100 Bq m−3) and upper (300 Bq m−3) limits of the annual residential guidelines. Moreover, over 70% of both building types showed annual effective doses of indoor radon levels that were within the action levels (3–10 mSv year−1). The data shows that the occupants have lived in their apartments for more than 10 years, while only about 3.0% have ever received some education on radon. Additional steps to manage indoor radon exposure in the community to avoid lung cancer are necessary. [ABSTRACT FROM AUTHOR]

Background: Radon is a radioactive gas and a major risk factor for lung cancer (LC). Methods: We investigated the dose–response relationship between radon and LC risk in the International Lung Cancer Consortium with 8927 cases and 5562 controls from Europe, North America, and Israel, conducted between 1992 and 2016. Spatial indoor radon exposure in the residential area (sIR) obtained from national surveys was linked to the participants' residential geolocation. Parametric linear and spline functions were fitted within a logistic regression framework. Results: We observed a non‐linear spatial‐dose response relationship for sIR < 200 Bq/m3. The lowest risk was observed for areas of mean exposure of 58 Bq/m3 (95% CI: 56.1–59.2 Bq/m3). The relative risk of lung cancer increased to the same degree in areas averaging 25 Bq/m3 (OR = 1.31, 95% CI: 1.01–1.59) as in areas with a mean of 100 Bq/m3 (OR = 1.34, 95% CI: 1.20–1.45). The strongest association was observed for small cell lung cancer and the weakest for squamous cell carcinoma. A stronger association was also observed in men, but only at higher exposure levels. The non‐linear association is primarily observed among the younger population (age < 69 years), but not in the older population, which can potentially represent different biological radiation responses. Conclusions: The sIR is useful as proxy of individual radon exposure in epidemiological studies on lung cancer. The usual assumption of a linear, no‐threshold dose–response relationship, as can be made for individual radon exposures, may not be optimal for sIR values of less than 200 Bq/m3. [ABSTRACT FROM AUTHOR]

Human exposure to indoor radon has been a subject of continuous concern due to its health implications, especially as it relates to lung cancer. Radon contaminates indoor air quality and poses a significant health threat if not abated/controlled. A seasonal indoor radon assessment of residential buildings of Obafemi Awolowo University was carried out to determine radon seasonal variability and to evaluate the cancer risk to the residents. AT-100 diffusion-based track detectors were deployed within living rooms and bedrooms for the radon measurement. During the rainy season, the average indoor radon concentration was 18.4 ± 10.1 Bq/m3, with higher concentrations observed in bedrooms compared to living rooms, whereas the average radon concentration was 19.0 ± 4.4 Bq/m3 in the dry season, with similar radon levels in living rooms and bedrooms. The potential alpha energy concentration values ranged from 1.62 to 7.57 mWL. The annual effective dose equivalent values were below the world average and recommended limits for public exposure. Of the three geological units underlying the residences, the buildings overlying the granite gneiss lithology have the highest radon concentrations with average value of 21.4 Bq/m3. The soil gas radon concentration to indoor radon concentration ratio over the granite gneiss lithology is 0.006. The estimated average lifetime cancer risk due to radon inhalation in the residences indicated a potential risk of cancer development in 178 persons in 100 000 population over a lifetime period. The average indoor radon concentrations were below the recommended limit, requiring no immediate remediation measures. Improved ventilation of residential apartments is recommended to minimize residents' risk to indoor radon. [ABSTRACT FROM AUTHOR]

In a study of 56 randomly selected Traditional Mud Houses (TMHs) in Nigeria, the radiation health impacts of radon progeny were evaluated using CR-39 radon detectors within a rainy season. The measured radon concentration ranged from 17 to 174 Bq m−3, with an average value of 76 Bq m−3 (SD = 36). This was lower than the WHO’s recommended reference level of 100 Bq m−3. However, 24% of the surveyed houses exceeded this level, indicating potential health risks. The estimated Potential Alpha Energy Concentration (PAEC) due to its progeny ranged from 1.84 to 18.81 mWL with an average value of 8.24 mWL (SD=3.91). The computed annual effective doses yielded an average value of 3.06 ± 1.44 mSv y¹, which is far less than the recommended reference level of 10 mSv y¹ by the International Commission on Radiological Protection. The lifetime excess absolute risks varied from 0.4 × 104 to 3.9 × 104, with an average of 1.7 ± 0.8 × 104. Improving the ventilation systems and applying cement plaster and distemper to the building walls and floors were recommended for older TMHs over 50 years old to mitigate radon exposure. This data can inform potential policy measures for indoor radon progeny control in Nigeria. [ABSTRACT FROM AUTHOR]

We prove pseudocompactness of a Tychonoff space X and the space of Radon probability measures on it with the weak topology under the condition that the Stone–Čech compactification of the space is homeomorphic to the space of Radon probability measures on the Stone–Čech compactification of the space X. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the extent of radon contamination in twenty-six drinking water samples from natural springs were collected from Dhirkot Azad Kashmir, along with four bottled mineral water samples. Radon gas escapes from the earth's crust due to uranium ores and diffuses into the atmosphere. This study assessed the levels of radon concentration, the yearly effective radiation dose, and carcinogenic risk from radon exposure in drinking water samples. The radon concentration varied from 0.28 to 30.25 Bq/L. The mean radon concentration of all samples was found to be 7.86 ± 2.3 Bq/L. The radon concentrations in bottled drinking water were found to be lower than those in natural springs. The statistical and GIS analyses included the use of interpolation and Pearson's correlation matrix. Seven samples had radon concentration that surpassed the standard limit established by the US-EPA, which is 11 Bq/L. The average annual effective dose from inhalation and ingestion was found to be lower than the value (0.1 mSv/y) provided by the WHO, but for some natural spring water samples, it exceeded the risk limit. The cancer risk revealed that 40% of the samples had an elevated lifetime cancer risk from radon exposure. Overall, the majority of the results obtained aligned with the worldwide guidelines established by the US-EPA. However, there were a few instances where the limits were exceeded, and constant monitoring is recommended. This study establishes a baseline for radon concentration in the area and provides a basis for future studies. [ABSTRACT FROM AUTHOR]

To assess the health impacts of radon exposure over a lifetime, in the present study, the annual effective dose (AED) and cumulative excess lifetime cancer risk (ELCR-C) were evaluated by considering various indoor microenvironmental exposures based on age-specific time–activity patterns using Monte Carlo simulations. Significant regional variations in indoor radon concentrations across the Republic of Korea were observed, with the highest levels found in schools and single detached houses. Based on the standard annual total of 8760 h spent indoors and outdoors, the AED varied by age group and dwelling type, with the ELCR-C for single detached houses being approximately 1.36 times higher than that for apartments on average. The present study highlights the importance of comprehensive health risk assessments that consider differences across indoor environments and age groups, indicating that limited evaluations of specific sites or areas may distort actual exposure levels. [ABSTRACT FROM AUTHOR]

The province of Gauteng in South Africa has a rich history of gold mining, which has driven economic growth and urbanization. Gold mining has also created over 270 gold mine tailings (GMT), now surrounded by human settlements due to a housing shortage. These GMT pose a health risk as they harbor elevated uranium, which over time undergoes radioactive decay to produce radon, a known lung carcinogen. This study aimed to investigate the potential correlation between the proximity to gold mine tailings (GMT) and indoor radon concentrations in Gauteng's residential dwellings. Volume activity of radon (VAR) inside 330 residential dwellings was measured in residential dwellings located proximally (<2 km) and distally (>2 km) to gold mine tailings using AlphaE radon monitors during winter. An interviewer-administered questionnaire was utilized to obtain data on factors that may influence indoor radon activities. Descriptive statistics and bivariate logistic regression analyzed the influence of proximity to gold mine tailings and dwelling characteristics on VAR. Furthermore, VAR was compared to the World Health Organization (WHO) radon reference level of 100 Bq/m3. Residential dwellings near gold mine tailings had significantly higher average indoor radon concentrations (103.30 Bq/m3) compared to the control group (65.19 Bq/m3). Residential dwellings proximal to gold mine tailings were three times more likely to have VAR beyond the WHO reference level of 100 Bq/m3. Furthermore, they had estimated annual effective doses of 2.60 mSv/y compared to 1.64 mSv/y for the control group. This study highlighted a concerning association between proximity to gold mine tailings and elevated indoor radon levels. Public health interventions prioritizing residential dwellings near gold mine tailings are crucial. Educational campaigns and financial assistance for radon mitigation systems in high-risk dwellings are recommended. Residents near gold mine tailings are encouraged to ensure continuous natural ventilation through frequent opening of windows and doors. [ABSTRACT FROM AUTHOR]

Radon (Rn) and helium (He) gases from uranium decay form distinct anomalies related to buried uranium deposits. In order to trace the geochemical anomalous sources from the volcanic-related uranium deposits in deeply buried areas, systematical Rn contents and He isotope ratios were analyzed from the Daguanchang uranium deposit. The soil gas Rn concentrations above the deep uranium are ten times higher than those in barren areas, indicating that instantaneous Rn content measurements can be used to detect deeply buried uranium. The helium isotope ratios (3He/4He) of the unmineralized samples from the mineralized drill hole (ZK1) are relatively lower and uniform compared to those of the samples from no-mineral drill hole (ZK2). However, the Th and U contents of the drill core samples from ZK1 are slightly lower than those of the samples from ZK2, indicating that the lower 3He/4He ratios in ZK1 are most likely due to the addition of 4He from underlying uranium intervals. The differences in the instantaneous Rn contents are consistent with the variations in the He isotope ratios of the drill core samples. These results demonstrate that soil gas Rn and 3He/4He ratios are useful tracers and can indicate the existence of deeply buried volcanic-related hydrothermal uranium ores. [ABSTRACT FROM AUTHOR]

This article focuses on the influence of occupants on the concentration of contaminants (radon Rn-222 and CO2) as well as the thermal comfort parameters. A series of sensors were placed to measure the concentration of the contaminants, temperature, and relative humidity in the test room at the Institute of Nuclear Physics PAN in Krakow (IFJ PAN), Poland. The test room is an office that is typical of the offices used in the facility. The occupants that used the space kept a detailed diary of their entry, exit, and number of people entering. The results showed that the accumulation of contaminants in such spaces may be severe and risks the health and safety of occupants. The accumulation of CO2 was extremely noticeable and did not diminish to the background level between the re-entry of the occupants to the office. The same was consistent for the radon concentration. The study shows how ventilation methods and small changes in occupant work strategy may influence the contaminant concentration within a test zone. [ABSTRACT FROM AUTHOR]

Traditionally, for indoor radon testing, predominantly passive measurements have been used, typically applying the solid-state alpha track-etch method for long-term and the charcoal method for short-term measurements. However, increasingly, affordable consumer-grade active monitors have become available in the last few years, which can generate a concentration time series of an almost arbitrary duration. Firstly, we argue that consumer-grade monitors can well be used for quality-assured indoor radon assessment and consequent reliable decisions. Secondly, we discuss the requirements of quality assurance, which actually allow for reliable decision-making. In particular, as part of a rational strategy, we discuss how to interpret measurement results from low-cost active monitors with high and low sensitivity with respect to deciding on conformity with reference levels that are the annual average concentration of indoor radon. Rigorous analysis shows that temporal variations in radon are a major component of the uncertainty in decision-making, the reliability of which is practically independent of monitor sensitivity. Manufacturers of low-cost radon monitors already provide sufficient reliability and quality of calibration for their devices, which can be used by both professional inspectors and the general public. Therefore, within the suggested measurement strategy and metrologically assured criteria, we only propose to clarify the set and values of the key metrological characteristics of radon monitors as well as to upgrade user-friendly online tools. By implementing clear metrological requirements as well as the rational measurement strategy for the reliable conformity assessment of a room (building) with radon safety requirements, we anticipate significant reductions in testing costs, increased accessibility, and enhanced quality assurance and control (QA/QC) in indoor radon measurements. [ABSTRACT FROM AUTHOR]

This study was conducted in the Najaf Governorate, Iraq, to analyze biological samples from smokers and non-smokers. Blood serum, urine, hair, and nails as a biological sample at five age groups were chosen to determine alpha emitters (222Rn, 226Ra, 218Po, and 214Po) using a CR-39 detector. The results show that the average values of radon concentrations (Bq m−3) in blood serum, urine, hair, and nails for smokers were 54 ± 19, 63 ± 20, 33 ± 9, and 40 ± 12 respectively. While, the average values of radon concentrations (Bq m−3) in blood serum, urine, hair, and nails for non-smokers were 23 ± 6, 30 ± 6, 18 ± 5, and 20 ± 6 respectively. Age and smoking affect all alpha emitters, according to the study's conclusions and comparisons. Significantly higher alpha emitters were seen in smokers compared to non-smokers (p < 0.01). Alpha emitter levels were significantly variable among age groups (p < 0.01). In smokers, greater levels were significantly linked to exposure time (p < 0.01). Smokers had greater mean values of 222Rn, 226Ra, 218Po, and 214Po in biological samples than non-smokers. Thus, it may be said that cigarette smoking is used as a biomarker of the presence of alpha emitters. [ABSTRACT FROM AUTHOR]

The surface exhalation rates of thoron and the mass exhalation rate of radon were investigated in soil and sand samples from Surat District, Gujarat, Bharat (India). Samples were collected from diverse locations, including river beds, beaches, public gardens, highways, ports, colleges, and farm fields. Analysis was performed using a SMART RnDuo Radon monitor (MX400). Soil exhalation rates of thoron varied from 2.00 (Bq/m2/h2) at Sarsana (G6) to 127.55 (Bq/m2/h2) at Hazira (G15), with an average rate of 36.16 (Bq/m2/h2) for Surat District. Radon mass exhalation rates ranged from 3.26 to 81.22 (mBq/kg/h), with a mean of 27.98 (mBq/kg/h), below the global average. This data serves as crucial reference information for potential nuclear or other facility planning in the region. [ABSTRACT FROM AUTHOR]

The aim of this study is to improve and simplify the measurement of radon exhalation rate using the closed-loop accumulation method. Based on the 222Rn concentration data obtained from reference the standard module of uranium ore sands and cement, this work simplifies the 222Rn concentration growth model for calculating radon exhalation rate using the least squares method and proves its accuracy. Through fitting residual analysis, anomalies are screened at the significance level of α = 0.05 to enhance fitting precision. Herein, the influence of the starting point on the fitting effect and the calculation of radon exhalation rate is explored. The results indicate that after screening anomalous data, the fitting effects of the two sets of experimental data are further improved, and the relative errors in radon exhalation rate measurements are reduced from 1.77 to 1.41% and 13.08 to less than 10% respectively. [ABSTRACT FROM AUTHOR]

Radon is a radioactive noble gas omnipresent in the environment, being part of the 238U and 232Th decay chains present in the Earth's crust. The gas can easily leak through the ground but also be present in natural construction materials and migrate into indoor places where it can be a carcinogen when inhaled. Studying the content and removal of indoor radon is crucial for the evaluation and mitigation of its radiological risks to public health. For more than 100 years, the removal by adsorption of the radon has been performed on activated charcoal. There is little progress in the field of radon adsorption at ambient conditions; the main progress is in the use of zeolite materials, having well-defined three-dimensional porous structures and radiation resistance. This study concerns a report on the state of the art of the application of zeolites in radon adsorption. Furthermore, an optimized approach for measuring the radon content in indoor environments and, consequently, its removal has been proposed. Adsorption systems based on zeolites have the potential to replace activated charcoal as a material of choice, allowing to facilitate the development of simple and compact radon adsorption systems. [ABSTRACT FROM AUTHOR]

Aims: We provide an overview of nationwide environmental data available for Denmark and its linkage potentials to individual-level records with the aim of promoting research on the potential impact of the local surrounding environment on human health. Background: Researchers in Denmark have unique opportunities for conducting large population-based studies treating the entire Danish population as one big, open and dynamic cohort based on nationally complete population and health registries. So far, most research in this area has utilised individual- and family-level information to study the clustering of disease in families, comorbidities, risk of, and prognosis after, disease onset, and social gradients in disease risk. Linking environmental data in time and space to individuals enables novel possibilities for studying the health effects of the social, built and physical environment. Methods: We describe the possible linkage between individuals and their local surrounding environment to establish the exposome – that is, the total environmental exposure of an individual over their life course. Conclusions: The currently available nationwide longitudinal environmental data in Denmark constitutes a valuable and globally rare asset that can help explore the impact of the exposome on human health. [ABSTRACT FROM AUTHOR]

We implement an inversion-based deblending method in the common midpoint gathers (CMP) as an alternative to the standard common receiver gather (CRG) domain methods. The primary advantage of deblending in the CMP domain is that reflections from dipping layers are centred around zero offsets. As a result, CMP gathers exhibit a simpler structure compared to common receiver gathers (CRGs), where these reflections are apex-shifted. Consequently, we can employ a zero-offset hyperbolic Radon operator to process CMP gathers. This operator is a computationally more efficient alternative to the apex-shifted hyperbolic Radon required for processing CRG gathers. Sparse transforms, such as the Radon transform, can stack reflections and produce sparse models capable of separating blended sources. We utilize the Radon operator to develop an inversion-based deblending framework that incorporates a sparse model constraint. The inclusion of a sparsity constraint in the inversion process enhances the focusing of the transform and improves data recovery. Inversion-based deblending enables us to account for all observed data by incorporating the blending operator into the cost function. Our synthetic and field data examples demonstrate that inversion-based deblending in the CMP domain can effectively separate blended sources. [ABSTRACT FROM AUTHOR]

Although many earthquake precursors have been proposed to forecast earthquakes, even in this modern era, short-term earthquake forecasting remains challenging due to the heterogeneous nature of the earthquake's occurrence. This study mainly focused on how the impending earthquake influences pre-earthquake scenarios using minor shocks and further confirmed by atmospheric parameters such as Outgoing Longwave Radiation (OLR). The Himalayan belt is one of the most at-risk areas during a continental-continental collision. The spatiotemporal analysis of the pre-earthquake scenario is carried out to identify the most vulnerable seismic risk zone and to forecast the probable magnitude of the earthquake. From the analysis, it is found that the accumulation of strain energy focussing near the epicenter of the impending earthquake. Furthermore, the study also revealed that abnormal changes in atmospheric parameters observed several days before an earthquake, which could serve as a precursor of seismic activity. On certain days, the anomalous OLR due to the radon gas emanation was observed at the different locations around the epicenter of the impending earthquakes. This phenomenon probably due to the transfer of accumulated strain from one side of the fault to other side of the fault through epicenter of the impending earthquake. This gives vital clue in determining the possible epicenter of the earthquake. The statistical analysis of minor shocks associated with significant earthquakes made it possible to determine the magnitude and depth range of minor shocks that may trigger the nucleation process for major earthquakes. The magnitude and depth ranges of microshocks involved in the nucleation process differed among fault types. This research highlights the importance of monitoring seismic and atmospheric activity to improve earthquake forecasting and preparedness. Hence, it is possible to identify the most vulnerable seismic zone, location of the epicenter and probable magnitude spatio-temporal analysis. [ABSTRACT FROM AUTHOR]

In this research, the radon gas concentration was measured for samples from the water of the Euphrates River in the Hindia district of Karbala governorate. The selected collection locations were 30 different local ones on the river between the ancient and modern bridges, heading north and south, respectively; the distance between locations was 100 meters. The concentrations and effective dose of radon were measured using the RAD7 device technology. The highest value was for sample 21, where the effective dose was (0.00001752 Bq/m³). The same value for the effective dose was of sample 7. The lowest value was in sample 27, where the effective dose was (0 Bq/m³), the same value of sample 3. It was observed from the study that the remaining values of the samples ranged from sample 1 as the lowest value of the effective dose (0.0799 Bq/m³) and also for sample 2 and sample 15. The highest value was for samples 29 and 23, where the value of the effective dose was (0.00001314 Bq/m³). However, from observing the results, these values are within the internationally permissible limits according to the recommendations of US Environmental Protection Agency, which is 11 Bq/L. [ABSTRACT FROM AUTHOR]

To assess public exposure to radon, thoron, and their progeny, measurements were conducted in 50 dwellings within the bauxite-rich area of Fongo-Tongo in western Cameroon. Passive integrating radon-thoron discriminative detectors (specifically RADUET) were employed for radon and thoron measurements. Additionally, concentrations of short-lived radon and thoron progeny were estimated using Direct Radon Progeny Sensors (DRPSs) and Direct Thoron Progeny Sensors (DTPSs) based on LR-115 detectors. The findings revealed indoor radon concentrations ranging from 31 to 123 Bq m−3 with a geometric mean (GM) of 62 Bq m−3, and indoor thoron concentrations ranging from 36 to 688 Bq m−3 with a GM of 242 Bq m−3. The Equilibrium Equivalent Radon Concentration (EERC) ranged from 3 to 86 Bq m−3 with a GM of 25 Bq m−3, while the Equilibrium Equivalent Thoron Concentration (EETC) ranged from 1.2 to 12.5 Bq m−3 with a GM of 7.6 Bq m−3. Notably, all dwellings recorded radon concentrations below 100 Bq m−3. Arithmetic means of radon and thoron equilibrium factors were calculated as 0.47 and 0.04, respectively. To assess annual effective doses from radon and thoron inhalation, equilibrium factors were used along with direct measurements of EERC and EETC. The differences observed in annual effective doses were 4.5% for radon and 42.5% for thoron. Furthermore, the contribution of thoron and its decay products to the annual effective dose from radon, thoron, and their progeny ranged from 12 to 94%, with an average contribution of 58%. Thus, this study found that the effective dose due to thoron inhalation in the study area exceeded that due to radon inhalation. It is concluded that, when evaluating radiation doses and health risks, it is crucial to consider both thoron and its progeny alongside radon and its progeny. This underscores the importance of considering direct measurements for accurately estimating radiation doses. [ABSTRACT FROM AUTHOR]

The epidemiological approach to converting radon exposure to effective dose is examined. Based on the definition of the effective dose, the dose conversion is obtained from the equivalence of lung-specific detriment associated with low-LET radiation and with radon exposure. This approach most reliably estimates effective dose per radon exposure on the basis of epidemiological data and implicitly includes the radiation weighting factor required to calculate the effective dose from radon exposure using the dosimetric approach, applying biokinetic and dosimetric models. Consistency between the results of the epidemiological and dosimetric approaches is achieved by using a radiation weighting factor of about 10 for alpha particles instead of the current ICRP value of 20. In contrast, the epidemiological approach implemented in ICRP 65, and referred to as dose conversion convention, was based on direct comparison of total radiation detriment with lung detriment from radon exposure. With the revision of radiation detriments in ICRP 103, this approach can be judged to overestimate the effective dose per radon exposure by about a factor of two because the tissue weighting factor for lung differs from the value of relative detriment to which it relates. [ABSTRACT FROM AUTHOR]

Radon, a radioactive gas can increase the risk of lung cancer when breathe in. Indoor Rn-222 and Rn-220 concentrations were determined using passive radon monitor in some dwellings in a Sn mining area of Jos Plateau. Outdoor gamma radiation was also measured with a hand-held survey meter. The range of Rn-222 and Rn-220 concentrations was from 7–53 Bq m−3 to 41–267 Bq m−3 with averages of 27 ± 17 and 92 ± 65 Bq m−3, respectively. The mean total effective dose due to Rn-222 + Rn-220 was estimated as 2.84 ± 1.57 mSv y−1. Rn-220 contributed between 50 and 95% to the total annual effective dose. There was no correlation between indoor Rn-220 and Rn-222 concentrations in the dwellings. Outdoor gamma radiation measured was between 0.31 ± 0.06 and 0.62 ± 0.08 μSv h−1, and mean annual effective dose calculated was 1.14 ± 0.21 mSv y−1. It is concluded from this study that thoron should not be neglected in dose assessment. [ABSTRACT FROM AUTHOR]

Radon (222Rn) is a widely used tracer in groundwater and surface water studies. In some applications of radon, samples need to be collected from deep submerged areas or discharge points such as caves or springs, locations typically accessed by scuba diving. However, there are no established sampling methods for collecting water by scuba diving for Rn analysis. We assessed four underwater sample collection methods: (a) injection into a catheter bag followed by transfer to a bottle after the dive, (b) air purging and then filling of a bottle by allowing gas to escape, (c) air purging followed by gas escape, and then overfilling of water with a syringe, and (d) collection with a syringe followed by transfer to a bottle. The samples were collected from the anchialine caves of the Yucatan Peninsula which are the longest underwater cave systems. The samples were analyzed using the same Rn‐in‐air analyzer and protocols. Statistical comparison of sampling at the same location with different methods showed no significant differences in Rn activity. No collection method is superior in terms of measurement quality; operational simplicity is thus preferred. Statistically significant differences in activity were observed between fresh and saline samples from the same cave, with higher activities in the fresh samples, regardless of sampling method. The saline groundwater therefore has a lower residence time, suggesting vigorous landwards flow. Our assessment shows that in situ sampling of discrete water samples for Rn tracing by divers is a useful and powerful approach allowing the study of otherwise impossible sites. Key Points: Different underwater sample collection methods by scuba divers for Rn‐in‐water was assessedAll four tested methods showed no differences in measured Rn activityRadon is higher in saline groundwater versus fresh water in anchialine submerged caves of the Yucatan Peninsula [ABSTRACT FROM AUTHOR]

The observation of precursory signals of the 2021 Chamoli rock–ice avalanche provides an opportunity to investigate the multidisciplinary analysis approach of rock failure. On 7 February 2021, a huge rock–ice mass detached from the Raunthi peak at Chamoli district in Uttarakhand, India. The tragic catastrophe resulted in more than 200 deaths and significant economic losses. Here, we analyse radon concentration and seismic signals to characterise the potential precursory anomalies prior to the detachment. Continuous peaks of radon anomalies were observed from the afternoon of 5 to 7 February and decreased suddenly after the event, while a cumulative number of seismic tremors and amplitude variations are more intensified ~2.30 h before the main event, indicating a static to dynamic phase change within the weak zone. This study not only characterises abnormal signals but also models the rock failure mechanisms. The analysis unveils three time‐dependent nucleation phases, physical mechanisms of signal generation and a complete scenario of physical factors that affected the degree of criticality of slope failure. The results of this study suggest gradual progression of rock cracks/joints, subsequent material creep and slip advancement acceleration preceded the final failure. Furthermore, the study highlights the importance of an early warning system to mitigate the impact of events like the 2021 Chamoli rock–ice avalanche. [ABSTRACT FROM AUTHOR]

We study the existence of solutions to the problem - Δ u + u p - M ∇ u q = 0 in Ω , (1) u = μ on ∂ Ω in a bounded domain Ω, where p > 1, 1 < q < 2, M > 0, μ is a nonnegative Radon measure in ∂Ω, and the associated problem with a boundary isolated singularity at a ∈ ∂Ω, - Δ u + u p - M ∇ u q = 0 in Ω , (2) u = 0 on ∂ Ω \ α. The difficulty lies in the opposition between the two nonlinear terms which are not on the same nature. Existence of solutions to (1) is obtained under a capacitary condition μ K ≤ c min cap 2 p , p ′ ∂ Ω , cap 2 - q q , q ′ ∂ Ω for\;all\;compacts\; K ⊂ ∂ Ω. Problem (2) depends on several critical exponents on p and q as well as the position of q with respect to 2 p p + 1 . [ABSTRACT FROM AUTHOR]