Background: With growing concern during the COVID-19 pandemic, indoor environmental quality has received significant attention. Radon, a radioactive gas produced from the decay of radium found in soil, rocks, and building materials, can accumulate indoors, posing serious health risks such as lung cancer. University environments, where occupants spend significant time indoors, are particularly susceptible to prolonged radon exposure. Method: This study focused on the estimation of indoor radon concentrations from multiple university buildings in Shanghai. A field investigation was conducted between June 2020 and August 2022. Continuous radon measurements were conducted in the dormitories and classroom buildings. Environmental factors include indoor air temperature and relative humidity. Results: Radon concentrations were influenced by season, floor level, and measurement period, with the highest concentrations recorded during summer and on lower floors due to reduced ventilation. The mean radon concentration in dormitories was 14.8 +/- 9.2 Bq/m3, and in classrooms 12.6 +/- 6.7 Bq/m3, both below national safety limits and lower than those in the pre-pandemic era. Seasonal effect, floor level, and time of measurement were the significant factors for indoor radon concentrations. Conclusion: This study has identified the main factors that affect indoor radon concentration in university campus. The radon concentrations at the lower floor levels remain the highest in the building. The results provide evidence for conducting refined radon monitoring and risk assessment in campus environment, especially during the summer.

Radon-222 is a naturally occurring gas produced by the natural radioactive decay of Uranium, which is present in soil and rock. readily emanates from the soil and passes into the air, where it decays and emits alpha particles and produces a series of short-lived particles (Polonium-218, Polonium-214, and Polonium-210) that also decay by emitting alpha particles. People inhale the short-lived particles, these can cause significant damage to the inner cells of the bronchioles and may also lead to the development of lung cancer. For reasons stated above, it is of utmost importance to measure and evaluate the levels of exposure due to Radon. In this research work, concentration of Radon-222 is determined in 26 workplaces located in basements belonging to 10 buildings in the city of Lima, Peru. the measurements, LR-115 Type 2 detectors are used, which are placed on the walls of the basements under study at three levels, 100 cm and 160 cm high, measured from the floor. The detectors are then recorded and read following the protocol used in the Laboratory of the Nuclear Fingerprint Technique Research Group of the PUCP (GITHUNU-PUCP). The statistical results show that 12 workplaces presented concentration levels greater than 150 Bq/m3, in different measurement periods, and this was due to limitations in ventilation in these environments. In addition, using the Pearson coefficient, it was possible to evaluate the correlation of the concentration of radon-222 relative humidity and temperature, in 20 work environments. Of these, only one environment shows a significant positive linear correlation between concentration and temperature; and only one environment shows a significant negative linear correlation between concentration relative humidity. From this we conclude that meteorological variables of humidity and temperature probably do not significantly influence the concentration of radon-222 in this type of enclosure.

Compacted soil layers effectively prevent the migration of radon gas from uranium tailings impoundments to the nearby environment. However, surface damage caused by wet and dry cycles (WDCs) weakens this phenomenon. In order to study the effect of crack network on radon exhalation under WDCs, a homemade uranium tailing pond model was developed to carry out radon exhalation tests under five WDCs. Based on image processing and morphological methods, the area, length, mean width and fractal dimension of the drying cracks were quantitatively analyzed, and multiple linear regression was used to establish the relationship between the geometric characteristics of the cracks and the radon exhalation rate under multiple WDCs. The results suggested that the radon release rate and crack network of the uranium tailings pond gradually stabilized as the water content decreased, following rapid development in a single WDC process. The radon release rate increased continuously after each cycle, with a cumulative increase of 25.9% over 5 cycles. The radon release rate and average crack width remained consistent in size, and a binary linear regression considering width and fractal dimension could explain the changes in radon release rate after multiple WDCs.

Radon is a naturally occurring radioactive gas found in rocks, soil, and building materials. Precisely because of its gaseous nature, it tends to concentrate in indoor environments, resulting in a danger to human health. The effects of radon have been described, documented, and attested by the international scientific community and recognized as the second cause of lung cancer after cigarette smoking and in synergy with it. In December 2013, the Council of the European Union issued Council Directive 2013/59/Euratom, which establishes basic safety standards relating to protection against the dangers deriving from exposure to ionized radiation and managing the health risks associated with radon. In addition, designing buildings against radon risk in synergy with the use of low environmental impact materials is one of the objectives of building sustainability certifications. This work presents how radon creeps into buildings and reports several technologies that are needed to remove and mitigate the risk associated with indoor radon in existing and new buildings.

Northern lakes are a source of greenhouse gases to the atmosphere and contribute substantially to the global carbon budget. However, the sources of methane (CH4) to northern lakes are poorly constrained limiting our ability to the assess impacts of future Arctic change. Here we present measurements of the natural groundwater tracer, radon, and CH4 in a shallow lake on the Yukon-Kuskokwim Delta, AK and quantify groundwater discharge rates and fluxes of groundwater-derived CH4. We found that groundwater was significantly enriched (2000%) in radon and CH4 relative to lake water. Using a mass balance approach, we calculated average groundwater fluxes of 1.2 +/- 0.6 and 4.3 +/- 2.0 cm day(-1), respectively as conservative and upper limit estimates. Groundwater CH4 fluxes were 7-24 mmol m(-2) day(-1) and significantly exceeded diffusive air-water CH4 fluxes (1.3-2.3 mmol m(-2) day(-1)) from the lake to the atmosphere, suggesting that groundwater is an important source of CH4 to Arctic lakes and may drive observed CH4 emissions. Isotopic signatures of CH4 were depleted in groundwaters, consistent with microbial production. Higher methane concentrations in groundwater compared to other high latitude lakes were likely the source of the comparatively higher CH4 diffusive fluxes, as compared to those reported previously in high latitude lakes. These findings indicate that deltaic lakes across warmer permafrost regions may act as important hotspots for CH4 release across Arctic landscapes.