NH8.2 | Radon and natural radioactivity: implications from the geogenic sources to the human health risk
EDI
Radon and natural radioactivity: implications from the geogenic sources to the human health risk
Convener: Alessandra Sciarra | Co-conveners: Eleonora BenàECSECS, Livio Ruggiero, Eric PetermannECSECS
Orals
| Fri, 28 Apr, 08:30–10:05 (CEST)
 
Room 1.34
Posters on site
| Attendance Fri, 28 Apr, 10:45–12:30 (CEST)
 
Hall X4
Posters virtual
| Attendance Fri, 28 Apr, 10:45–12:30 (CEST)
 
vHall NH
Orals |
Fri, 08:30
Fri, 10:45
Fri, 10:45
Natural radioactivity fully affects our environment due to cosmic radiation from space, the interaction between the cosmic radiation and the atmosphere (e.g. 14C, 7Be, 3H) and the terrestrial source from soil and minerals in rocks linked to and the alpha decay processes of the principal primordial radionuclides (e.g. 238U, 232Th, 40K). Among the terrestrial sources, radon (222Rn) gas is considered the major source of ionizing radiations exposure to the population and an indoor air pollutant due to its harmful effects on human health (cancerogenic, W.H.O.).
In particular, the Geogenic Radon (GR) exerts the main control on Indoor Radon Concentrations (IRC), as a consequence, the identification of areas characterized by enhanced Geogenic Radon is critical in hazard assessment. For this reason, the studies of radon transport and migration mechanisms are used in various fields of the geosciences, (e.g. air, soil, water and indoor measurements) and represents a powerful investigation tool as concerns the radiation protection. In fact, radon migration and transport in-soil and the surface emission are controlled by geogenic and tectonic sources; radon migration along permeable pathways (e.g. seismically active and not-active faults, fractured zones) may enhance the Rn content at surface modifying the shallow distribution of the geogenic activities. In contrast, the indoor radon concentrations at surface are defined by other anthropogenic and meteorological factors (e.g. permeability, buildings and architectural features, ventilation, occupation patterns).
This session aims, into details, to improve the knowledge of radon concentration and migration mechanisms in the different geological compartments (e.g. minerals, rocks, soil, water) with the further implications in the IRC to assess health hazard from radon exposure, including: (i) the study of the different GR sources and components; (ii) the Geogenic Radon Potential (GRP) mapping; (iii) the identification of the Radon Priority Areas (RPA); (iv) the radon health hazard assessment (EURATOM 59/2013); (v) groundwater contamination; (vi) volcanic and active system monitoring and surveillance; (vii) atmospheric tracing, including of greenhouse gases and pollutants.
Contributions on novel methods and instrumentation for environmental radioactivity monitoring are also encouraged.

Orals: Fri, 28 Apr | Room 1.34

Chairpersons: Eleonora Benà, Eric Petermann, Alessandra Sciarra
08:30–08:35
08:35–08:45
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EGU23-2821
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ECS
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On-site presentation
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Mirsina M. Aghdam, Carlos Rocha, and Quentin Crowley

The Irish population receives most of its annual average radiation dose from radon (including thoron), but there is considerable spatial variation in parameters that affect these concentrations. An assessment of natural radioactivity levels and radon and thoron exhalation rates was conducted in County Carlow and Kilkenny, where evidence of "high indoor radon" concentrations was found. Background data used in this study include airborne radiometric data and stream sediment geochemistry from the TELLUS project, and indoor radon concentrations as supplied by Ireland’s Environmental Protection Agency. Based on the analysis of these datasets, a set of soil samples was taken from the study area in the first phase of the project. The exhalation rates of radon and thoron for collected samples were determined in the laboratory. The resultant data were classified based on geological and soil type parameters. Geological boundaries were found to be robust classifiers for radon exhalation rates and radon-related variables, whilst soil type classification better differentiates thoron exhalation rates and correlated variables. In the second part of the project, a detailed investigation of geogenic radon potential (GRP) was carried out in an identified hotspot area near Graiguenamanagh town (County Kilkenny, Ireland) by using spatial regression analysis of radon-related variables to evaluate the exposure of people to natural radiation (radon, thoron and gamma radiation). To model radon release potential at different points, an ordinary least squared (OLS) regression model was developed in which soil gas radon (SGR) concentrations were considered as the response value. Proxy variables such as radionuclide concentrations obtained from airborne radiometric surveys, soil gas permeability, distance from major faults, and a digital terrain model were used as input predictors. ArcGIS and QGIS software together with XLSTAT statistical software were used to visualise, analyse and validate the data and models. The proposed GRP models were validated through diagnostic tests. Empirical Bayesian kriging (EBK) was used to produce a map of the spatial distribution of predicted GRP values and to estimate the prediction uncertainty. The methodology described here can be extended for larger areas and the models could be utilised to estimate the GRPs of other areas where radon-related proxy values are available.

How to cite: M. Aghdam, M., Rocha, C., and Crowley, Q.: A Detailed Investigation and Modeling of Natural Radioactivity Levels and Radon/Thoron Release Potentials in Southeastern Ireland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2821, https://doi.org/10.5194/egusphere-egu23-2821, 2023.

08:45–08:55
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EGU23-13566
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ECS
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On-site presentation
Johannes Mair, Andreas Henk, and Rouwen Lehné

Within the framework of the project Neotectonics in the Northern Upper Rhine Graben (NeoNORG), the relationship between fault zones in a sedimentary basin and associated radon anomalies is investigated. The area of interest is located west of Darmstadt near the village Wolfskehlen. Radon levels in the Quaternary strata of the Upper Rhine Graben are generally low or moderate. However, tectonic fault zones could represent pathways of increased gas permeability and advective gas transport which would result locally in elevated soil radon concentrations. 

A multi-method geophysical approach was chosen to visualise the subsurface structure. Each method has different advantages in terms of penetration depth and resolution (i.e., electrical resistivity tomography, ground penetrating radar and seismics of different wave types). The combination of these different geophysical investigation methods allows to trace the fault zones from the crystalline basement of the sedimentary basin at a depth of 2 km to several metres below the earth's surface.

To investigate the relationship between radon concentration and fault zones, soil gas measurements were carried out at the surface along several profiles. In total 800 soil gas measurements were conducted, in which 600 active short-term measurements were conducted by soil gas sampling and 200 passive long-term measurements (three-week exposure period) were conducted using exposimeters. In addition, parameters such as soil material, weather conditions and soil permeabilities were recorded.

The evaluation of the measurements indicates no direct influence of the fault zones on the measured radon levels. Instead, there are very distinct correlations with the soil substrate and weather conditions. The preliminary results suggest that the migration of radon or the accumulation of primordial radionuclides along fault zones is superimposed by stronger signals such as weather and soil material in the study area of the Northern Upper Rhine Graben.

How to cite: Mair, J., Henk, A., and Lehné, R.: Soil properties and weather conditions mask a potential tectonic contribution to radon concentrations measured in soil air – a case study from the northern Upper Rhine Graben, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13566, https://doi.org/10.5194/egusphere-egu23-13566, 2023.

08:55–09:05
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EGU23-6245
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ECS
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Virtual presentation
Raffaella Silvia Iovine, Rosario Avino, Emilio Cuoco, Carmine Minopoli, Alessandro Santi, Stefano Caliro, Antonio Piersanti, Gianfranco Galli, and Monica Piochi

This study, conducted in the frame of the Pianeta Dinamico project funded by Istituto Nazionale di Geofisica e Vulcanologia, aims to improve the knowledge of radon concentration dissolved in several different waters from some of the Italian volcanic areas and its relationships with lithological and structural settings, fluid chemistry and circulation, volcano dynamics.

The study mainly focuses on 222Rn variations over time in thermal waters of the Campi Flegrei caldera at NW of Naples, an active volcanic field hosting an important geothermal system and one of the most dangerous calderas in the world. The caldera, part of the SW-NE trending fissure-like feeding system of the Phlegraean Volcanic District including also Ischia island, lastly erupted in 1538 and, since 2000, has been under a permanent unrest with up 1 metres of uplift, thousands of earthquakes and tons of CO2 emissions.

25 sites were sampled and analysed for dissolved 222Rn levels at least twice per year since October 2021; starting from October 2022, 5 waters were then selected for monthly monitoring with the goal of unravelling exogenous (e.g., temperature or rainfall) versus endogenous processes relationships.

In order to compare radon concentrations in the caldera with those in the volcanic context of southern Italy, we sampled and analysed as follows: a) 23 cold waters at Somma-Vesuvius, the stratovolcano placed at the intersection of regional NW–SE and NE–SW fault systems east of Naples, showing mild gaseous emissions after the 1944 eruption; b) 8 cold waters from the north of Campi Flegrei caldera, i.e. 7 from a multi-layer aquifer at the base of the extinct Roccamonfina stratovolcano and 1 water at Minturno (northern edge of Roccamonfina); c) 1 thermal water belonging to Ischia at the NW corner of the Gulf of Naples; d) 3 thermal waters of the Vulcano island from the Sicilian Aeolian Arc, characterised by vigorous seismic and fumarolic degassing activities that has shown an abrupt increase on August 2021.

The waters are springs, lakes, pools, and groundwater; two are from Le Fumose (Campi Flegrei) and Porto Ponente (Vulcano) submerged emissions.

Measurements have been performed by a Radon-in-air detector (RAD7®, Durridge Co.) equipped with Big Bottle RAD H2O and DRYSTIK accessories and processed using the CAPTURE program.

Campi Flegrei reaches the highest radon concentrations, varying from 0.20 ± 0.03 to ~1887 ± 13 Bq/L. Somma-Vesuvius shows from almost no radon to 24 ± 1 Bq/L, and Ischia is at 54 ± 2 Bq/L.

Roccamonfina area has a discrete variability from 0.2 ± 0.1 to ~ 71 ± 7 Bq/L at SE, being 9.0 ± 0.4 Bq/L at Minturno.

Vulcano island attains the lowest detected concentrations, less than 2.4 ± 1.0 Bq/L.

Dealing with different areas, the presented results lay the groundwork for better understanding radon behaviour and evaluating the implications on environmental and volcanic hazards assessment. At Campi Flegrei where, in 2012, the alert level was raised from base to warning, radon should be useful to investigate processes from which volcanic dynamics originates and to corroborate the monitoring outcomes.

How to cite: Iovine, R. S., Avino, R., Cuoco, E., Minopoli, C., Santi, A., Caliro, S., Piersanti, A., Galli, G., and Piochi, M.: Radioactivity and volcanic areas: radon concentrations in waters from the unresting Campi Flegrei caldera and other volcanoes in Southern Italy using a RAD7 radon detector, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6245, https://doi.org/10.5194/egusphere-egu23-6245, 2023.

09:05–09:15
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EGU23-6710
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ECS
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On-site presentation
Davide Romano, Salvatore Magazù, Giuseppe Sabatino, Marcella Di Bella, and Francesco Italiano

North-eastern Sicily can be considered a radon-prone area due to the presence of a Variscan crystalline basement, that includes high-radionuclides content rocks such as low to high-grade metamorphites and felsic plutonic rocks. The area is also characterized by intense seismic activity: the Mw 7.1 seismic event that struck this area on 28th December 1908 is still the deadliest earthquake recorded in Europe, having caused more than 120,000 casualties. Despite the proven link between high radon concentrations and some geogenic and tectonic settings (e.g. seismogenic areas and volcanic and crystalline rock environments), no radiological data had been collected for north-eastern Sicily. In order to fill this gap, a series of radiological surveys were performed in a sector of this vulnerable area with the aim of determining the radon concentration in soil gases and groundwaters.

Radon dissolved in groundwater was derived in the range of 1.6–57.5 Bq L-1, well below the limit of 100 Bq L-1 set by the Italian Legislation (D. Lgs. 28/2016). Concerning soil gases, radon and thoron levels range from <1 to 81 kBq m-3 and from 3 to 123 kBq m-3, respectively. All those values are quite similar to those recorded in the adjacent Region of Calabria by previous studies.

Although the health risk due to ingestion and inhalation of groundwater can be neglected, the presence of several soil radon anomalies testifies a potentially harmful effect on the population. Radon index maps, built based on the measured radon concentration and the permeability of the soil, highlight that parts of the investigated area are characterized by an enhanced hazard. Those maps might have a useful role in preliminary screening activities related to the identification of the so-called Radon Priority Areas (EURATOM 59/2013 and Italian legislative decree 101/2020).

Soil-radon anomalous values seem to have a tectonic origin and are presumably associated with the presence of fault segments probably representing the on-land continuation of a transtensional fault zone located in the southern Tyrrhenian Sea between the Aeolian Island and the northern margin of Sicily. In this context, the seismic and radiological hazards are strictly connected, further complicating the mitigation strategies against those geological processes. Since this study illustrates the first radiological data collected in this sector of the southern Apennines of Italy, a lot of work has to be done in the near future. The main goals are to extend radon investigation in other sectors of north-eastern Sicily as well as to perform a series of indoor radon measurements to determine if a clear correlation exists between high soil radon areas and high indoor radon levels.  

How to cite: Romano, D., Magazù, S., Sabatino, G., Di Bella, M., and Italiano, F.: First radon dataset from the seismic area of north-eastern Sicily, Italy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6710, https://doi.org/10.5194/egusphere-egu23-6710, 2023.

09:15–09:25
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EGU23-4528
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Highlight
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On-site presentation
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Peter Bossew, Giorgia Cinelli, Javier Elío, and Eric Petermann

Radium-226, part of the 238U decay chain, which is ubiquitous in the ground, generates a terrestrial gamma ray field which can be detected above ground, through its strongly gamma radiating progeny 214Bi and 214Pb and to minor degree through 226Ra itself. The measurand is ambient dose equivalent rate, ADER, nSv/h, that also includes contribution from cosmic rays and other terrestrial radionuclides (i.e. 40K and 232Th decay chain). On the other hand, its decay produces 222Rn (here shortly Rn) which can migrate through the ground and lead to measurable Rn concentration (Bq/m³) in ambient media, namely soil, ground water and the indoor and outdoor atmosphere. One can therefore expect that originating from the same source, ADER and Rn are statistically related and ADER may serve as predictor of Rn related quantities, such as mean Rn concentration over an area, its probability to exceed a level or the status of an area as radon priority area. However, as the pathway from Ra in the ground to ambient Rn is complex, and as measured ADER has also other contributions than Ra, the relation must be expected to be blurred by nuisance factors, which pose a challenge to analysis.

A large and ever increasing dataset of ADER is freely available from the Citizen Science project Safecast [1], founded in Japan after the Fukushima accident 2011. It has since spread over the entire world (with measurements in regionally very different density, though) and by late 2022, the dataset comprised 180M measurements, of which about 50M in Europe. The measurements were performed with a standard instrument called bGeigie nano, of which several 1000 circulate around the globe, used by voluntary citizen scientists who send their data to Safecast. On the other hand, in Europe a good indoor Rn concentration (IRC) database is available, based on about 1.2M individual measurements [2], as well as an interpolated European IRC map [3].

Thus, we relate ADER (Safecast) with IRC and derived quantities, both aggregated on a common 10 km × 10 km grid. Raw ADER is reduced by cosmic dose rate (related to altitude a.s.l., accessible from digital elevation database) and mean internal detector background. Since it can be assumed that ADER on a point depends on its urbanization status (due to the influence of building materials which also contain gamma radiating nuclides), this factor is also investigated. 

First results are promising and will be shown in the presentation.

 

[1] https://safecast.org/

[2] European Commission, Joint Research Centre – Cinelli, G., De Cort, M. & Tollefsen, T. (Eds.), European Atlas of Natural Radiation, https://remon.jrc.ec.europa.eu/About/Atlas-of-Natural-Radiation/Download-page

[3] Elío J., et al. (2019): The first version of the Pan-European Indoor Radon Map. Nat. Hazards Earth Syst. Sci., 19, 2451–2464, https://doi.org/10.5194/nhess-19-2451-2019

How to cite: Bossew, P., Cinelli, G., Elío, J., and Petermann, E.: Can citizen science ambient dose rate data (Safecast) be used for predicting indoor radon?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4528, https://doi.org/10.5194/egusphere-egu23-4528, 2023.

09:25–09:35
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EGU23-2319
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On-site presentation
Sebastian Baumann, Valeria Gruber, Eric Peterman, and Giorgia Cinelli

Radon is a radioactive noble gas built in the uranium – radium decay chain. Accumulated indoor radon concentrations can cause lung cancer. The reduction of indoor radon concentrations is a health political topic, noticing indoor radon is a large source of radiation exposure. The delineation of areas with high radon risk is an essential task to effective implement radon protection measures. The methods for delineation range from aggregate statistics of indoor radon concentrations to data driven machine-learning techniques with multiple predictors.

The main factors determining indoor radon concentrations are geogenic parameters (e.g. uranium content, permeability of the soil), building characteristics (e.g. sealing against the underground) and using habits (e.g. air exchange rate). Radon is not only a radiation protection topic. Outdoor radon and radon flux is used in atmospheric sciences as tracer for greenhouse gases and as input variable for atmospheric modelling.

We investigate the possibility using outdoor radon and radon flux to predict areas with high radon risk, by comparing these parameters with other parameters used for radon risk prediction as geological information, uranium content of the soil or weather data. We use the gridded indoor radon concentrations of the European Atlas of Natural Radiation as basis to define if an area shows high indoor radon concentrations. We perform a correlation analysis of the above-mentioned parameters. Further, we predict the gridded indoor radon concentrations with a random forest model and calculate feature importance for the selected model to investigate which parameters have the most impact on the prediction.

This research is part of project 19ENV01 traceRadon.  The project 19ENV01 traceRadon has received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme.

How to cite: Baumann, S., Gruber, V., Peterman, E., and Cinelli, G.: Using outdoor radon and radon flux to predict areas with high radon risk, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2319, https://doi.org/10.5194/egusphere-egu23-2319, 2023.

09:35–09:45
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EGU23-11677
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ECS
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On-site presentation
Diana Altendorf, Hannes Grünewald, Jörg Dehnert, Michal Duzynski, Ralf Trabitzsch, and Holger Weiß

Since new radon risk maps for Germany were published in 2021, in Saxony the highest spatial accumulation of precautionary areas can be found. Reasons are the geological subsoil like the Ore Mountains, as well as a historical mining industry and intensive uranium mining from 1946 to 1990.

Close to a heap, various ventilation experiments for indoor radon reduction were performed in a two-room flat (ground floor) in Bad Schlema (Germany). As an innovative approach to eliminate indoor radon and prevent new radon from entering, the focus is on creating an over pressure within the flat. This developed ventilation mode, which aims to ensure that more fresh air enters the room than leaves it, is called differential pressure mode with a forced over pressure.

Therefore, a decentralised ventilation system with heat-recovery from inVENTer (Germany) was installed. Throughout numerous different ventilation experiments, radon activity concentrations [Rn] were continuously measured in all rooms (including basement and balcony) using Radon Scout Plus devices from SARAD (Germany). Thereby, room-specific radon behaviour with and without ventilation was found.

Despite a strong seasonal trend with significantly higher indoor radon levels in Sep.-Nov. and Dec.-Feb. than in June-Aug., an overall reduction of indoor radon of up to 80 % was achieved. Important to mention is that different ventilation modes in combination with different fan performance levels resulted in different indoor radon reductions.

Here, in particular, the experiments with forced over pressure (up to +5 Pa) led to significant results in summer and winter, even in rooms with higher [Rn]. For example, measured [Rn] of 7.000 Bq/m3 within the kitchen could be reduced to 300 Bq/m3 and maintained for the entire duration of the respective ventilation experiment.

In this work, the performed experiments as well as the room-specific ventilation effect will be presented. Furthermore, this work analyses the dependencies between the reduction of indoor radon activity concentration and the corresponding environmental parameters.

How to cite: Altendorf, D., Grünewald, H., Dehnert, J., Duzynski, M., Trabitzsch, R., and Weiß, H.: Efficient indoor radon reduction by over pressure ventilation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11677, https://doi.org/10.5194/egusphere-egu23-11677, 2023.

09:45–09:55
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EGU23-5816
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Highlight
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Virtual presentation
Claudia Grossi, Scott Chambers, Daniel Rabago, Luis Quindos, Roger Curcoll, Viacheslav Morosh, Stefan Röttger, Alessandro Rizzo, Marta Fuente, and Arturo Vargas

The noble and radioactive gas radon is well known to be the most important source of public exposure to natural environmental radioactivity in indoor environments (workplaces, homes, etc.). Consequently, it is important to identify radon-prone areas, where radon fluxes are high, and also to develop and apply mitigation measures when radon activity concentrations of indoor areas exceed guideline values.

However, radon is also known by the climate and atmospheric research communities to be a useful environmental tracer and it is nowadays being used in several studies such as the improvement of atmospheric transport models or the indirect estimation of GHG fluxes by the Radon Tracer Method. These previous applications will benefit from the availability of radon flux maps.

Stakeholders and scientists involved in radiation protection and climate analysis may benefit from reliable continuous radon flux measurements to validate and improve existing and future radon flux maps. In the framework of the project traceRadon (EMPIR reference 19ENV01) a full metrology chain has been designed and built for radon flux measurements.

The work and the challenges related to this type of measurement will be presented here together with possible guidelines for carrying out continuous radon flux measurements in the field.

How to cite: Grossi, C., Chambers, S., Rabago, D., Quindos, L., Curcoll, R., Morosh, V., Röttger, S., Rizzo, A., Fuente, M., and Vargas, A.: Reliable radon flux observations for supporting Radiation Protection and GreenHouse Gase reduction strategies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5816, https://doi.org/10.5194/egusphere-egu23-5816, 2023.

09:55–10:05
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EGU23-10265
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Virtual presentation
Maria Meirelles and Vasconcelos Helena

Radon is a radioactive gas that has no smell, colour or taste and them its half-life are approximately 3.825 days. It is produced from the natural radioactive decay of uranium, which is found in all rocks and soils. Is the heaviest of all noble gases and has a total of 36 isotopes ranging from 193Rn to 228Rn. Radon is a naturally occurring radioactive gas which may be found in high concentrations in indoor environments, such as homes and workplaces. Radon signals at shallow depths are mainly influenced by environmental parameters, such as atmospheric pressure, temperature, groundwater level, and precipitation. The values observed by several researchers for the seasonal and diurnal oscillations of subsurface radon concentrations, show correlations between this gas and atmospheric temperature. Radon concentrations were highest during heatwaves lasting several days and exhibited seasonal trends (winter and summer). Since 1900, radon has been widely studied including for its impact on human health, because inhalation of radon is the largest source of exposure to ionizing radiation for the world's population, contributing more than 40% to the effective dose of environmental radioativity.

However, the literature is poor in the correlation between environmental radioativity and respiratory diseases. This work is assumed in the insular context of the Azores - Portugal. The base information (epidemiological and environmental radioativity) used in this work corresponds to daily data from 2010 to 2020 and provided by the Statistics Service of the Hospital da Horta (Açores) and The Network for the Continuous Surveillance of Radioactivity in the Environment, with a fixed station in Ponta Delgada (São Miguel_Azores), whose management being the responsibility of the Portuguese Environment Agency.

With the selected data, monthly averages were calculated and a statistical analysis was performed using the SPSS software (Statistical Package for the Social Sciences) version 28 for Windows. The null hypothesis (H0)_ “there is no correlation between environmental radioativity levels and the number of hospitalized individuals by respiratory diseases”. The alternative hypothesis (Ha)_”there is a correlation between environmental radioativity levels and the number of hospitalized individuals by respiratory diseases” was formulated. The level of significance (α) to accept or reject the null hypothesis was fixed a α ≤ 0.05. Pearson's correlation coefficient was used for inferential statistics. It was obtained, r =0.486 and p < 0.001, being r the Pearson correlation coefficient and p the p_value. It was found that p < α, therefore, the null hypothesis was rejected with a confidence level of 95%.

The correlation between environmental radioativity levels and the value of the monthly averages of respiratory pathologies is statistically significant, positive and moderate (r = 0.486, p < 0.001). Thus, as environmental levels of environmental radioativity increase, also the number of pacients with respiratory pathologies increase. The practical study’s conclusions show an interesting relationship between hospitalization patterns and environmental radioativity levels.

How to cite: Meirelles, M. and Helena, V.: Effect of Temperature and Environmental Radioactivity on Respiratory Diseases, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10265, https://doi.org/10.5194/egusphere-egu23-10265, 2023.

Posters on site: Fri, 28 Apr, 10:45–12:30 | Hall X4

Chairpersons: Alessandra Sciarra, Livio Ruggiero, Eleonora Benà
X4.75
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EGU23-1604
Livio Ruggiero, Alessandra Sciarra, Paola Tuccimei, Gianfranco Galli, Adriano Mazzini, Claudio Mazzoli, Maria Chiara Tartarello, Fabio Florindo, Gary Wilson, Martina Mattia, Laura Tositti, Pietro Morozzi, Eleonora Benà, Sabina Bigi, Raffaele Sassi, Jacob Anderson, and Giancarlo Ciotoli

Warming global climate threatens the stability of the polar regions and may result in cascading broad impacts. Studies conducted on permafrost in the Arctic regions indicate that these areas may store almost twice the carbon currently present in the atmosphere. Therefore, permafrost thawing has the potential to magnify the warming effect by doubling the more direct anthropogenic impact from burning of fossil fuels, agriculture and changes in land use. Permafrost thawing may also intensify the Rn transport due to the increase of fluid saturation and permeability of the soil. A detailed study of 222Rn and 220Rn activity levels in polar soils constitutes a starting point to investigate gas migration processes as a function of the thawing permafrost. Although several studies have been carried out in the Arctic regions, there is little data available from the Southern Hemisphere. The Italian – New Zealand “SENECA” project aims to fill this gap and to provide the first evaluations of gas concentrations and emissions from permafrost and/or thawed shallow strata of the Taylor Valley, Antarctica. Taylor Valley is one of the few Antarctic regions that are not covered by ice and therefore is an ideal target for permafrost investigations. Results from our field measurements highlight very low values for 222Rn and higher values for 220Rn, suggesting a shallow source. Usually the measured 222Rn activity values are controlled by the radionuclide content in the soil, the temperature of the soil, the porosity of the soil, and the water content. We applied the Akerblom formula to calculate the radon at equilibrium with the activity concentration of the 226Ra on the collected soil samples, and the presence of 222Rn amounts higher than those naturally produced by the outcropping sediments is detected. These results demonstrate the presence of preferential gas pathways through the permafrost from a deep source. It is the first time that this type of study has been performed in Antarctica and can make a significant contribution to understanding the melting permafrost processes and its implications for the environment. This dataset also represents an important benchmark for future measurements to track the melt progress of Antarctic permafrost.

How to cite: Ruggiero, L., Sciarra, A., Tuccimei, P., Galli, G., Mazzini, A., Mazzoli, C., Tartarello, M. C., Florindo, F., Wilson, G., Mattia, M., Tositti, L., Morozzi, P., Benà, E., Bigi, S., Sassi, R., Anderson, J., and Ciotoli, G.: Study of the origin of soil 222Rn and 220Rn activities in Taylor Valley, Antarctica., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1604, https://doi.org/10.5194/egusphere-egu23-1604, 2023.

X4.76
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EGU23-4985
David Benavente, Concepción Pla, María Candela Ruiz, Sara Gil-Oncina, Noé García-Martínez, Juan Carlos Cañaveras, Soledad Cuezva, Angel Fernández-Cortés, and Sergio Sánchez-Moral

In poor-ventilated caves, indoor gases can seasonally reach concentrations much higher than normal atmospheric values, which may become a critical health risk. In this study, we investigate the cave atmosphere of the Rull cave in terms of assessing the cave air quality and understanding the cave dynamics. Rull cave is located in Vall d’Ebo (Alicante, southeast Spain). It is a karstic cave developed in massive Miocene conglomerates and Cretaceous limestones. Above the cave, the silty-silty loam soil profile has a thickness below 1 m. Inside the cave, calcite speleothems and cave sediments are widely present. The uranium and thorium concentrations are higher for the soil and cave sediments, and minor for host-rock, and lower for speleothems. Moreover, both soil and cave sediments are powder materials, and the emanation is enhanced in comparison to host-rock and speleothems, although their volume in the cave is higher than soil and cave sediments.

At the cave location and for a decade-long monitoring period (November 2012 - July 2022), the prevailing meteorological conditions in terms of temperature and relative humidity were 16.1 ºC and 69.9%, respectively, on daily average values. The average annual precipitation is 553 mm. In the cave interior and besides the presence of visitors (15000 visitors/year), mean temperature (16.2 °C) and relative humidity (97.6%) maintain stable values.

In an annual cycle, the cave presents two different gaseous stages (stagnation and ventilation). Maximum average values of CO2 and 222Rn concentration (3966 ppm and 4185 Bq/m3) are reached within the stagnation stage (April/May to September). On the contrary, in the ventilation stage (October to March/April) the cave reaches the lowest concentrations in its inner atmosphere (478 ppm and 404 Bq/m3).

The spatial distribution of gases in the cave is dependent on the air density gradient between the cave and the outer atmosphere and controls the seasonal variations of both gases. The emanation of 222Rn from cave sediments, host-rock, and speleothems, contributes to increasing and maintaining a nearly 222Rn cave concentration during the stagnation stage. Dripping water degassing might also contribute to raising gas concentrations in caves. However, in Rull cave dripping waters are not abundant and thus the contribution of CO2 or 222Rn degassing from seepage waters to increase cave gaseous concentration might be low.

The continuous monitoring of Rull cave provides substantial information about the environmental situation of the cave atmosphere in terms of air quality for visitors and cave guides. The maximum average concentrations of CO2 and 222Rn in Rull cave and exposition times and doses comply with the recommendations of the legislation. Considering 222Rn, accurate planning of the cave guides and visitors during the stagnation stage is recommended to be less exposed to ionizing radiation due to the presence of radon gas.

How to cite: Benavente, D., Pla, C., Ruiz, M. C., Gil-Oncina, S., García-Martínez, N., Cañaveras, J. C., Cuezva, S., Fernández-Cortés, A., and Sánchez-Moral, S.: Radon dynamic and air quality in the Rull cave (southeast Spain), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4985, https://doi.org/10.5194/egusphere-egu23-4985, 2023.

X4.77
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EGU23-1593
Alessandra Sciarra, Luca Pizzino, Livio Ruggiero, Gianfranco Galli, Tullio Ricci, Giancarlo Ciotoli, Rosella Nave, Stefano Graziani, Stanley E. Beaubien, and Sabina Bigi

Radon is a natural radioactive gas produced by the decay of its parent nuclide in bearing rocks and soils. Inhalation of radon gas poses a serious risk for human health and the World Health Organization stated the doubtless correlation between long exposure to radon gas and lung cancer. In this context, 76 indoor radon measurements in private and public buildings were performed in the Ciampino municipality. This study was carried out within the framework of the LIFE-Respire project. Indoor radon concentration was measured by using passive nuclear track detectors (CR-39) and analysed using RADOSYS system at INGV Radionuclides laboratory. Measurements were carried out in winter and summer seasons to assess the range of seasonal fluctuations, as recognised elsewhere. Results show a substantial increase of maximum indoor values in winter (up to 1575 Bq/m3) that are two times higher than those measured in the summer period (up to 764 Bq/m3). The annual mean and median values (283 and 203 Bq/m3, respectively) are both below the EU recommended limit of 300 Bq/m3.

Moreover, a questionnaire on radon risk perception was designed for the specific context of the LIFE-Respire project and distributed in a sample of residents and students in the Municipality of Ciampino to measure, among many other aspects, the salience of the hazard, knowledge of the hazard and of hazard mitigation strategies, perceived preparedness of and trust in officials, sources of received information and preferred methods of receiving information, and the level of interest in the project approach (including remediation measures).

How to cite: Sciarra, A., Pizzino, L., Ruggiero, L., Galli, G., Ricci, T., Ciotoli, G., Nave, R., Graziani, S., Beaubien, S. E., and Bigi, S.: Indoor Radon Measurements in public and private buildings in the Ciampino municipality and its risk perception assessment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1593, https://doi.org/10.5194/egusphere-egu23-1593, 2023.

X4.78
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EGU23-12456
Gaia Soldati, Maria Grazia Ciaccio, Antonio Piersanti, Valentina Cannelli, and Gianfranco Galli

The primary stone building material of ancient Rome from its initial settlement until recent times is constituted by the tuff; easy to cut, resistant to weathering, and an effective thermal insulator, with the disadvantage of a significant radionuclide content. An accurate monitoring of indoor radon in workplaces and residential dwellings constitutes a first step towards mitigating the exposure to the population. Since radon diffusion dynamics involves complex interactions among many environmental parameters on different time scales, a proper assessment of radon concentration variations can be better achieved by means of active monitoring approaches. We present here the results of continuous measurements conducted in 35 residential dwellings located in the municipality of Rome and its suburban area, and in a public building and workplace: the geophysical museum of Rocca di Papa.
The use of active devices makes it possible to discriminate between average indoor radon measured during the day, when workers and visitors are more likely present, and overnight, more relevant for the exposure of residents. Collecting long time series of radon concentration enables us to identify fluctuations over seasonal scales, with radon generally decreasing in the warm season. The simultaneous tracking of different floors of the same building shows an inversion of the dynamics of gas convection during the warm season compared to the cold one, likely depending on the chimney effect. Monitoring different rooms of the same dwelling reveals that values of gas concentration may greatly differ, indicating the importance of ventilation and/or heating system. Considering several dwellings allows us to question the general belief of a constantly higher exposure of the lowest floors to the indoor radon risk with respect to elevated floors (radon would enter mainly through foundation walls). Finally, the clustering of houses with high indoor radon levels in the historic center of Rome indicates the influence of geogenic radon and of building characteristics like age, typology, and construction materials.
With so many endogenous and exogenous factors affecting the healthiness of indoor environments in terms of radon concentration, a proper assessment of health hazard requires the knowledge of the dynamics of the gas generation and transport inside the buildings, and of its temporal fluctuations; our analysis provides the instruments to disclose the characteristics of such dynamics, with the final goal to select the most suitable preventive measures to reduce radon exposure. 

How to cite: Soldati, G., Ciaccio, M. G., Piersanti, A., Cannelli, V., and Galli, G.: Radon risk mitigation in urban environments: experiences from active monitoring, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12456, https://doi.org/10.5194/egusphere-egu23-12456, 2023.

X4.79
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EGU23-7476
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ECS
Eleonora Benà, Giancarlo Ciotoli, Livio Ruggiero, Eric Petermann, Peter Bossew, Claudio Mazzoli, Luca Verdi, and Raffaele Sassi

Radon (222Rn) is a radioactive gas considered the major source of ionizing radiation exposure for the population and several epidemiological studies provided evidence of its detrimental effects on human health. As a consequence, the World Health Organization classified this gas as the second cause of lung cancer after cigarettes smoking. A significant fraction of lung cancer can be attributed to the indoor Rn exposure, i.e. houses and workplace. In particular, Indoor Radon Concentration (IRC) is the product of the Geogenic Radon Potential (GRP), conceptualised as the contribution of Rn released by the Earth. Therefore, in the characterisation of the potential risk over an area is fundamental considering the geological constraints under the dwellings, the building styles and living habits. In Europe, the Basic Safety Standards Directive 2013/59/EURATOM aims to reduce the human exposure to Rn in houses and workplace, on the one hand fixing some reference values, on the other hand requiring to the European states to delineate the Radon Priority Areas (RPA), i.e. that areas where IRC exceed the European Directive reference value. In particular, mapping the GRP as an indicator of the Rn related hazard is fundamental for: (i) delineate the RPAs through the quantification of geogenic Rn, that can potentially influx within buildings; (ii) understand how GRP can affect the vulnerability over an area thus contributing to the Rn risk. In this study, we focused on mapping the GRP of a specific study area located in the Pusteria Valley (Bolzano province, eastern Italy). This area is well-known from a geological and structural point of view and it is characterised by a wide non-seismically active fault zone showing a very high gas permeability.  In particular, we have applied a machine learning technique (i.e. Forest Regression), to construct a high resolution (50 m*50 m) GRP map of the study area considering several proxy variables related to the Rn sources (e.g., radionuclide content in rocks), to the Tectonically Enhanced Radon (TER) quantity and to the exhalation process towards the atmosphere. Furthermore, we have assessed the vulnerability of the area by introducing the location of inhabited areas to provide a preliminary map of RPAs. Results show that dwellings characterised by high vulnerability are located in the area with the highest GRP. This work represents the first attempt in Italy to define the RPAs.

How to cite: Benà, E., Ciotoli, G., Ruggiero, L., Petermann, E., Bossew, P., Mazzoli, C., Verdi, L., and Sassi, R.: Mapping the Geogenic Radon Potential as a first step to define the Radon Priority Areas, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7476, https://doi.org/10.5194/egusphere-egu23-7476, 2023.

X4.80
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EGU23-6423
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ECS
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Highlight
Eric Petermann, Peter Bossew, Nils Suhr, and Bernd Hoffmann

Accurate knowledge of indoor radon exposure is vital information for assessing radon-induced health effects, identifying radon prone areas or estimating the number of people affected by the exceedance of a specific radon concentration in a given area.

Large-scale measurement campaigns are usually the tool of choice for determining regional or national indoor radon exposure. These campaigns need to be representative in terms of all relevant factors governing indoor radon exposure (e.g., geogenic radon availability, distribution of people across floor levels, building types) for providing an unbiased estimate. In practice, creating a fully representative sample of the population is hardly achievable due to the multitude of relevant factors which cannot be fully controlled by sampling design. Further, estimating indoor radon exposure at a high spatial resolution (district or municipality scale) requires a large number of measurements which increases the financial and logistic effort dramatically. Therefore, predictive models are widely applied as a complementary tool for exposure assessment by utilizing available information on the relevant variables that determine indoor radon. However, these models are usually only able to explain a certain amount of the observed variability due to the absence of some relevant information (building-specific data on air tightness, ventilation rates etc.). As a consequence, model-based assessments tend to underestimate the true variability of indoor radon. 

In this study, we present a probabilistic approach that overcomes this shortcoming and intends to give a more realistic estimate of the true indoor radon distribution at several spatial resolutions. Our approach consists of the following steps:

1) fitting a random forest model utilizing 12 predictors to ~14,000 full-year indoor radon measurements in residential buildings in Germany;

2) predicting a range of quantiles of the expected indoor radon distribution for each floor level of each German residential building;

3) fitting a lognormal distribution to the estimated quantile data to approximate the building and floor level specific probability density function (PDF);

4) random sampling from this PDF with a sample size proportional to the population distribution;

5) aggregating results on several spatial scales. 

The benefits of this approach are 1) to allow an accurate exposure assessment even if surveys were not fully representative concerning the main controlling factors by utilizing high-resolution information on the spatial distribution of these factors via predictive models. 2) with a given amount of measurements, exposure distribution can be estimated at a much higher spatial resolution compared to basic aggregate statistics.  

How to cite: Petermann, E., Bossew, P., Suhr, N., and Hoffmann, B.: Estimating national indoor radon exposure at a high spatial resolution – improvements by a machine learning based probabilistic approach, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6423, https://doi.org/10.5194/egusphere-egu23-6423, 2023.

X4.81
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EGU23-7114
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ECS
Alexandra Kölbl and Michael Blaschek

Radon (222Rn) is a radioactive gas of the uranium-radium decay chain and occurs naturally in soil air. Primarily by diffusion, radon migrates to the surface and can accumulate in buildings, where it is harmful to human health because of its radioactivity. To tackle this particular health hazard, radon mitigation was recently introduced into national law. Among other things, the law demanded the designation of radon priority areas by the end of 2020. These areas are defined as administrative areas with a large proportion of land affected by high radon concentrations inside buildings. In the state of Baden-Wuerttemberg these areas were selected at municipality level based on a 10x10 km national map of geogenic radon potential (GRP) provided by the German Federal Office for Radiation Protection (BfS) accompanied by a state-specific map of uranium concentrations. With the prospect of future designations, this work aims at replacing the national GRP map used in 2020 by a more sophisticated state-specific version. In doing so, we improve spatial resolution, focus on covariates that only represent the state-relevant features of geology and soil and move away from a kriging-based mapping approach towards machine learning.

This ongoing study is currently based on 580 radon measurements in soil gas at 1 m depth from different surveys spread irregularly over Baden-Wuerttemberg in southeast Germany. This point dataset is combined with a set of covariates from factors that influence radon concentrations such as soil parameters, geology, relief, climate and a map of uranium concentrations created from over 4000 heavy metal measurements. Modelling is done using a random forest (RF) approach as implemented in the R packages ranger and mlr3. Preliminary results indicate that the new GRP map with a spatial resolution of 250 m is highly useful in classifying communities as vulnerable areas, which were previously not called due to uncertain underlying data. In addition, model output confirms up to 80 % of already identified radon priority areas.

Machine learning algorithms such as RF with its precise learning progressions can be used to create GRP maps at regional scale at high resolution. Besides further improving the RF model, next steps will focus on explainable machine learning, i.e. to produce features that support policy makers in finding acceptance by the public in sight of a sensitive topic. This includes variable importance plots, uncertainty measures and maps representing areas of applicability. The latter will also be used to help guiding the ongoing radon measurement programme of Baden-Wuerttemberg, which currently comprises approximately 100 new locations per year.

How to cite: Kölbl, A. and Blaschek, M.: Identifying radon priority areas by mapping geogenic radon potential of soils in Baden-Wuerttemberg (Germany) using machine learning algorithms, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7114, https://doi.org/10.5194/egusphere-egu23-7114, 2023.

Posters virtual: Fri, 28 Apr, 10:45–12:30 | vHall NH

Chairpersons: Eric Petermann, Eleonora Benà, Livio Ruggiero
vNH.29
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EGU23-12769
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ECS
Linda Bonorino, Gianluca Beccaris, Paola Bisi, Paolo Chiozzi, Andrea Cogorno, Elga Filippi, Riccardo Narizzano, Sonja Prandi, and Massimo Verdoya

Radiometric surveys are used to investigate different scientific and practical issues in Earth’s science studies, ranging from basic geophysics to mineral exploration and natural radiation monitoring. The latter is a topic of growing interest. 238U, 232Th and 40K, which occur in variable quantities in the Earth’s crust rocks, are the primary cause of natural, potentially hazardous, gamma-ray exposure. Another important environmental aspect of natural radioactivity regards the effects of  222Rn resulting from the 238U decay. This paper proposes an experimental approach to investigate the relationship between uranium and indoor radon concentration. We combined ground gamma-spectrometry with alpha-track detector measurements. We tested this methodology in the Alpine geological units of western Liguria (Italy). This area is densely populated and characterised by various lithotypes, spanning from sedimentary to metasedimentary and metavolcanic rocks. The latter are known for their abundance of natural radionuclides. Due to the width of the surveyed area (408 km2), we carried out about 300 gamma-ray determinations on the more extensive geological formations, with particular reference to those hosting the main residential areas, together with about 130 measurements of indoor radon. By considering the nineteenth percentile of the recorded specific activity, the largest value of 238U was 93 Bq/kg. It was found in the more acid metamorphic rocks (metarhyolites and porphyric schists) where we carried out also the largest number of gamma-ray spectrometry measurements. In the metasedimentary rocks, the largest activities of 238U were observed in quartzschists and micaschists (89 Bq/kg). In the sedimentary lithotypes, specific activities are generally lower than 40 Bq/kg. We found that the number of buildings with 222Rn exceeding 200 Bq/m3 increases where the specific activity of 238U is larger. About 40% of dwellings and public buildings with 222Rn>200 Bq/m3 occurs in the lithotypes (metarhyolites and micaschists) with 238U>60 Bq/kg. A comparison between the indoor 222Rn concentration and the 238U specific activity measured on the same geological formation showed a linear correlation. Using the records of 238U specific activity, we developed a map of the expected radon concentration on the different geological formations of the surveyed area. Despite the limitations and uncertainties, mainly related to the uneven data coverage and the complex interaction between the building and the bedrock, the proposed approach showed that gamma-ray spectrometry can be a valuable tool to identify areas of more significant potential risk of radon emanation.

How to cite: Bonorino, L., Beccaris, G., Bisi, P., Chiozzi, P., Cogorno, A., Filippi, E., Narizzano, R., Prandi, S., and Verdoya, M.: An approach to relate uranium to indoor radon: a case study from the western Ligurian Alps (Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12769, https://doi.org/10.5194/egusphere-egu23-12769, 2023.