Radon behavior investigation based on cluster analysis and atmospheric modelling

Abstract

Radon measurements were performed in Huelva, a city located near a phosphogypsum repository in the SW of the Iberian Peninsula, between March 2015 and March 2016. The mean values of this gas oscillate between 5.6 and 10.9 Bq m −3 and maximum ranges between 36.4 and 53.4 Bq m −3 . Radon shows the expected monthly variation with higher levels in November and December. Typical daily evolutions were also observed, with maximum between 06:00 and 08:00 UTC (Coordinated Universal Time) and minimum around noon. To extract daily radon patterns, the cluster technique of K-means was applied. Based on this classification, four different case study periods were analyzed in detail, describing two events with high radon levels and two with low radon. Local meteorology, back-trajectories computed with the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model and meteorological fields from the WRF (Weather Research and Forecasting) model, were used to analyze the four case study periods selected. Low radon periods are characterized by the occurrence of non-pure breezes and maritime air masses from the Atlantic Ocean, whereas high radon periods occur under pure sea-land breezes affected by Mediterranean air masses. Factors such as meteorology or local emission sources alone may not be enough to explain the high radon events in the area. Other factors could be playing a major role in the radon levels. The obtained results indicate the contribution of radon transported from medium-long range, suggesting that, under specific weather conditions, the Gulf of Cadiz could act as a radon trap and the continental areas around the Western Mediterranean Basin could act as a radon source.

Inter-comparison study of atmospheric <sup>222</sup>Rn and <sup>222</sup>Rn progeny monitors

“…Stockburger and Sittkus, 1966;Polian, 1986;Paatero et al, 1998;Levin et al, 2002), which sample and measure aerosol-bound radon progeny. Finally, a third method is being used at several Spanish atmospheric stations (Vargas et al, 2015;Hernández-Ceballos et al, 2015;Grossi et al, 2016;Frank et al, 2016;Grossi et al, 2018;Gutiérrez-Álvarez et al, 2019). This type of instrument performs a direct measurement of 222 Rn and 220 Rn (thoron) activity concentrations using electrostatic deposition of 218 Po and 216 Po, respectively (Hopke, 1989;Grossi et al, 2012).…”

Full characterization and calibration of a transfer standard monitor for atmospheric radon and thoron measurements

“…(Schmithüsen et al, 2017); ii) the monitor from the Australian Nuclear Science and Technology Organisation (ANSTO), which determines the atmospheric 222 Rn activity concentration using dual-flow-loop two-filter method (Whittlestone and Zahorowski, 1998;Zahorowski et al, 2004); iii) the Atmospheric Radon MONitor (ARMON), designed and built at the Institute of Energy Technologies (INTE) of the Universitat Politècnica de Catalunya (UPC), which is based on alpha spectrometry from the positive ions of 218 Po electrostatically collected on a Passivated Implanted Planar Silicon (PIPS) 65 detector surface (Grossi et al, 2012;Vargas et al, 2004Vargas et al, , 2015. Several monitors of this last type have been displaced at atmospheric Spanish stations for atmospheric research studies (Grossi, 2012;Hernández-Ceballos et al, 2015;Vargas et al, 2015;Grossi et al, 2018;Gutiérrez-Álvarez et al, 2019). The response of the ARMON under different field conditions was also compared with the ones from other previously cited research instruments in the south of Paris in 2016 (Grossi et al, 2020).…”