Atmospheric 222Rn concentration and source term at El Arenosillo 100 m meteorological tower in southwest Spain

Abstract

222Rn concentration time series at 10 m and at 100 m have been measured hourly for one year at the meteorological station, El Arenosillo, on the Spanish southwest coast. A 222Rn flux characterization was also done. A seasonal analysis of atmospheric 222Rn concentration was performed and results for each season present evidence associated with the origin of air masses reaching the El Arenosillo station. An increase in 222Rn concentration was observed when the wind came from Morocco, the Sierra Morena and the Guadalquivir valley areas. On the other hand, a net 222Rn concentration decrease was found when the wind came from the Atlantic Ocean and the South of Portugal. Low 222Rn flux of 4 Bq m−2 h−1 was measured. This result makes this station a useful site for studies related to remote 222Rn source contributions because of low local 222Rn background. The measured annual average concentration of 222Rn gas at the El Arenosillo station is 3.51 ± 0.05 Bq m−3 at 10 m and 2.61 ± 0.05 Bq m−3 at 100 m.