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

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.