Rn concentrations and the radiation exposure levels in the Nerja Cave

²²²Rn concentrations in the air in one sampling point located in Nerja Cave (Spain) () have been measured over one year, since July 2003–June 2004. ²²²Rn levels were continuously monitored using Alpha-Guard (Genitron instruments) equipment, model PQ2000PRO. Firstly, the aim of this study was to perceive the daily, monthly and seasonal variations patterns of ²²²Rn concentrations. Diurnal cycles are presented by season showing that the ²²²Rn concentrations in spring–summer are higher than autumn–winter. The hourly variations are discussed in relation to various meteorological factors measured in the Cave and also on the outdoor. We have evaluated the radiation exposure levels for workers and tourists; those represent only a low percentage of the exposure guides for the general population ICRP, 1994. Protection against Radon-222 at home and at work. Pergamon Press, Oxford (publication 65).