Indoor radon in Spanish workplaces. A pilot study before the introduction of the European Directive 2013/59/Euratom

To explore whether there is a possible problem regarding indoor radon concentration surpassing the new European Directive 2013/59/Euratom threshold in Spanish workplaces. We also aim to find out whether radon concentration might be associated with certain characteristics of workplaces.

We performed a cross-sectional study to measure indoor radon concentrations in Spanish workplaces including five different sectors (education, public administration, the health sector, the tourist sector and the private sector). To be measured, the workplace should be occupied permanently by at least one worker. Alpha-track type radon detectors were placed for at least three months and read at the Galician Radon Laboratory at the University of Santiago de Compostela. A descriptive analysis was performed on radon distribution by sector, building characteristics and number of workers affected.

We faced enormous difficulties in finding volunteers for this study. Galicia and Madrid had the highest number of measurements. Of a total of 248 measurements, 27% had concentrations above 300 Bq/m³. Median radon concentration was 251 Bq/m³ in Galicia, followed by Madrid, with 61.5 Bq/m³. Forty-six percent of the workplaces measured in Galicia had radon concentrations higher than 300 Bq/m³ followed by 10.6% in Madrid. Nineteen percent of all workers were exposed to more than 300 Bq/m³ and 6.3% were exposed to radon concentrations higher than 500 Bq/m³.

Indoor radon exposure might be a relevant problem in Spanish workplaces and the number of affected workers could be high. The prevalence of workers exposed to high radon concentrations probably depends on the geographical area.