Radon mitigation by use of surface gas drainage system

The uranium mining was stopped in the Mecsek Mountains in 1997. Most of the dwelling houses, located close to a mine-tunnel, show a yearly average of indoor radon activity concentration higher than the EU recommendation for existing buildings (300 Bq/m3). To reduce the high radon concentration, new radon mitigation was completed in a selected house and the mitigation effect has been studied. Indoor radon concentration was monitored continuously for one month once before and three times after the mitigation technique was applied. Due to the mitigation, the initial radon concentration was decreased by 71% (average radon concentration before the mitigation: 1480±74 Bq/m3, after the mitigation: 420±33 Bq/m3). In the paper these results are interpreted from the point of view of functioning of the applied mitigation technique and dependence of the mitigation efficiency on the meteorological conditions.