Experimental and theoretical study of radon levels and entry mechanisms ina Mediterranean climate house

An experimental study has been carried out in an inhabited single-family ho use. Radon concentration in the different rooms of the house and in its gar den soil has been measured with Nuclear Track Detectors. No high difference s of radon concentration have been observed between the different rooms of the house, so that the proximity of the room level to the soil seems not to affect the radon concentration. The annual radon concentration obtained in doors and in the soil has been respectively 35 Bq m(-3) and 24 kBq m(-3). S ince radon generation in the source, entry into indoor air and accumulation indoors depend on several parameters, the effect of a specific parameter o il indoor radon concentration is difficult to explain from the radon measur ements only. The RAGENA (RAdon Generation, ENtry and Accumulation indoors) model has been adapted to the room in the basement of the house. The mean r adon concentration values obtained with the model are compared to experimen tal results derived from measurements using Nuclear Track Detectors. The us e of the model, together with the experimental study, has allowed character ising radon sources, levels and entry mechanisms in the house. The concrete walls have been found to be the most relevant radon source, while the cont ribution of the soil is negligible in this case. The indoor radon level is given by the balance of the permanent exhalation from concrete and the remo val due to ventilation. The indoor radon levels are close to the average va lue for the Barcelona area which, ill turn, is close to the world averaged value.