Characteristics and temporal variation of airborne radon decay progeny in the indoor environment in Catalonia (Spain)

It is well known that the radioactive dose due to radon progeny indoors depends mainly on the radon exhalation rate and other parameters such as the equilibrium factor (F), unattached fraction (f(p)), and particle size distribution. These parameters vary widely from one site to another and with time, according to the characteristics of the site and the climate. This paper summarizes the work carried out in the Spanish region of Catalonia and is a report gn the preliminary results of an ongoing study. Four sites were selected according to their characteristics and radon concentration levels. in one of the dwellings, a three-floor house, radon concentration ranging from 10 Bq/m(3) to more than 3500 Bq/m(3), was found in a set of continuous measurements taken over a period of 90 d. In this house, it was found that the advection form of radon exhalation, through the toilet drain pipe, depended mainly on temperature and wind variations. Parameters, such as F (0.02-0.65) and f(p) (0-0.70) and particle size distributions, were determined continuously. Average effective dose per unit exposure to radon, during periods of 3 d at least, vary widely between the different dwellings, from 5.4 nSv per Bq m(-3) h to 15.6 nSv per Bq m(-3) h and may vary in a ratio of more than 8 in the same dwelling. Copyright 1996 Elsevier Science Ltd.