Effects of air conditioning, dehumidification and natural ventilation on indoor concentrations of Rn-222 and Rn-220

A bedroom was selected for detailed measurements on Rn-220 and Rn-222 conce ntrations and environmental parameters including CO2 concentration, tempera ture and relative humidity. To simulate different sealing conditions, five conditions were artificially created in the sampling period of 25 consecuti ve days. It was concluded that natural Ventilation is the most efficient wa y to lower the Rn-222 levels, while air conditioning is the next. Dehumidif ication provides only a marginal reduction of Rn-222 levels. The Rn-220 con centrations are not affected by natural ventilation, air conditioner or deh umidification, and were ail around 10 Bq m(-3). There are no significant co rrelations between the Rn-220 and Rn-222 concentrations and environmental c onditions such as CO, concentrations, temperature, relative humidity and pr essure. (C) 1999 Elsevier Science Ltd. All rights reserved.