Simultaneous measurements of radon, thoron and equilibrium equivalent concentrations in family house - single case study

Simultaneous indoor measurements of radon, thoron and equilibrium equivalent con centrations, by three different continuous radon monitors in real ambient conditions, were performed and compared during two weeks period. Radon concentrations varied from 153 Bqm?3 to 870 Bqm?3 with variations of thoron concentrations in the range (2.17-219) Bqm?3. Obtained arithmetic means of equilibrium equivalent radon and thoron concentrations were (130 ? 50) Bqm?3 and (23 ? 18) Bqm?3, respectively. The inter-comparison of active radon de vices was focused on consistency of results between them selves and the influence of environmental conditions on the behavior of each detector system. The obtained statistically significant correlation between the results of used monitors, validates them for application in radon diagnostic measurements as the first step in radon remediation and dose assessment.