First results of measurement of equilibrium factors F and unattached fractions f_p of radon progeny in Czech dwellings

摘要

The unattached fraction of radon decay product clusters f_p and equilibrium factor F are dose relevant parameters in all dosimetric approaches to dose calculation. In the past, three year continuous weekly measurements of unattached and attached activity of radon daughter product and air exchange rate were carried out during heating season in 30 occupied typical Czech family houses. The results indicated significantly different weekly averages of equilibrium factor F and f_p for houses located in towns compared those in villages. Due to this fact, approximately a 10% average increase of equivalent lung dose rate was estimated in the detriment in towns. Average values of equilibrium factor F and f_p were 0.40 and 8.6% in urban houses and 0.32 and 10.7%, respectively in rural houses. Based on the measurements of mean values of f_p, average effective dose conversion factors (DFC) in units of mSv per working level month (WLM) were estimated to be 15.0 mSv/WLM in urban houses and 15.9 mSv/WLM in rural houses, respectively.