Bronchial Rn dose survey for residences

The bronchial dosimeter for Rn progeny proposed by Yu and Guan in 1998 was employed to survey the bronchial dose from Rn progeny in 30 residences in H ong Kong, An average bronchial deposition fraction of Rn progeny was obtain ed as 0.0334, which gave an average dose conversion factor (DCF) of 8.5 mSv WLM (-1). The mean values of potential x energy concentration (PAEC) depos ited in the tracheobronchial region (PAEC(T-B)) total PAEC in air (PAEC(T)) , annual effective dose (E), concentration of Rn gas (RC) and annual dose c onversion factor (ADCF) for all the residential sites combined were 0.11+/- 0.05, 3.1 +/- 1.4 mWL, 1.2 +/- 0.5 mSv yr(-1), 23 +/- 10 Bq m (-3) and 0.05 5 +/- 0.020 (mSv yr (-1) per Bqm (-3)), respectively, with air-conditioned sites (AC sites) and non-AC sites having significantly different mean ADCF values. The indoor relative humidity affected PAECT and RC with high confid ence levels (> 95%). (C) 2001 Elsevier Science Ltd. All rights reserved.