Survey of the Rn dose conversion factor for offices

The Rn dose conversion factor (DCF), which relates the effective dose to th e exposure to the potential alpha energy concentration (PAEC) of inhaled Rn progeny, was surveyed for 23 occupied and air-conditioned offices in Hong Kong using the bronchial dosimeter for Rn progeny proposed by Yu and Guan i n 1998. The mean values of PAEC deposited in the tracheobronchial region (P AEC(T-B)), total PAEC in air (PAEC(T)) and the concentration of Rn (RC) for the offices were 0.13 +/- 0.12 mWL, 3.4 +/- 3.3 mWL and 30 +/- 12 Bq m(-3) , respectively, An average bronchial deposition fraction of Rn progeny was obtained as 0.037 (range: 0.033-0.051), which gave a DCF of 9.5 (range: 8.4 -13) mSv WLM-1. The annual effective dose (E) was estimated to be 0.38 +/- 0.35 mSv yr(-1) for the offices. (C) 2000 Elsevier Science Ltd. All rights reserved.