ABSTRACT Radon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon–thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31 ± 1 to 436 ± 12 Bq m–3, 4 ± 7 to 246 ± 5 Bq m–3, and 1.5 ± 0.9 to 13.1 ± 9.4 Bq m–3. The mean value of the equilibrium factor for thoron is estimated at 0.11 ± 0.16. The annual effective dose due to exposure to indoor radon and progeny ranges from 0.6 to 9 mSv a–1 with an average value of 2.6 ± 0.1 mSv a–1. The effective dose due to the exposure to thoron and progeny vary from 0.3 to 2.9 mSv a–1 with an average value of 1.0 ± 0.4 mSv a–1. The contribution of thoron and its progeny to the total inhalation dose ranges from 7 to 60 % with an average value of 26 %; thus their contributions should not be neglected in the inhalation dose assessment.

中文翻译：

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喀麦隆杜阿拉市室内氡和钍气的同时测量和吸入剂量评估

摘要 在喀麦隆杜阿拉市的 71 座住宅中进行了氡、钍和相关子代测量。氡-钍判别式探测器 (RADUET) 用于估计氡和钍浓度，而钍后代监测器测量平衡当量钍浓度 (EETC)。氡、钍气和钍气后代浓度从 31 ± 1 到 436 ± 12 Bq m–3、4 ± 7 到 246 ± 5 Bq m–3 和 1.5 ± 0.9 到 13.1 ± 9.4 Bq m–3 不等。钍气平衡因子的平均值估计为 0.11 ± 0.16。由于暴露于室内氡及其后代而导致的年有效剂量范围为 0.6 至 9 mSv a-1，平均值为 2.6 ± 0.1 mSv a-1。由于暴露于钍气和后代而产生的有效剂量从 0.3 到 2.9 mSv a–1 不等，平均值为 1.0 ± 0.4 mSv a–1。钍气及其后代对总吸入剂量的贡献范围为 7% 至 60%，平均值为 26%；因此，在吸入剂量评估中不应忽视它们的贡献。