中文摘要：

采用固体径迹探测器对珠海居民室内的钍射气浓度进行了测定。对每一个测定点在一年内分4个季度分别进行了测定,共获得96户居室测定结果,结果表明,钍射气浓度的变化范围为3～243Bq/m3,几何平均值为43Bq/m3,钍射气导致年有效剂量达0.37mSv;其中砖瓦结构、土面平房的室内钍射气浓度最高,导致浓度升高的原因是土壤中钍含量高;房间的通风对流可以将地面释放出来的钍射气带上来,从而导致室内钍射气浓度偏高。

英文摘要：

Thoron concentration levels were measured in the high background radiation area located in Zhuhai city using solid-state nuclear track detectors.Measurements were carried out quarterly at each location throughout a year.Totally 96dwellings were selected for the study.Thoron concentration is vary between 3-243Bq/m 3,with the geometric mean value being 43Bq/m 3 .The dwellings with tile configuration and earth floor have highest thoron concentration.Existence of high thorium content in the soil leads the high thoron values. Increasing ventilation rate inside the dwellings enhances inversion currents and lifts more thoron from the ground,which make the higher concentration of thoron in dwellings.