Radon (²²²Rn) and Thoron (²²⁰Rn), the members of Uranium and Thorium decay series respectively, are ubiquitous in nature. Being airborne alpha active radioisotopes, they are the major contributors of inhalation dose especially in the indoor environments. This study measures the Potential Alpha Energy Concentration (PAEC) of radon/thoron progenies in the dwellings of Eloor industrial region in Kerala and thereby evaluate the internal/inhalation dose to the population. Aerosol samples were collected from 100 locations in the study area using high volume air sampler and gross particulate activity measurement was done using ZnS(Ag) alpha counter. The PAEC of radon progeny in the study area varied from 0.13 to 2.94 and that of thoron progeny varied from 0.3 to 7.7. It has been observed that the dwelling with marble floor possesses relatively higher concentration of radon and thoron progenies while lower concentrations were observed in dwellings with tile floors. Taking the mean concentrations of ²²²Rn and ²²⁰Rn progeny levels of 100 samples collected, the inhalation dose was 0.14 mSvy^-1 for radon and 0.09 mSv y^-1 for thoron, which delivers a total inhalation dose of 0.23 mSv y^-1 to the population residing in that area. Measured data show below compared to the ICRP recommended action level of 3–10 mSvy^-1 for general populace. Although measured data requires no immediate action to reduce the hazardous radon and thoron level in the studied area, however the radiation risk from such hazardous gas is not completely discarded. Since human spent more than 80% of time in indoor and the radiation hazards follows linear no threshold model, therefore the indoor environment should be well ventilated to reduce any unexpected health hazards.

氡 ( ²²² Rn) 和钍 ( ²²⁰⁾Rn)，分别是铀和钍衰变系列的成员，在自然界中无处不在。作为空气传播的 α 活性放射性同位素，它们是吸入剂量的主要贡献者，尤其是在室内环境中。这项研究测量了喀拉拉邦 Eloor 工业区住宅中氡/钍后代的潜在阿尔法能量浓度 (PAEC)，从而评估了人口的内部/吸入剂量。使用大容量空气采样器从研究区域的 100 个位置收集气溶胶样品，并使用 ZnS(Ag) α 计数器进行总颗粒活性测量。研究区氡子代PAEC为0.13~2.94，钍气子代PAEC为0.3~7.7。据观察，大理石地板的住宅具有相对较高的氡和钍后代浓度，而在瓷砖地板的住宅中观察到的浓度较低。取平均浓度²²² Rn和^220级的收集的100个样品Rn中子代水平，吸入剂量为0.14 mSvy ^-1氡和0.09毫ÿ ^-1为钍，可提供0.23毫y的总吸入剂量^-1的人口居住在那个区域. 测量数据如下所示，与 ICRP 建议的行动水平 3–10 mSvy ^{-1 相比}对于普通民众。虽然测量数据不需要立即采取行动来降低研究区域中危险的氡和钍气水平，但是并没有完全消除此类危险气体的辐射风险。由于人类80%以上的时间在室内，辐射危害遵循线性无阈值模型，因此室内环境应保持良好的通风，以减少意外的健康危害。