Institute of Industrial Ecology UB RAS, Ekaterinburg, Russia.
Radiat Prot Dosimetry. 2020 Nov 27;191(2):150-153. doi: 10.1093/rpd/ncaa154.
Classical aerosol physics predicts that it is impossible to observe noticeable values of the unattached fraction of decay products of thoron at typical concentrations of aerosol particles. The experimental data have shown that the unattached fraction of the thoron decay products in a monazite storage facility is in the range 0.3-0.6. This effect is caused by local increase in air exchange near the inlet of the sampling device at high 220Rn concentrations. It was found that a dynamic shift between the unattached and attached thoron decay products is also observed in the worker's breathing zone at a high concentration of thoron. The 212Pb unattached fraction in worker's breathing zone was ~0.4. It demonstrates that when evaluating inhalation exposure to the products of the decay of thoron, it is necessary to take into account the increase of the 212Pb unattached fraction in the worker's breathing zone.
经典气溶胶物理学预测，在气溶胶粒子的典型浓度下，观察到钍射气衰变产物的非结合部分的显著值是不可能的。实验数据表明，在独居石储存设施中，钍射气衰变产物的非结合部分在 0.3-0.6 范围内。这种效应是由于在高 220Rn 浓度下，采样装置入口附近的空气交换局部增加所致。还发现，在高浓度钍的情况下，工人呼吸区的钍射气衰变产物的非结合部分和结合部分之间也存在动态转移。工人呼吸区的 212Pb 非结合部分约为 0.4。这表明，在评估吸入钍衰变产物的暴露时，有必要考虑工人呼吸区 212Pb 非结合部分的增加。
