Ennemoser O, Oberdorfer E, Brunner P, Schneider P, Purtscheller F, Stingl V, Ambach W
Institute of Medical Physics, University of Innsbruck, Austria.
Health Phys. 1995 Aug;69(2):227-32. doi: 10.1097/00004032-199508000-00007.
In an area of unusually high indoor radon concentrations of up to 270,000 Bq m-3, four houses were selected for mitigation of indoor radon. Methods used were basement sealing, soil depressurization, a mechanical intake and outlet ventilation system with heat exchanger in the basement, and a multilayer floor construction using a fan to suck radon from a layer between bottom slab and floor. Basement sealing proved unsuccessful, the radon concentration remained unchanged after the mitigation attempt. The most successful remedial measure was soil depressurization using two fans and loops of drainage tubes to withdraw radon from the region under the floor and outside the walls of the basement and from soil under the part of the house without a basement. This method reduced the basement radon level in winter by about a factor of 200, i.e., from 100,000 Bq m-3 to 500 Bq m-3, and the ground-floor level by about a factor of 400. As regards the mechanical intake and outlet ventilation system with heat exchanger in the basement, it is essential to ensure that ventilation provides increased air pressure in the basement compared to outdoors. Unbalanced mechanical intake and outlet ventilation may decrease the air pressure indoors compared to outdoors, leading to increased radon concentrations. Optimization of this method reduced radon concentrations from 200,000 Bq m-3 to 2,000-3,000 Bq m-3 in winter. In one house with only a very small basement, a multilayer floor construction using a fan to suck radon from a layer between the bottom slab and floor was found to reduce radon concentrations on the ground floor from 25,000 Bq m-3 to about 1,700 Bq m-3 in winter. The results show that even in areas with extremely high radon concentrations, effective mitigation of indoor radon can be accomplished if suitable techniques are used. The evaluation of the different mitigation methods shows good coincidence with the ICRP 65 report.
在一个室内氡浓度异常高、高达270,000贝克勒尔每立方米的区域，挑选了四所房屋来减轻室内氡污染。所采用的方法包括地下室密封、土壤减压、地下室带有热交换器的机械进排气通风系统，以及使用风扇从底板和地板之间的一层抽取氡的多层地板构造。地下室密封被证明是不成功的，在减轻氡污染的尝试之后，氡浓度保持不变。最成功的补救措施是土壤减压，使用两个风扇和排水管道回路从地板下方区域、地下室墙壁外部以及房屋无地下室部分下方的土壤中抽取氡。这种方法在冬季将地下室氡水平降低了约200倍，即从100,000贝克勒尔每立方米降至500贝克勒尔每立方米，将一楼氡水平降低了约400倍。至于地下室带有热交换器的机械进排气通风系统，必须确保通风使地下室的气压高于室外。不平衡的机械进排气通风可能会使室内气压低于室外，导致氡浓度增加。对该方法进行优化后，在冬季将氡浓度从200,000贝克勒尔每立方米降至2,000 - 3,000贝克勒尔每立方米。在一所只有非常小地下室的房屋中，发现使用风扇从底板和地板之间的一层抽取氡的多层地板构造在冬季将一楼氡浓度从25,000贝克勒尔每立方米降至约1,700贝克勒尔每立方米。结果表明，即使在氡浓度极高的区域，如果使用合适的技术，也可以有效地减轻室内氡污染。对不同减轻氡污染方法的评估与国际辐射防护委员会第65号报告显示出良好的一致性。
