The results show that the annual average concentrations of ~(222)Rn,~(220)Rn and ~(220)RnD in two mines were 292 and(4 919) Bqm~(-3),91 and 2 638 Bqm~(-3),0.9 and 6.0 EEC Bqm~(-3),respectively.

• 测量结果表明；史家营煤矿的222Rn、220Rn年平均浓度和220Rn平衡当量浓度分别为292、90.；5和0