Beta doses to cells possibly critical to human tumor formation from the beta emitter 85Kr have been estimated. These critical cells are hemopoietic stem cells, osteoprogenitor cells on bone surfaces and basal cells in bronchial epithelium. Cells in bone marrow and on bone surfaces are irradiated because of the solubility of noble gases in body tissue. The doses estimated here are much lower than the beta skin dose, but these cell doses are thought to be more pertinent in estimating health effects. The annual absorbed beta dose rates for the current global level of 85Kr of 15 pCi/m3 are 1 × 10−3 mrad for cells on bone surfaces, 2 × 10−5 mrad for hemopoietic stem cells and 3 × 10−4 mrad for basal cells in bronchial epithelium. For comparison, the annual alpha dose rates from the average concentration of 100 pCi/m3 of the naturally occurring noble gas 222Rn and its daughter products are 2.5 × 10−2, 3.6 × 10−2 and 27 mrad, respectively, to the same three cell types.
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