1987 Volume 22 Issue 1 Pages 15-20
The acceptable level of radiation risk for public members, that is 10-5/y, was proposed by ICRP and other international organizations.
We studied to survey basic procedures of deriving this value and to derive an acceptable risk value in Japan by using similar procedures. The basic procedures to derive 10-5/y were found as follows; (1) 0.1 percent of annual mortality from all diseases, (2) 0.1 percent of life time risk, (3) one percent of mortality from all causes in each age cohort and (4) corresponding value to 1 mSv annual radiation exposure.
From these bases we derived the value of 10-5/y as acceptable risk level in Japan.
The perception to risk level of 10-5/y in conventional life was investigated by means of questionnaires for 1, 095 college students living in Tokyo. The risks considered in this study were natural background radiation, coffee, skiing, X-ray diagnosis, spontaneous cancer, passive smoking and air pollution. The most acceptable risk was the risk related with natural background radiation. And the risk of natural background radiation was more easily accepted by the students who had knowledges on natural background radiation. On the other hand, the risk from air pollution or passive smoking was the most adverse one.