抄録
Radon daughters generated from the earth has the high risk which lung cancer induces, and is considered to be one of the serious indoor contaminants in Europe and America. National Institute of Radiological Sciences started the simultaneous measurement project of the amount of generating to it for 20 cities in East Asia where data are not ready enough until now. In this report, the amount of generating of radon in Sapporo was identified. And the amount of required ventilation in urban space was presumed using the identified amount of generating. Moreover, risk assessment of natural radioactive substances was investigated.
