Investigation of environmental radioactivity level around Taipei

The concentrations of 222Rn (radon) and its progeny with a surrounding environmental gamma-dose rate were measured simultaneously inside and outside of buildings at eight locations around Taipei in Taiwan. Concerning summer radon in Taipei, indoor concentrations were estimated to be about 20 Bqm-3 with about 90 nSvh-1 of environmental gamma, and outdoors, about 10 Bqm-3 with about 70 nSvh-1. The equilibrium factors were calculated to be 0.2-0.3 indoors and 0.3-0.4 outdoors. Indoor radon concentration had a week positive correlation with the gamma dose rate. Since there is a possibility that high radon concentrations exist indoors during the cool season in Taiwan because of extremely low ventilation rates in the dwellings, a winter survey in January through February will be needed for the future estimation of the annual effective dose. (author)