Size distribution measurements of radon progeny aerosol particles were perf
ormed using a screen-type diffusion battery method for both indoor and outd
oor air in Japan. The results were as follows; a large part of the peak rad
ii were distributed between 0.1 and 0.2 mu m. The geometrical standard devi
ation was 2-3. (C) 2000 Elsevier Science Ltd. All rights reserved.