Airborne particles (n=541) , river waters (n=541) and surface soils (n=544) were collected from five geographically different regions of Japan (Hokkaido, Kanto, Chubu, Kinki and Kyushu regions) between 1996 and 2003. Extracts from those samples were measured and compared by a pre-incubation method using Salmonella typhimurium strains and a standard reference. Airborne particles were collected by high volume air samplers. All organic extracts of airborne particles except for some of those from Kinki region were mutagenic toward both TA98 and TA100 strains with and without S9 mix. Higher mutagenicity of airborne particulate extracts was observed for the samples collected at sites in heavy traffic areas and nearby industrial steel works. Mutagenic activity of airborne particles showed a gradual decrease over the period of the 7 years. Most of the blue rayon-absorbed materials from river waters exerted strong mutagenicity toward YG1024 strain with S9 mix, and the potencies varied widely among sampling sites. Blue rayonabsorbed materials showed no strong mutagenicity in TA100 or YG1029 strains, with or without S9 mix. Non-agricultural surface soils were collected from roadsides, parks and other open areas from each region. All organic extracts of surface soils were mutagenic toward either TA98 or TA100 strains with or without S9 mix. Mutagenic activities of surface soil extracts showed a wide range, and the effect of additional S9 mix on the activities depended on samples.