Five mutagenic and/or carcinogenic polynuclear aromatic hydrocarbons (PAHs), and Salmonella mutagenicity in airborne particles collected at three stations (industrial, commercial/residential, and agricultural areas) in Santiago, Chile were measured, and compared with the same measurements in the Tokyo metropolitan area. PAH concentrations showed daily variations in both cities. The concentrations of fourring PAHs were higher in the Tokyo area than in Santiago, and the concentrations of five-or-more-ring PAHs were higher in Santiago than in the Tokyo area. Mutagenic activities also showed daily variations in both places, and were generally higher in Santiago. In the Tokyo area, the mutagenic activities were higher under conditions of TA98-S9 mix than under TA98+S9 mix while in Santiago, the activities were similar under the two mixes. There were good correlations between PAH concentrations and mutagenic activities in both areas. In Santiago, mutagenic activities and PAH concentrations were higher in the commercial/residential area and the industrial area than in the agricultural area.