The study was undertaken to determine the bacterial mutagenicity (Ames test) and chemical characteristics of respirable particulate matter collected in the area. Fine particle concentrations for the sampling period of November 16th to January 7th ranged from 1.19 to 209.8 microgram/cu m. Bioassay samples from ambient air fine particle concentration periods of 25.6 to 209.8 microgram/cu m showed indirect acting mutagenicities of 6.64 to 77.8 rev./cu m with a mutagenicity/particle concentration correlation coefficient of 0.89. The indirect acting mutagenic potency values ranged from 0.29 to 1.44 rev./microgram of extracted organics and averaged 0.73 +/- 0.26. Correlations between fine particle concentration, indirect acting mutagenicity and PAH concentrations were observed for most periods throughout the study. A comparison of ambient air samples collected from wood smoke impacted residential areas in Raleigh, NC, Albuquerque, NM and Juneau showed that the relationship between ambient air mutagenicity and fine particle concentration was similar for each location.