Fine atmospheric particulate material was collected at five sites in upstate New York and analyzed for its trace element composition by instrumental neutron activation analysis. Of the 3700 daily samples collected over a 2-yr period, 1459 were analyzed for 39 elements, providing a large and detailed data set. Factor analysis (FA) was used to identify potential pollution sources or source regions and to construct inorganic source profiles for each. Following FA, the method of absolute factor scores-multiple linear regression was used to estimate the absolute elemental contribution of each of the identified sources. Factor analysis identified nine sources impacting the sampling region. Seven of these were found to be present in varying degrees among of the sampling sites. The other two sources had more localized impacts and were observed at only one of the sites each. Regional sources (such as the midwestern United States and eastern Canada) and crustal/soil material accounted for the greatest amount of the trace elements measured in the collected material.