Size distribution and probable sources of trace elements in submicron atmospheric particulate material

Size-segregated atmospheric particulate material was collected at a rural location in the Great Smokey Mountain National Park, Tennessee, and at an urban site in Pasadena, California. The elemental composition of this material was determined by Instrumental Neutron Activation Analysis. Elements identified as being of anthropogenic origin had mass median diameters of below one micron, while elements of crustal origin were generally found to have a mass median diameters well over one micron. Some of the Pasadena samples however had elevated concentrations of the typical crustal elements Al, Fe, La, and Ce in the finer size fractions, probably due to motor vehicle emissions.