This paper concerns the use of neutron activation analysis as a means of analyzing airborne particulate materials. Sample collection and handling, use of standards, irradiation procedures, and counting periods are discussed. In addition, the radionuclides and gamma-ray energies are given for several elements. Analysis of different size fractions of particulate air pollution from the Columbia, Missouri area indicates that elemental fractionation patterns are more complex than the particle mass fractionation itself. Detailed discussion of the data is not presented because results are preliminary.