Wind-Trajectory Method for Determining Compositions of Particles from Major Air Pollution Sources

Abstract

Compositions of particles from several types of air pollution sources can be determined by a wind-trajectory method applied to a large data set on particle compositions obtained in St. Louis by other workers, who operated ten dichotomous samplers for 2 years and analyzed all samples by X-ray fluorescence. Samples heavily influenced by emissions from specific sources are identified by searching the data for unusually large concentrations of each element. Mean wind directions during the identified sampling periods often cluster about angles pointing to dominant sources of the elements. Trajectories for a given element obtained at different stations often converge near the dominant source of the element. Compositions of the particles released are determined from linear regressions of concentrations of each element in the samples making up the trajectories versus those of prominent elements from the source. Compositions of particles released by an iron works, an iron-and-steel complex, a pigment plant, a municipal incinerator, lead and zinc smelters, two copper plants, a refinery, a fertilizer plant, and motor vehicles have been determined. The results obtained are more appropriate for receptor model use than those based on traditional stack measurements. Fugitive emissions are observed for several plants.