PIXE analysis of atmospheric aerosols from a simultaneous three site sampling during the autumn of 1993 in Mexico City

A simultaneous three site aerosol sampling was performed during the autumn of 1993 in Mexico City. Stacked filter units of the Davis design were used to collect atmospheric aerosol samples, providing two samples per unit and separating particles into ''coarse'' and ''fine'' according to size. The samples were taken simultaneously at three different sites from 6:00 to 12:00 h, on seven alternate days. Elemental concentrations of aerosol contents were determined by PIXE analysis performed both at the Florida State University and at the ININ facilities. 18 elements were found systematically in most of the samples, including S, Cl and heavy metals. Fine mass concentrations of sulfur were more abundant than coarse mass concentrations at all three sites. Enrichment factors and correlation matrices were computed to identify possible pollutant sources.