PIXE analysis of atmospheric aerosols from three sites in Mexico City

Abstract Samples of atmospheric aerosols were collected in three sites in the metropolitan area of Mexico City and analyzed with particle induced X-ray emission (PIXE). Stacked filter units (SFU) of the Davis design were employed to obtain samples of PM 15 (particles with dimensions smaller than 15 μm mean aerodynamic diameter) on polycarbonate filters. The study was conducted during the Summer of 2001, exposing the filters every two days for 24 h, starting at 8:00 h. Analysis of variance of the measured elemental concentrations showed differences in the mean concentrations for several elements at the sampling sites. Cluster analysis was applied to identify contributing sources, while known source profiles were used to relate soil components to define their sources.