| Detection limits of the PIXE technique were improved approximately 50% for PIXE cascade impactor (PCI) samples, by reducing the analytical beam size from 0.20 cm2 to 0.09 cm2 as a result of the characterization of the PCI aerosol deposits. Assessment of errors associated with the PCI application demonstrated that total sample masses varied on average by 15%. Samples collected with poorly sealed PCIs were generally underloaded. The presence of wrinkles in the impaction material did not seem to have a significant impact on the results. Elemental concentrations, obtained in Thunder Bay and Rouyn-Noranda, were strongly dependent on environmental conditions such as precipitation and wind direction, respectively. Source apportionment of elements at both sites was achieved using distributions of concentrations on size-fractionated aerosols, concentration profiles, enrichment factors and correlation coefficients. Elements Al, Si, Fe, Ti, Ca, Mn, K, Cr, Sr and Ni are believed to be of crustal origin at both sites. Anthropogenic origin is suspected for elements Br, Se, As, Cu, S, and Zn at the Rouyn-Noranda location. |
