Two stage streaker and PIXE analysis for urban aerosol studies

A two-stage streaker sampler was exposed to collect size-fractionated aerosol samples in Geneva (Italy) in the spring of 1995. Samples were analysed by Particle Induced X-ray Emission (PME) at the Van Der Graaff facility of the INFN of Firenze. Hourly concentrations of elements from Na to Pb were measured both in the fine (<2.5 mu m) and coarse (2.5-10 mu m) fraction. Data were analysed by applying the Time Series and Principal Component (PCA) Analysis and the Source Profiles by Unique Ratios (SPUR) technique. Even with a short sampling possible it was possible, exploiting the hourly time resolution and the particulate size discrimination of the sampler, to deduce a picture of the aerosol composition in one of the most polluted districts of Genova. In particular, five major aerosol sources were singled out: their profiles were obtained using a minimisation procedure.