Elemental composition of urban aerosol collected in Florence, Italy

An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. The aim is to determine the a erosol elemental concentrations as well to identify pollution sources. For our investigation, we use the external PIXE-PIGE beam facility of the Van d e Graaff accelerator of INFN at the Physics Department of the Florence Univ ersity. We report here an overview of the results of the PIXE analysis of a long te mporal series (about 1 yr) of PM10 particulate collected on Millipore filte rs on a daily basis in three different sites (characterised by different ur ban settings). Daily concentrations of more than 20 elements have been obta ined. From the observed elemental concentrations seasonal variation were fo und. A relevant decrease of S, Pb and Pr levels has been found with respect to 10 yr ago. Four main sources (traffic, sulphates, soil-dust and wind-tr ansported sea-salt) have been extracted with the help of factor analysis. ( C) 2000 Elsevier Science B.V. All rights reserved.