Applied Nuclear Physics For Atmospheric Aerosol Studies

Abstract

Ion Beam Analysis (IBA) techniques are a powerful tool to study atmospheric aerosol composition, since they are quantitative, multi‐elemental, fast, high‐sensitivity and non‐destructive analytical methods. At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN in Florence an external beam facility is fully dedicated to measurements of elemental composition of atmospheric aerosols. All the elements with Z>10 are simultaneously detectable by Particle Induced X‐ray Emission (PIXE) in few minutes of beam time, including several important tracers of peculiar aerosol sources and potentially harmful elements, with minimum detection limits ranging between 1 and 10 ng/m3. Light elements (H, C, N, O), which are the main aerosol constituents, can be detected by means of in‐vacuum Particle Elastic Scattering Analysis (PESA). The application of both PIXE and PESA allows a complete mass reconstruction of aerosol samples. Since these methods are non‐destructive, it is possible to apply complementary techniques, like Ion Chromatography, on the same samples, obtaining information, for example, on the chemical composition. Scanning possibility may also be very useful, allowing time trend reconstruction by the analysis of time‐sequence aerosol deposits collected by continuous samplers. Using a two‐stage “streaker” sampler the concentration time series of all the elements with Z>10 can be measured with hourly resolution. In this paper the peculiarity of these methods will be highlighted and the results of recent campaigns will be shown, including the application of IBA techniques to aerosol daily and hourly samples, collected in urban and industrial areas.