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Radiocarbon is one of the most widespread radionuclides in nature. Although it is probably best known for dating in archaeology, in the case of the general public, it represents a useful tracer to study our environment, both in the past and nowadays. For instance, carbonaceous particles, which are in many cases the most abundant among aerosols constituents, are believed to play a major role in both health and climatic effects of aerosols. In particular, measurement of radiocarbon concentration in particulate matter samples can give information on the contributions of the fossil fuels combustion and of natural sources to the carbonaceous fraction in aerosols. These measurements are especially effective when separately performed on different carbonaceous fractions, like elemental and organic carbon (EC and OC, respectively). Past climate is also studied thanks to old archives, as e.g. marine sediments can be. In this case, instead of radiocarbon dating the bulk sediment, a reliable method to fix chronological markers is represented by dating foraminifera tests of CaCO3 picked from different layers in the sediment. Both the aforementioned applications are characterized by the fact that the samples that can be collected for 14C measurements are typically very small, i.e. few mg or less (before any treatment). Accelerator Mass Spectrometry (AMS) is thus the only technique that can be applied to measure radiocarbon in such samples. Anyway, measurements cannot be so straightforward. In the case of the measurement of radiocarbon concentration in aerosol samples, a preparation line especially dedicated to the extraction of only the carbonaceous fraction of interest is mandatory. Actually, this line should include a combustion oven, from which either total carbon or EC and OC can separately evolve, and a system of traps to purify and collect the CO2. In the case of foraminifera tests (inorganic carbon), special care must be taken in the pre-treatment phase: foraminifera can be contaminated by heterogeneous materials, including organic matter too. Pre-treatment should thus remove all the possible contaminations without losing too much mass of the samples. Here we present an overview of the environmental radiocarbon applications the INFN-LABEC laboratory in Florence is involved in. 14C is measured by AMS, using the dedicated beam line installed at the 3MV Tandem accelerator. In particular, details about the hardware and the experimental procedures are given. [ABSTRACT FROM AUTHOR]

Fine particulate has become one of the biggest concerns in Italian cities pollution; the study of its composition is a powerful tool to evaluate the effects on health and identify pollution sources. PIXE is an established technique for particulate analysis (being multi-elemental, sensitive, fast, non-destructive and requiring no sample preparations) and has been extensively used, in combination with other IBA techniques, for particulate characterization in Italian urban environments. Here we report the preliminary results on the analysis of the aerosol collected, by two-stage continuous streaker samplers, in two Italian cities, Florence and Milan, during July 2001. Elemental concentrations have been extracted in the fine and coarse fractions, with hourly resolution, by PIXE-PIGE analysis, performed at the 3 MeV external proton beam INFN facility at the University of Florence. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]