CONICET | Buscador de Institutos y Recursos Humanos

Trace metals are ubiquitous in urban ambient air, with mass concentrations in the range of a few ¹g m-3 down to less than a few ng m-3. To measure such low concentrations represents a challenge for chemical and physical analysis. In this study, ambient aerosols were collected in Cordoba (Argentina) from April 2010-June 2012, in 3-h intervals and four size fractions, using a SIOUTAS impactor (SKC). In addition, 24 h samples in the PM2.5 fraction were collected with the DPS-SKC impactor. Aerosol samples were excited with a monochromatic excita-tion beam at two different energies both, with and without the presence of air to obtain size-segregated elemental aerosol mass concentrations for Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn under the selected experimental conditions. The high sensitivity of SR-XRF allowed for very low detection limits for most of the above elements. The data obtained with this technique aims to illustrate that there is a considerable gain of relevant information when time resolution for measurements is increased from 1 day to 3 h. The individual size fractions of a specific element seems to indicate different short-term patterns although further analysis need to be performed. The aims of this work were: (1) to present detailed source apportionment results for PM2.5 and the minor fractions (with time reso-lution) measured in the city, and (2) to compare with samples collected from July2009-April 2010 to verify possible seasonal and inter annual variability.Acknowledgements: This research was partially supported by the National SynchrotronLight Laboratory (LNLS), Brazil, by the Agencia Nacional de Promoción Científica yTecnológica (FONCyT), by the Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET), and SECyT (UNC). M. Achad thank FONCyT, and M.L. López and S.Ceppi thank CONICET for graduate fellowships.

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