Elemental characterization of PM10 and PM2.5 by SR-XRF in Córdoba City, Argentina

MARIA L. LÓPEZ; SERGIO CEPPI; GUSTAVO G. PALANCAR; GERMAN TIRAO; BEATRIZ M. TOSELLI

Campinas

Workshop; 21 Reunion Anual de Usuarios del LNLS; 2011

LNLS

Elemental characterization of PM10 and PM2.5 by SR-XRF in Córdoba City, Argentina   María L. López, Sergio Ceppi, Gustavo G. Palancar, Germán Tirao and Beatriz M. Toselli Departamento de Físico Química / INFIQC / CLCM /Facultad de Ciencias Químicas Facultad de Matemática, Astronomía y Física Universidad Nacional de Córdoba Ciudad Universitaria, 5000 Córdoba. ARGENTINA   Abstract         24-h samplings of PM10 and PM2.5 particulate matter have been carried out during the period July 2009–April 2010 at two places  of Córdoba, City, which are representative of different land use and human activities (Site 1: urban and Site 2: semi-urban). Measurements of total mass of PM2.5 and PM10 for the period show a positive and linear correlation between both fractions. Average ratio (PM2.5/PM10) for sites explored in this study was 0.62 approximately. The highest value in mass concentration for both fractions was found at the urban site. However, no significant temporal pattern or seasonal difference could be detected.  Synchrotron radiation X-ray fluorescence (SR-XRF) was used to determine the chemical compositions of aerosol particles. The elemental composition was different in the two fractions: in the finer one the presence of elements with crustal origin is reduced while the anthropogenic elements, with a relevant environmental and health impact, appear to be increased. An important but unmeasured component is likely constituted by organic and elemental carbon compounds. In more detail, the highest contributions to the coarse fraction for both sites were from Al, Si, K Ca, Ti, Fe, Ba, Mn and Pb.  Ni and Zn were found mostly in the fine fraction of the semi-urban site and S, V, Cr and Cu were found equally concentrated in both fractions.   However, the urban site presented equally important contributions from S, V, Cr, Co, Ni, Cu and Zn.  Multivariate analysis (Positive Matrix Factorization) of the SR-XRF data resolved a number of components (factors), which, on the basis of their chemical compositions were assigned physical meanings. Factor analysis was conducted with the two sizes aerosol composition data in order to identify anthropogenic and natural sources of the airborne particles. Preliminary results show that the coarse particles were mainly influenced by soil, resuspended dust, and metallurgical emission and fine particles were significantly attributed to several anthropogenic sources, such as motor vehicles, oil combustion, nonferrous metal source, and biomass burning.