Resumen:
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.