Elemental composition of PM0.25 collected in an urban site of Argentina: A first case study

A total of 175 aerosol samples were collected during the winter-spring months of 2014–2015 in Córdoba, Argentina. The samples were collected in five size fractions that ranged from <0.25 to 10 μm using a SIOUTAS impactor in a 6-h period and analyzed by synchrotron radiation X-ray fluorescence to obtain elemental aerosol mass concentrations for As, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, Si, S, Ti, V, and Zn. An analysis of the distribution of the elements in the different collected fractions was performed to infer the most likely sources of particulate matter. From the analysis, it was found that the particulate matter fraction smaller than 0.25 μm was mostly affected by emissions from traffic and combustion, while the particulate matter fraction ranging from 2.5 to 10 μm was mostly influenced by re-suspension of road dust. In addition, the results indicated the presence of Si, typically found in coarse particulate matter and in large amounts in particles smaller than 0.25 μm. To infer the sources of aerosols causing the deterioration of air quality, principal component analysis was performed. The smallest particles, due to their toxicity, are likely to produce more adverse health effects than larger size fractions. These results show the need to monitor their atmospheric emissions in order to preserve air quality. Synchrotron radiation X-ray fluorescence analysis of the elemental composition of particles smaller than 0.25 μm in Córdoba city constitutes the first contribution to the knowledge base of the concentrations of toxic metals in this size fraction. These results are relevant because there is a lack of data in South American cities.