Seasonality of airborne trace element sources in Aracaju, Northeastern, Brazil

Abstract

In this work the urban area of Aracaju city, located in the State of Sergipe, Northeastern Brazil was the site for simultaneous collection of suspended particles (TSP) and inhalable particulate matter (PM10) aiming an evaluation of the air quality parameters. Concentrations of Cd, Co, Cu, Fe, Mn, Ni, Pb and V in TSP and PM10 were determined by inductively coupled plasma mass spectrometry (ICP-MS). Iron was the most abundant element found in both particulate samples. Through chemometric tools, it was possible to point out that the contributions to the TSP and PM10 formation are similar, and strong correlations were observed between Fe-Mn (0.83) and Cd-Pb (0.93) in TSP, and Fe-Mn (0.90), Fe-Cu (0.81) and Cd-Pb (0.97) in PM10, an evidence that these species are from sources related mainly to soil resuspension and vehicular traffic. Enrichment factor (EF) and geoaccumulation index (Igeo) showed an influence of fossil fuel burning in the composition of TSP and PM10. Through principal component analysis (PCA) and hierarchical cluster analysis (HCA) it was observed particle size distribution groupings according to its aerodynamic size. Evaluation of the concentrations obtained for the collected samples according to the seasons (dry and rainy), indicated the influence of both, biogenic (resuspension of soil and marine aerosols) and anthropic (vehicle traffic and biomass burning) sources.