Characterization of the aeolian aerosol from Cape Verde by k_0-INAA and PIXE

摘要

Due to its location on West Coast of Africa, Cape Verde is highly influenced by Sahara Desert dust events being an optimum place to observe and study the African aeolian aerosol. During 2011, particulate matter with an aerodynamic diameter lower than 10 μm (PM_(10)) was sampled in Santiago Island and its chemical composition was evaluated by k_0-instrumental neutron activation analysis (k_0-INAA) and particle induced X-ray emission (PIXE). This study showed the existence of a seasonal intrusion of dust from Africa (that occurred from October to March) characterized by significant increases of PM_(10), mineral elements and anthropogenic particles concentrations. In 2011, the PM_(10) health-based air quality guidelines defined by WHO, EU and USEPA were exceeded. Cape Verde PM_(10) composition was characterized essentially by high concentrations of elements originating from the soil (Ca, Ce, Co, Fe, K, Mg, Mn, Rb, S, Sc, Si, Sm, and Ti) and sea (Br, Cl, and Na); and low concentrations of anthropogenic elements (As, Cr, Cu, Ni, Pb, Sb, V, and Zn). k_0-INAA and PIXE were fundamental tools for the determination of airborne chemical elements in Cape Verde. Their multi-elemental capabilities in association with low detection limits made it possible to determine the majority of the element concentrations of environmental interest.