The complementarity of PIXE and PIGE techniques: A case study of size segregated airborne particulates collected from a Nigeria city

The Proton Induced X-ray Emission (PIXE) technique is a reliable ion beam analytical tool for the characterization of thin aerosol samples, but it can underestimate the lightest measurable elements (such as Na, Mg, Al and Si) owing to the absorption of their X-rays inside the sample. The Proton Induced Gamma-ray Emission (PIGE) technique could be employed as avalid means to determine corrections for such an effect. Hence, in this study, Fine (PM_2.5) and Coarse (PM_10–2.5) particulate matter samples collected at Ikeja, Lagos-Nigeria, using a double staged 'Gent' stacked sampler were analyzed for their elemental concentrations using an external beam set-up for simultaneous PIXE and PIGE measurements. The measured PIXE concentrations as well as the PIGE correction factors for Na and Al detected in the PM_10–2.5 samples (collected on polycarbonate Nuclepore membranes) are reported. The concentrations of 24 elements (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, Cs and Pb) detected in both fractions were displayed, discussed and likely sources of these elements were also identified. - Highlights: • Daily mass concentrations of PM_2.5 and PM_10–2.5 aerosols from a Nigerian city were established. • External Ion Beam Experiments of Proton Induced X-ray Emission (PIXE) and Proton Induced Gamma-ray Emission performed on Nigerian urban aerosol. • PIGE correction factors for Na and Al detected by PIXE in the PM_10–2.5 fraction were determined and correction factors established. • Twenty-four elements as well as their concentrations in and enrichment factors PM_2.5 and PM_10–2.5 aerosol fractions were revealed. • Emission sources contributing to PM_2.5 and PM_10–2.5 elemental pollutants was investigated and indentified