Abstract
Fine aerosol particles with aerodynamic diameter equal or <2.5 mu m (PM2.5) have been collected from industrial and residential areas of Greater Cairo, Egypt during two different seasons namely; autumn 2014 and winter 2014/2015. Energy dispersive X-ray fluorescence (EDXRF) analysis utilizing polarization geometry and three different secondary targets (CaF2, Ge, and Mo) was employed for the quantitative analysis of eighteen (18) elements in PM2.5 samples. Light elements like Na and Mg was possible to be quantified, whereas detection limits in the range of few ng m(-3) were attained for the most of the detected elements. Although, the average mass concentrations of the PM2.5 collected from the residential area (27 +/- 7 mu g m(-3)) is close to the annual mean limit value, a significant number of the collected samples (33%) presented higher average mass concentrations. For the industrial location, the average mass concentration is equal to 55 +/- 19 mu g m(-3), exceeded twofold the annual mean limit value of the European Commission. Remarkably high elemental concentrations were determined for the most of the detected elements from the industrial area samples, clearly indicating the significant influence of anthropogenic activities. The present optimized EDXRF analysis offered significantly improved analytical range and limits of detection with respect to previous similar studies, thus enhancing our knowledge and understanding on the contribution of different pollution sources. (C) 2018 Elsevier B.V. All rights reserved.