Elemental composition of PM_(2.5) particles sampled in industrial and residential areas of Taif, Saudi Arabia, using energy dispersive x-ray fluorescence

摘要

The present work is the first part of an initiative to evaluate the trace element composition of atmospheric aerosols PM_(2.5) in two different areas of Taif city, Saudi Arabia. The influence of different inorganic matter on regional air quality has been demonstrated. Atmospheric aerosols of PM2 from two different sites (industrial and residential) of Taif were collected and analyzed during June and July 2011. The industrial site was situated at the famous industrial areas in Taif whereas the residential site was situated at the most crowded street in Taif, namely Television Street. Atmospheric aerosols have been collected on polycarbonate filters loaded inside a collection cartridge in a cyclone of PM_(2.5). The duration of the collection was 24 hours at air flow of 3 L min~(-1). Energy Dispersive X-ray Fluorescence (EDXRF) with Mo secondary target has been chosen for direct solid sampling analysis because of the relative simplicity and the availability of the technique in many routine laboratories. The use of Mo secondary target has a lot of advantages for decreasing the continuum radiation coming form the x-ray tube. Quantitative X-ray Analysis Software (QXAS/AXIL) has been used for the quantitative analysis of the atmospheric aerosols PM_(2.5). A certified reference material (#2783, Air Particulate on filter media, NIST, USA) has been used in order to verify the validity of the obtained results. Direct solid sampling analyses were carried out for fifteen elements using EDXRF namely; S, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Pb, and C. The measured concentrations of the potentially hazardous trace elements As, Cu, Sb, Cr, Mn, Ni and Pb were below the limits defined by international guidelines and national standards of ambient air quality. Further long-term research is required to validate the quantification of trace elements collected on polycarbonate filters.