Determination of elemental composition of air particulates and soils in Khartoum area

Abstract

Investigations were carried out for elemental composition of air particulates in the background air and near roadsides in Khartoum area. Investigations were also performed for the elemental composition of soils at the same locations. A cyclone and a dichotomous virtual impactor were
used to measure the air particulates. The cyclone was adjusted to collect particles having an aerodynamic diameter of 2.5!m. The virtual impactor, through its fine channel, was capable of collecting airborne particles with an aerodynamic diameter of 2.5 μm. Energy Dispersive X-Ray Fluorescence (EDXRF) analysis was used to study the elemental concentrations of the air and soil samples. The analysis of the results indicated that all elements in the proximity of roadsides have elevated concentrations compared to the background air levels. Enrichment factors were calculated relative to crust rock and Khartoum soil. The results showed that the elements K, Ca, Ti, Fe, and Sr in the aerosols have their origin from the soil, while the elements Zn, Ni and Pb have their source from automobile emissions. The results also indicated a correlation between lead and bromine. The lead to bromine ratio was found to be within the range of those derived from vehicular exhaust, and in good agreement with the ratios obtained from some other countries.