干旱区生态环境知识资源中心

Resuspended desert dust is an important air pollutant in both local and transboundary levels. Research on the resuspension and properties of desert road dust particulate matter (PM) was performed with dust samples from the provinces of Kandahar, Herat and Ghor in Afghanistan, and the province of Baghdad in Iraq. Measurements of the concentrations of airborne PM in Kandahar province showed that near the military unit PMtotal ranged from 58.3 mu g/m(3) to 85.5 mu g/m(3), while in the motorcade the concentrations ranged from 13787.9 mu g/m(3) to 18181.8 mu g/m(3). The particle size distribution (PSD) of the resuspended dust samples in laboratory conditions revealed that the PSD may have a bi-modal shape with a clearly defined mode (d = 1.98-2.13 mu m), and less expressed second mode at similar to 1 mu m. The highest amounts of resuspended PM resulted from the samples taken at Kandahar province. The dust from other regions showed lower amounts of resuspended particles (similar to 75% lower in Ghor, similar to 85% in Herat, and similar to 96% in Bagdad). The X-ray diffraction (XRD) analysis of dust showed the presence of calcite, quartzite, albite, muscovite, potassium-feldspar, and nimite in the samples. SO42- concentrations in the road dust samples ranged from 71.3 +/- 8.5 x 10(3) mu g/kg to 221.1 +/- 18.3 x 10(3) mu g/kg, and the amounts of Cl-varied from 378.2 +/- 81.9 x 10(3) mu g/kg to 3876.2 +/- 295.2 x 10(3) mu g/kg. The results of particle size distribution and composition were discussed with respect to their potential negative influences on road vehicles.