Response of vehicular lead to the presence of street dust in the atmospheric environment of major roads.

Size fractionated particulate samples were collected from the roadside atmosphere of three major roads within the Brisbane Metropolitan area, using a high volume sampler fitted with an Anderson impactor. Street dusts were also sampled at these sites. Deposition samples were collected simultaneously with those of atmospheric particulates from periods with and without rainfall. All types of samples were quantitatively analysed for lead and various anions and cations. The pH and electrical conductivity for street dusts and deposition samples together with total solids content of deposition samples were also determined. Results showed that at sites where the process of street dust resuspension was at a minimum, the bromide-to-lead ratios were comparable to the reported ratio in uncombusted petrol. However, the relatively higher bromide-to-lead ratios observed at sites with active street dust resuspension indicate the existence of a process by which fine lead particulates are removed from the atmosphere by resuspended coarse dust particles.