Abstract
Interest is in vehicular trace elemental contributions to the environment, evaluated via analysis of road dirt. Results from SEM/EDX, ICP-MS and ICP-OES are compared for a wide range of elements. ICP-OES and ICPMS provide absolute quantification while SEM/EDX has provided weight % assessments. Roadside dirt has been sampled along busy campus roads of universities/research centres in Guildford, Riyadh, Kuwait City, Doha and Kuala Lumpur, satisfying interest in climatic influences as well as vehicle engine size (Gulf non-commercial vehicle engine capacities tending to be greater than those in the UK or Malaysia). A total of 100 street dust samples have been analyzed, elemental concentrations being reported for Mg, Al, Ti, Mn, Fe, Co, Zr, Mo, Ba, Tl, V, Rd, Pb, Cu, Zn, Ni, Cr, Cd, As, Hg and Au. For all five urban centres, Al, Fe, Mg, and Si values were found to be well above background while concentrations of Ti, Cr and Ba were lower than values reported by others. Au and Ag from catalytic convertors were found in some centres, albeit at very low concentrations and with particle sizes of the order of 0.5 µm. The various techniques offer complementary information on vehicular emission elemental concentrations in urban environments.
•Metal element concentrations investigated in road dirt.•Concentration obtained in urban road dirt in tropical, arid and maritime climates.•Elevated levels Al, Fe, Mg and Si found, less so in tropical and maritime roads than in the arid zones.•The concentrations of Mg show greater elevations in a few of the Doha locations.