Particle-size distribution of polycyclic aromatic hydrocarbons in urban road dust of Masan, Korea.

Concentrations and compositions of polycyclic aromatic hydrocarbons (PAHs) in particle size fractions of road dust sampled from contrasting areas of an industrialised city in Korea are reported. The largest amounts of road dust were present in industrial areas, followed by areas subject to heavy traffic, and the lowest amounts were associated with a residential area. The highest concentrations of PAHs were recorded in road dust sampled from the areas with the heaviest traffic (0.45-4.1 μg/g), followed by industrial areas (0.1-3.56 μg/g), with the lowest concentrations associated with a residential area (0.32-1.95 μg/g). PAH concentrations in the fractionated dust from the industrialised areas exhibited an inverse correlation with particle size. Although a similar general pattern was observed in the areas of heavy traffic, some increased concentrations associated with larger particles possibly reflect petrogenic contributions. Particles in road dusts from the residential area were generally smaller than those from the other areas, with PAH composition dominated by pyrogenic sources. PAH compositional profiles, evaluated through diagnostic isomeric ratios, indicate that exhaust emissions, rather than crankcase oils or tire and asphalt abrasion, are the major polluting source.