An analysis on polycylic aromatic hydrocarbons (PAHs) deposited in road dust at downtown areas in a city of Korea

An analysis on polycyclic aromatic hydrocarbons (PAHs) deposited in road dust at downtown areas in a large city of Korea, Ulsan, was carried out in March 2006 to identify the concentrations as well as characteristics of these compounds. Road dust samples were taken at 3 sites in which 2 sites are in downtown areas and 1 site is in a typical residential area of Ulsan. Road dust samples were separated into 4 particle size categories as follow: 850 mum - 2000 mum, 180 mum - 850 mum, 75 mum -180 mum, and less than 75 mum. After being extracted by a mixture of dichloromethane and n-hexane (1:1), the extract was filtered and concentrated to 2 ml by using nitrogen evaporator. 16 PAHs included in USEPA list were analyzed by high performance liquid chromatography (HPLC) method. At downtown areas, individual PAHs concentrations in road dust ranged from 0.06 ng.g^-1 to 146.43 ng.g^-1; the total PAHs concentrations ranged from 39.23 ng.g^-1 to 309.70 ng.g^-1, depended on particle size of road dust samples. Based on size fractions of road dust in each area, PAHs contents in a weight unit of road dust were estimated. PAHs contents in road dust at 2 downtown areas were 52.46 ng.g^-1 and 245.12 ng.g^-1, respectively. The concentrations of PAHs in road dust in 2 downtown areas were quite different because of the differences in vehicle density and speed. When compared with road dust in a typical residential area, the concentrations 0/ PAHs in road dust at downtown areas were much higher, from 2.7 times to 12.4 times.