Short-term changes in the contents of platinum group elements (PGEs) in road dust

The short-term variation of concentrations of platinum group elements, PGEs, in Shanghai road dust is analyzed and discussed. The dust samples were collected from Zhongshan North Road (from the East China Normal University to Wuyi Road), Changning Road (from Zhongshan West Road to Anxi Road) and Yangliuqing Road (from Jinshajiang Road to Wuning Road). The results showed that the concentrations of Rh, Pd and Pt in road dust ranged from 24.95~36.24 ng·g^-1 (29.42 ng·g^-1), 85.34~158.89 ng·g^-1 (117.88 ng·g^-1), and 20.15~48.48 ng·g^-1 (34.42 ng·g^-1) respectively. Compared with the reference point, the concentrations of Rh, Pd and Pt in road dust were increased 19.48, 12.17 and 64.94 times respectively. In comparison with international levels, the road dust concentrations of Pd and Rh in Shanghai were intermediate, but the concentration of Pt was low. In general, weather conditions were the main cause of short-term changes in PGE concentrations and load. Rainfall decreased the concentrations of PGEs, but different types of rainfall changed the load of PGEs differently. More rainfall resulted in lighter load, and vice versa. After continuous rainfall, the concentrations and the load of PGEs reached a minimum. The wind power increased the concentrations of PGEs, but changed the load of PGEs complicatedly. Under continuous dry and calm weather conditions, the concentrations and load of PGEs were maximized, and tend to mitigation.