The emission level and pollution characteristics of platinum in dust,soils,and tree barks collected from Seoul,the capital of Korea,was published for the first time in Korea(Lee et al.,2006,2012).The total area of Seoul is about 605 km2 and its population was about 10.45 million and the number of registered motor vehicles was more than 3 million in 2011.Road dust samples were collected from 31 sites of various traffic volumes in Seoul,and from 4 control suburb sites in satellite cities for comparison.Geology in Seoul area is mostly composed with acidic rocks such as Jurassic granite and Precambrian gneiss and schist.The previous study confirmed that the important source of Pt in roadside environment is automobile catalytic converter,and that it indicates a tendency to increase Pt levels in road dusts along with traffic volume.The study also suggested that not only traffic volume but also driving style have a great influence on Pt levels in road dusts,for example 176 ng/g Pt in dust at the toll gate.In this study previous dust samples and newly collected 8 dusts within Seoul were reanalyzed to determine PGEs(Pt,Pd,and Ir)and traffic-related heavy metals by ICP-MS and ICP-OES.The concentration levels of Pt,Pd and Ir in reanalyzed 35 dusts were in the range of 0 – 444(76)ng/g,172 – 1,215(609)ng/g,0.8 – 7.4(2.9)ng/g,respectively.The level of Pt,Pd,and Ir in new 8 dusts ranged 25.6-98.5(65.6)ng/g,30.6 – 147.9(101.7)ng/g and 2.1-5.5(3.2)ng/g,respectively.The background of control site was 3.3 Pt ng/g,220 Pd ng/g,and 1.6 Ir ng/g.Palladium also shows similar distribution trend with Pt,and remarkably high concentration of Pd and Pt in dust was found in the heavy traffic areas,whereas Ir shows no correlation with Pt and Pd.The traffic-related elements such as Cr,Cu,Mo,Ni,Pb,Sb,and Zn were enriched in road dusts with high Pt level as compared with samples from control suburb areas.Closely correlated elements with Pt and Pd in dust were Be,Cr,Cu,Fe,Mo,Ni,Au,Hg,and Bi.