Industrial activities and high traffic density are the most important heavy metal pollution sources in the urban area. Roadside dust created by atmospheric deposition can be one of the best indicators for heavy metal contamination levels. The present study reports the spatial distribution patterns and degree of heavy metal pollution (Cd, Cr, Ni, Pb, Zn and As) in 50 urban road dust samples from urban area of Sanandaj city. For this purpose, sampling points were selected from different roads including primary roads, high roads and main roads. The geographic coordinates of sampling points were recorded by Geographical Position System (GPS).Geo-accumulation Index (Igeo) and Integrated Pollution Index (IPI) were used to present the heavy metal contamination levels. The obtained results by geo-accumulation index suggest that the roadside dust was moderately contaminated with Ni and Cr, moderately to heavily contaminated with Pb and Cd, and heavily to extremely contaminated with As and Zn. The assessment of the data shows that 92% of all road dust samples had moderate pollution levels with IPI more than 2, indicating that the roadside dust quality of Sanandaj city has moderately been polluted by anthropogenic emissions. In order to compare the heavy metal concentrations in different parts of Sanandaj area, each heavy metal contamination was interpolated in Geographical Information System (GIS). Heavy metal distribution maps showed the different hot-spot areas of each pollution that indicated the high traffic density and industrial centers as the important factors affecting their concentrations in Sanandaj area.
