Intra-urban spatial variability of PM2.5-bound carbonaceous components

► Concentrations of PM2.5 associated carbonaceous species were measured from 4 urban sites in Denver. ► Spatial variability was assessed using the Pearson correlation coefficient (r) and coefficient of divergence (COD). ► Near-highway sites exhibited higher concentrations of EC, OC, PAHs, and steranes than residential sites. ► Large uncertainties associated with sampling and species quantification will bias the estimation of r and CODs. ► CODs derived from co-located samples are useful points of reference to analyze spatial variability of PM2.5 species.