The incompletely combusted particles from power plants, local heating installations and traffic and plant remnants were studied in dusts and fluvial sediments in exposed areas of downtown Prague by optical and electron microscopy, and chemical analysis. Structural characterization of carbonaceous particles was done by GC/MS and Py-GC/MS. Total organic carbon (TOC) content of the studied samples ranges from 3.69 to 14.77 wt.% black carbon (BC) content from 0.13 to 2.61%. Modern organic matter such as wood tissues, plant remains and organs, pollen grains, and fungal spores with R(r) reflectance lower than 0.20% are common in most samples. Algae and bituminite are enriched in fluvial sediments. Insect fragments are typical for dust samples. Combustion residues, particularly soot in dust particles, dominate a broad range of high reflecting carbonaceous particles of anthropogenic origin. Charcoal prevails in wood ash and has been found in fluvial sediments with char particles. Molecular biomarkers varied with sample origin. Polycyclic aromatic hydrocarbons (PAHs) distribution exhibited no correlation with BC. (C) 2009 Elsevier B.V. All rights reserved.