The results of measurements of the soot aerosol concentration with the help of the mobile vehiciles-laboratory in the framework of the seven TROICA (Trans-Siberian Observations into the Chemistry of the Atmosphere) many-year expedition along the Trans-Siberian railway and expeditions along the rout Moscow-Murmansk-Kislovodsk-Murmansk in spring and summer period are presented. The level of soot pollution in urban air of Russian cities is comparable with that in industrially developed countries of West Europe and USA, but substantially lower than in Beijing. The lowest values of the soot concentration in rural air were observed in summer of 1999 (0.1-1.0 μg/m3), and the highest, caused by the smokes of peatbog fires in the European part of Russia and grass burning along the Asian part of the railway line, in autumn of 2005 (0.6-5.6 μg/m3). Measurements at the circular railroad around Moscow were also carried out. A plume of the soot polluted air from Moscow was recorded on April 7 and 8, 2000.