Two typical profiles of nanoparticles were observed over the southern part of Western Siberia. The first type represents the well-known distribution that can be well described by the empirical equation proposed by Jaenicke. The second type of vertical profiles exhibits the so-called z-shaped structure with the secondary maximum in the free troposphere. Analysis of the data obtained in this study enabled us to estimate a new particle production rate in the free troposphere. The maximum production rate was in the 10-3-10-2 см-3 x с-1 range.