Although atmospheric aerosol concentrations exhibit decreasing trend in last decades, the contribution of aerosol emitted by biomass combustion is opposite due to increasing wood combustion used for residential heating. Previous works determined that the share of aerosol of biomass burning origin was up to 50 % in winter. In this work, the data from aerosol mass spectrometer (AMS) and Positive Matrix Factorization (PMF) are used to elucidate biomass combustion aerosol impact at National Atmospheric Observatory Košetice (NAOK) and the results are compared with simple aethalometer model approach.