Wood combustion on a local scale may cause the emissions of more than 100 different toxic and carcinogenic substances. Therefore, it appears that biomass combustion paradoxically involves the risk of environmental contamination and poses a threat to human health. This occurs under unfavorable conditions or due to the use of combustion technology unsuitable for a given fuel. Fuel combustion in low power boilers is carried out with the use of fuels with highly diversified technical and elementary parameters, and the economic aspect is for households ever more frequently to be a determinant of the form and quality of the combusted fuel, regardless of the boilers within which the fuel undergoes thermal conversion. The aim of the research was to determine the concentration of contaminations emitted during the combustion of pellets made of Virginia mallow biomass in a 32 kW boiler with automatic fuel loading adapted for wood pellet combustion on a test bench. The concentrations of 16 polycyclic aromatic hydrocarbon PAHs and benzo(a)pyrene B(a)P was determined, the indicators of emitted contaminations were specified, and the concentration of VOC (methane, ethane, ethylene, propane, propylene, n-butane, and pentane) in flue gases was defined. The determined indicators of emission for 16 PAHs equaled: 2.9 mg·kg^-1, i.e. 170.0 mg·GJ^-1, and for B(a)P 0.03 mg·kg^-1, i.e. 1.8 mg·GJ^-1.