The combustion processes of biomass occurring in furnaces run with an emission of exhaust gas consisting of groups of chemicals which occur both in gaseous and particulate-bound form. The purpose of the work presented in this paper was to investigate the impact of wood combustion processes occurring in domestic heating units (DHUs) on the emission of particulate matter (PM) and other exhaust components. The process of combustion was divided into three steps: A. firing, B. combustion, and C. post-combustion. During fuel burning, the weighting platform was used to measure variations in the mass of fuel and a gaseous analyzer was used to measure gaseous exhaust components such as CO2, CO, O-2 and SO2. A dust sampler equipped with a dilution tunnel, a filter holder and a pump were installed in the stack. The samples of PM were collected on quartz fiber filters with a diameter of 47 mm. The PM was then analyzed for the presence of inorganic and organic components. The results obtained in the studies confirmed the influence of using the accumulation layer on the emitted exhausts. Application of accumulation layer led to decrease the emission of gaseous fumes (NO, NOx and SO2), although, the CO and PM emission were higher. One also observed the impact of combustion phase on the chemical composition of collected PM. The highest measured concentrations of analyzed PAH compounds were determined for acenaphthene (Ace) and benzo(a)pyrene (BaP). In all analyzed events BaP mostly contributed to the budget of PAHs in the final phase of burning: during the post-combustion process, when the temperature in the combustion chamber decreased. The application of the accumulation layer enabled to decrease the BaP concentration in the ignition phase of burning. The highest concentration of Ace was observed for the combustion phase using the Stove 1, while in the Stove 2, both with and without an accumulation layer, the Ace concentration was higher in the initial phase of burning.