The study deals with the analysis of results on CO, NO, and SO2 emission recorded when burning pellets of oil cake, rape straw,
and birch sawdust in the low-temperature water boiler of the top combustion. The air was supplied to the boiler through a fan
under the grate at a speed of 1 m·s-1 and 2.5 m·s-1. There were significantly different emissions of CO, NO and SO2 under
varying conditions of airflow supply to the boiler. Emissions of NO and SO2 depended mainly on nitrogen and sulfur contents in
the biomass, while CO emissions were mainly dependent on the amount of supplied air. Such heating devices allow for
ecological combustion of pellets made of a plant biomass, but air distribution needs to be improved. It is advisable to develop
nomograms to facilitate the selection of airflow speed in relation to the biofuel used for a specific boiler type, ensuring its use in
accordance with the concept of sustainable development.