The combustion of biomass is accompanied by the formation of particulate matter, the presence of which in the atmosphere harms human health. It is important to show the issues of reducing these pollutants and their impact on human health. This article focuses on the process of biomass combustion. The used model consists of two parts: the combustion chamber and the flue gas tract. The article shows four types of modification of the flue gas tract designed to reduce the amount of particulate matter in the atmosphere. Baffles are located in the flue gas tract, which is designed to capture the particulate matter. The final model is simulated by turbulent–viscosity models, k-ε realizable model, and then k-ω shear stress transport model. The interaction between turbulence and chemical reactions is expressed by using the Eddy Dissipation Concept model. The results then show different profiles of temperature, velocity, and particle distribution. Based on the evaluated data from two different calculations, it can be concluded that the baffles have a significant effect on the reduction of particulate matter in the atmosphere. The used baffles are able to capture mainly particles with a diameter greater than 100 µm. A significant number of particles with a diameter lower than 100 µm flows from the flue gas tract to the surrounding environment.