Environmental pollution and air quality are increasingly important topics within the areas of Smart City and state regulations. The aim of the article is to present the progress in the design of the emission monitoring system intended for use in non-industry heating appliances in households. The article analyses potential opportunities in aims of improving the design of a monitoring system that was experimentally tested on small heat source. Geometry modifications, sensor placements and orientation were evaluated using Computational Fluid Dynamics in Ansys Fluent software 2022 R2 including both air and CO/CO2 dispersion models. The final geometry introduced a streamlined funnel along with a separation element, which distributed the air flow evenly between the sensors. The results showed more uniform air flow as the standard deviation of downstream velocity improved from ± 0,693 m/s to ± 0,297 m/s. In conclusion, these outcomes assist in the reduction of air pollution.