This research was aimed at analysing ash and slag dumps as objects of negative impact on atmospheric air, as well as at studying available methods for dust suppression. The existing ash and slag dump of the Novo-Irkutskaya combined heat and power plant, located in the forest park area between the cities of Irkutsk and Shelekhov, was considered. The territory adjacent to the ash dump is represented by forests in its south-eastern, eastern, and south-western parts, while the north-eastern part – by farmland. The operation of the ash and slag dump of the Novo-Irkutskaya thermal power plant leads to an increased level of atmospheric air pollution in the nearby residential area, which is situated outside the sanitary protection zone. This indicates the need to develop and implement measures to reduce dust formation from the surface of the ash and slag dump. In order to identify the most effective dust reduction method, it is important to calculate changes in emissions depending on the method used. To this end, we approximated the effective area of the dusting surface and the current ash particle outflow, which allowed determination of the surface concentrations of pollutants outside the ash dump area. Using a calculation method, we proved that the minimum rate of ash particle removal is observed when the water level in the nearby clarification pond is increased. It should be noted that, in addition to environmental aspects, economic factors should also be taken into account when developing environmental measures