*Article* **Modeling Pollutant Emissions: Influence of Two Heat and Power Plants on Urban Air Quality**

**Robert Cichowicz \* and Maciej Dobrza ´nski**

Faculty of Architecture, Civil and Environmental Engineering, Lodz University of Technology, Al. Politechniki 6, 90-924 Lodz, Poland; maciej.dobrzanski@p.lodz.pl

**\*** Correspondence: robert.cichowicz@p.lodz.pl

**Abstract:** Large industrial plants, power plants, and combined heat and power plants are popularly believed to be the main sources of point emissions, affecting both local and global air quality. This is because these installations emit significant amounts of pollutants at high altitudes every year. In this study, we investigate the impact of two solid fuel (hard coal)-fired CHP plants located within the urban agglomeration on the air quality of the city of Lodz in Poland (Europe). We used an OPA03 computer software to model the spatial distribution of pollutants. The results show that the annual average concentrations of pollutants were highest at an altitude of 25 m above ground level and decreased at lower measurement heights. The concentrations did not exceed permissible levels, reaching only 4% of national and international regulatory limits. We also made field measurements during the winter heating period, using an unmanned aerial vehicle (UAV) equipped with sensors to map the distributions of dust and gas pollutants in the areas with the highest concentrations of emissions from the two heat and power plants. Overall, the field measurements confirmed that it is not high-altitude emissions that have the greatest impact on local air quality.

**Keywords:** air quality monitoring; SO2; NO2; NOX; PM10; PM2.5; outdoor air quality; air flow aerodynamics; air quality modeling
