Emission factors (EFs) of gaseous pollutants, particulate matter, certain harmful trace elements, and polycyclic aromatic hydrocarbons (PAHs) from three thermal power plants (TPPs) and semi-industrial fluidized bed boiler (FBB) were compared. EFs of particulate matter, trace elements (except Cd and Pb), benzo[a]pyrene, and benzo[b]fluoranthene exceed the upper limits specified in the EMEP inventory guidebook for all combustion facilities. The comparison of trace elements and PAHs content in fly ashes (FAs) from lignite and coal waste combustion in TPPs and FBB, respectively, as well as the potential environmental impact of FAs disposal, was performed by employing a set of ecological indicators such as crustal enrichment factor, risk assessment code, risk indices for trace elements, and benzo[a]pyrene equivalent concentration for PAHs. Sequential analysis shows that the trace elements portion is the lowest for water-soluble and exchangeable fractions. The highest enrichment levels in FAs are noticed for As and Hg. Based on toxic trace elements content, FAs from TPPs represent a very high ecological risk, whereas fly ash from FBB poses a moderate ecological risk but has the highest benzo[a]pyrene equivalent concentration, indicating its increased carcinogenic potential. Lead isotope ratios for Serbian coals and FAs can contribute to a lead pollution global database.

Due to intensive urbanization, global warming, and increasing energy demands, the impact of urban heat islands is becoming more significant. This study investigates the contribution of vehicular emissions to air pollution and its effects on urban heat island intensity in a selected area of Belgrade, Serbia, between March and September 2015, using a combination of experimental measurements and numerical simulations. Furthermore, this study presents the results of the research on the impact of assessment of traffic-induced air pollution on the appearance of thermal islands in the urban environment, as well as the characterization of thermal islands and their quantification. This study quantifies the effects of traffic-related emissions and urban meteorological parameters on the intensity of the urban heat island by combining field measurements with a validated three-dimensional numerical model and shows that higher traffic density increases pollutant concentrations and cooling energy demand in buildings. The study includes experimental measurements of traffic intensity and modeling of gas emissions from major roads. Using long-term and short-term field measurements, concentrations of carbon dioxide and other pollutants were analyzed with meteorological parameters and their cumulative impact to assess their impact on local air quality. A three-dimensional numerical model for simulating the dispersion of pollutants has been developed, confirmed and validated by experimental data. The results highlight a direct correlation between traffic density and pollutant concentrations, emphasizing the need for strategic urban planning and sustainable transport policies to mitigate the effects of air pollution. A validated numerical model was used to simulate dynamic changes in temperature fields and carbon dioxide concentrations caused by vehicular emissions. The findings reveal that the Urban Heat Island Intensity (UHII) for the selected area in Belgrade reached peaks of up to 12 °C during the summer measurement period, with typical values in July ranging from 5 °C to 9 °C. Furthermore, the validated numerical model demonstrated that the removal of urban trees would lead to a local air temperature increase of 1.5 °C to 3 °C, quantifying the significant cooling potential of green infrastructure. These results highlight a direct correlation between traffic density, pollutant concentrations, and the intensification of urban heat islands, emphasizing the need for strategic urban planning. Furthermore, the findings reveal that increased traffic not only elevates air pollutant levels but also enhances the intensity of urban heat islands, leading to higher cooling energy demands in buildings. These insights are vital for developing effective mitigation strategies to improve the sustainability of urban environments and living conditions. These findings provide a clear directive for urban planners: the integration and preservation of green infrastructure is a highly effective UHI mitigation strategy, capable of reducing local temperatures by 1.5–3 °C. Furthermore, the results strongly support the implementation of targeted traffic management policies in dense urban cores as a dual strategy to improve air quality and reduce local thermal loads.

To achieve the optimum dust removal performance of an electrostatic precipitator, the flue gas should be distributed uniformly over its vertical cross-section. The flow in the upstream flue gas ducts has a significant influence on the downstream gas distribution in the chamber of the precipitator. This paper presents the results of homogeneity assessment of velocity distribution in the ducts and vertical cross-sections of the electrostatic precipitator of unit A1 at the Nikola Tesla thermal power plant in Obrenovac. The measurements confirmed that the reconstruction of the vertical chamber at the front of the precipitator, which was carried out during the overhaul in 2020, effectively solved the problem of the original asymmetric arrangement of the vertical flue gas ducts. Nevertheless, the analysis revealed poor homogeneity of the flow field through the chambers. Therefore, additional measures must be taken to increase the dust removal efficiency of the precipitator.

Coal combustion in large-scale power plants is a major source of atmospheric pollution, including SO₂, NO_x, particulate matter, and the halogen acids HCl and HF. Predicting HCl and HF emissions is challenging due to interactions among fuel composition, fly ash chemistry, combustion conditions, and flue gas dynamics. In this study, artificial neural network (ANN) models are developed from field experiments at the lignite-fired TPP “Kostolac B”. The models incorporate operational parameters (flue gas temperature and flow rate) and fuel/ash characteristics (moisture and total sulphur in coal and CaO content in ash) to estimate HCl and HF emissions. SHAP analysis identified key variables affecting halogen acid release. The developed ANN models achieved satisfactory predictive accuracy, with the test-set performances of RMSE = 2.05 mg/Nm³, R² = 0.80, and MAPE = 18.7% for HCl prediction, and RMSE = 3.23 mg/Nm³, R² = 0.83, and MAPE = 18.7% for HF prediction. SHAP analysis indicated that CaO content in fly ash and coal moisture are the primary drivers of HCl and HF emissions, while operating conditions and coal sulphur content influence emissions through non-linear interaction effects. The proposed ANN-SHAP framework provides a data-driven approach for emission prediction and interpretation, supporting decision-making in emission management.

Of all the fossil fuels in the world, the largest coal reserves are the most evenly distributed, and their mass exploitation ensures a stable and relatively low price on the international market, but coal contributes significantly to total greenhouse gas emissions. Reducing carbon dioxide emissions by increasing the energy efficiency of converting fossil fuels, especially coal, into electricity is known as Clean Coal Technologies. Particular attention is paid to low-grade coals with high moisture content, including lignite, which has significant reserves worldwide. Against this background, intensive efforts are being carried out to increase the energy efficiency of electricity generation from low-grade coal with high moisture content in the thermal plant by developing and introducing the process of pre-drying using the thermal energy available in the thermal plant. The drying process was investigated under fluidized bed conditions. Experimental investigations of the drying process in the fluidized bed were carried out at two different fluidization velocities and three different air temperatures measured at the front of the sample. The experimental results obtained and the influence of the above parameter values show that the drying rate of the sample increases with increasing temperature, while the drying time of the sample decreases.

Coal combustion is a major contributor to environmental pollution, releasing various harmful pollutants, including mercury, which poses significant risks to soil and water quality through atmospheric deposition. For this reason, some countries have established regulatory limits on mercury emissions from coal combustion, requiring the use of advanced pollution control technologies to capture and effectively reduce mercury emission. In this study, the mercury content in coal, coal ash samples and flue gas from the Kolubara A thermal power plant is determined. The results show that the mercury concentration in coal was 0.73 mg/kg, whereas the concentrations in fly ash and bottom ash were 0.02 mg/kg and 0.03 mg/kg, respectively. The mercury concentrations in coal and coal byproducts were in accordance with existing literature. In addition, the overall mercury content in flue gas was 38.73 µg/Nm³, falling within the permissible emission limit for thermal waste treatment in Serbia. The calculated mercury emission factor was below the lower limit specified in the Air Pollutant Emission Inventory Guideline of the European Monitoring and Evaluation of Air Pollutants (EMEP/EEA). These findings provide useful data for long-term environmental monitoring and regulation of mercury emission from coal combustion in Serbia.