Assessment of Traffic-Induced Air Pollution and Its Effects on Intensity of Urban Heat Islands

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.