Modeling and Measurements of Traffic-Related PM10, PM2.5, and NO2 Emissions Around the Roundabout and Three-Arm Intersection in the Urban Environment

In recent decades, road transport has become one of the dominant factors shaping environmental conditions, with both beneficial and adverse consequences. While transport infrastructure facilitates access to essential services and supports societal well-being, vehicular emissions remain a major source of air quality degradation. Among the pollutants released, nitrogen dioxide (NO2) and fine particulate matter (PM2.5) are of particular concern due to their adverse health effects, especially in densely trafficked urban areas. Pollutant levels are determined not only by traffic intensity but also by external influences such as meteorological conditions and roadway design. This study examines how different intersection configurations affect ambient concentrations of PM10, PM2.5, and NO2. Field monitoring and dispersion modeling were carried out for a three-arm intersection and a roundabout. NO2 concentrations were quantified using a reference chemiluminescence method, while PM10 and PM2.5 were measured with an optical aerosol spectrometer. Traffic flow characteristics associated with each intersection geometry were simulated in PTV Vissim, and pollutant dispersion patterns were subsequently analyzed using the CadnaA modeling environment. Field measurements revealed lower PM concentrations (reduction in PM10, PM2.5–10 and PM2.5 concentration—30.1%, 45.1% and 22.8%) and higher NO2 concentrations (increase in NO2 concentration—143.3%) at the roundabout.