<![CDATA[Vehicular activity along urban toll road corridors contributes to particulate matter emissions that degrade air quality and increase public health risks, particularly respiratory and cardiovascular disorders. Roadside greenbelts are considered a nature-based solution for reducing airborne particles; however, comparative evaluations of roadside tree species for PM2.5 and PM10 mitigation remain limited. This study evaluated the reduction performance of three commonly planted roadside tree species, namely Lagerstroemia speciosa, Gmelina arborea, and Mimusops elengi, along the Jagorawi Toll Road. Particulate concentrations were measured in three vegetated plots and one non-vegetated control plot on 26, 28, and 30 April 2025 using calibrated Dienmern DM72B digital air quality detectors. Measurements were conducted simultaneously at 0, 10, and 30 m sampling points, with the 0 m point located at the first roadside tree row, approximately 5 m from the road edge. Leaf Area Index (LAI), leaf particulate retention capacity, microclimate, and traffic volume were also recorded. Vegetated plots reduced PM2.5 and PM10 concentrations by 30.82% and 29.23% on average, respectively, compared with the control at the same sampling distances. The plot dominated by M. elengi showed the largest average reduction, supported by the highest LAI value (2.1639) and leaf retention capacity (0.20 mg/cm²). These findings indicate that dense, high-LAI roadside tree canopies can improve PM2.5 and PM10 mitigation. However, species effects should be interpreted together with planting structure and site conditions. This study supports prioritizing high-LAI and dense-canopy species in roadside greenbelt planning. Keywords: Jagorawi toll road, particulate matter, PM2.5, PM10, roadside greenbelts]]>
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