Abstract
Abstract Despite the growing concern surrounding airborne microplastics (AMPs), their size-dependent behavior in tropical urban environments remains poorly understood. This study provides a preliminary assessment of the concentration, polymer composition, morphology, and size-segregated aerodynamic distribution of AMPs in Bandung, Indonesia. Size-segregated aerosols collected during the rainy season were analyzed using a micro-Fourier transform infrared attenuated total reflection imaging approach. The mean AMP concentration was 6.81 particles m⁻³, with polyethylene accounting for 93.6% of identified particles, and AMPs detected across all size fractions. A discrepancy was observed between physical particle size (maximum Feret diameter) and aerodynamic classification, as many particles exceeded the nominal cut-off diameters of their sampling stages, indicating the influence of particle shape and density on aerodynamic behavior. Morphological analysis showed that fragments dominated (89%), suggesting that secondary fragmentation is the primary formation pathway of AMPs in the study area. These findings highlight the critical importance of integrating size-segregated aerodynamic sampling with morphological and chemical characterization to assess the atmospheric transport and potential human health risks of AMPs in tropical urban environments. Graphical Abstract