Suspended Airborne Microplastics in Urban Roadside Environments of Cagayan De Oro City, Philippines: Abundance, Characteristics, and Polymer Composition

Atmospheric microplastics are increasingly recognized as emerging contaminants in urban air, yet evidence from Philippine cities outside Metro Manila remains scarce. This study investigated polymer-confirmed suspended airborne microplastics across four urban roadside environments in Cagayan de Oro City, in southern Philippines: C.M. Recto Avenue, J.R. Borja Street, Gaabucayan Street, and Nazareth Street. Atmospheric particles were collected from 12 roadside stations, or three from each site, using a respirable dust sampler during a standardized mid-day sampling period, then subjected to alkaline digestion, microscopic examination, and ATR-FTIR confirmation. Of 99 suspected particles, 44 were verified as synthetic polymers and included in the final analysis. Mean atmospheric microplastic concentrations ranged from 0.0079 to 0.0212 items m⁻³, with J.R. Borja Street showing the highest concentration and Nazareth Street the lowest. Abundance did not differ significantly among roads, whereas particle shape, color, and polymer composition varied significantly, while size-class distribution did not. Fibers were the dominant morphology (56.8%), transparent particles were the most common color class (52.3%), and polypropylene and polyethylene terephthalate were the predominant polymers. These findings confirm the presence of atmospheric microplastics across roadside environments in Cagayan de Oro City and indicate that spatial variation is more evident in particle characteristics than in overall abundance.