Determination of Microplastics Presence in Suspended Particulate Matter in the Air. Case Study: Zpu 99 in the Chapinero Locality, Bogotá, Colombia

Abstract The dependence on the indiscriminate use of plastics has had a negative impact on the environment. Despite studies on macro- and microplastics in coastal areas, empirical evidence in urban inland and high-altitude regions remains scarce, especially in Latin American cities, where atmospheric dynamics differ from those of coastal regions. In light of this scenario, there is an urgent need for research focused on the presence, concentration, and behaviour of airborne microplastics in urban outdoor environments. The objective of this research, which was conducted in Zonal Planning Unit 99 in Bogotá, Colombia, was to determine the presence, concentration, and characteristics of microplastics and evaluate their relationship with physicochemical and environmental variables using a high-volume air sampler. The filters were processed by chemical digestion with HCl and H 2 O 2 in order to remove organic matter. Subsequently, the microplastics were dried and visually analysed under a stereoscope, classified by shape, colour, and size. They were then confirmed as plastics using morphological criteria and the hot needle test. A total of 211 microplastic were found across two monitoring points, with differences observed in both the quantity and colour of the fibres. These findings emphasize the importance of addressing microplastic contamination in urban environments and underscore the necessity of implementing measures to reduce plastic pollution. Although no statistically defined hotspots were identified at this scale, the constant presence of microplastics in all samples indicates widespread contamination, highlighting the need for continuous monitoring of this emerging pollutant, particularly in high-altitude urban settings where data are still limited.