Road-associated microplastics (RAMP) in metropolitan areas of the Philippines: potential source of suspended plastics in the air

Abstract Microplastics (MPs) with sizes ranging from 1 mm − 5 mm are increasingly seen as a new source of air pollution because of the contaminants they take in and the interactions they have with other pollutants. This study investigates dust size fractionation based on weight and the abundance of suspected MPs in selected metropolitan areas in the Philippines-Metro Manila and Metro Cebu. The results of the study show that among the sampled dust particles, those with a grain size of 250 µm are the most abundant, followed by 45 µm and 150 µm, and 125 µm as the lowest. Additionally, the occurrence of roadside-associated microplastics (RAMPs) in different sampling stations revealed varying numbers and densities of microplastics in Metro Manila and Metro Cebu. The highest counts of RAMP were found in Taguig City, Metro Manila, and Apas in Cebu City, Metro Cebu. The most abundant shape is fiber, and blue is the most prevalent color. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) analysis results show that polypropylene is the most common polymer type identified. The findings of this study contribute to understanding the distribution and characteristics of dust particles and microplastics in the studied areas, highlighting the environmental implications of plastic pollution especially that this MPs could very be a potential source of suspended MPs in the air. Hence, future research should focus on exploring the sources, transport mechanisms, and potential ecological impacts of these microplastics.