Microplastics in road dust and surrounding environment: Sources, fate and analytical approaches

Microplastic pollution is a growing environmental concern worldwide, and roadsides have been recognized as a reservoir for microplastic accumulation. The main sources of microplastics on the road dust and roadside are tire and road wear particles and plastic litter. Once released to the road surface, these are combined with other contaminants released via vehicle exhausts and particulate matter on the road surfaces. This review aimed to assess roadside microplastics' sources, abundance, characteristics, and dispersion pathways. Further, this review critically discusses existing analytical techniques for identifying roadside microplastics and their limitations. Microplastics in the roadside are mainly identified using spectroscopic techniques; however, using specific markers to identify microplastics in roadside soil is rather common and effective due to additive-based interferences with infrared radiation. The health impacts of roadside microplastics are under-studied, necessitating more studies and standardized methods for their monitoring and analysis.