Microplastics in urban road dust: Sampling, analysis, characterization, pollution level, and influencing factors

Recently, microplastics (MPs) in stormwater have become an issue of global concern. MPs present in urban road dust are recognized as the dominant contributor to stormwater microplastic pollution. This paper comprehensively reviews the current knowledge on MPs in road dust, including sampling, analytical and detection methods, contaminant characteristics, influencing factors, pollution sources, and ecological risk, coupled with the further studies. MPs have been prevalent in road dust with an extremely high regional variability as there is various influencing factors such as population, land use type, traffic volume, and even climate. Highly intensive human activities can generally lead to higher levels of microplastic contamination. It is believed that the microplastic pollution in road dust has been underestimated, due to inefficient detection methods, especially for tiny MPs. Considering the significant differences in research methods between studies, the establishment of uniform sampling, analysis, and ecological risk assessment methods should be a priority.