14 July 2020
Atmospheric transport of microplastic pollution from roads
As the production rate of new plastic products continues to increase, ever greater quantities evade waste collection and recycling. In recent years, marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas atmospheric microplastic transport has been largely overlooked.
Nikolaos Evangeliou and colleagues combine a global quantification of road microplastics (produced from tyre wear and brake wear) with simulations of atmospheric transport pathways to determine the trajectory of these pollutants. Road microplastic emissions currently constitute 30% of microplastic pollution, the majority of which comes from densely populated regions like the eastern US, Northern Europe and the heavily urbanized areas of Southeast Asia. The authors found that larger particles were deposited close to the source of production. Conversely, microplastics that are 2.5 micrometers and smaller in size were transported further afield. They estimate that 52,000 tonnes per year of the small size microplastics end up in the world’s oceans. However, around 14% (20,000 tonnes per year) ends up on remote snow- and ice-covered surfaces. The authors note that this is concerning for sensitive regions, such as the Arctic, because the dark particles decrease surface albedo (the amount of sunlight reflected from the Earth’s surface) and could hasten melting.
This research work made use of detailed estimates of the global emissions of particulate matter arising from tyre wear and brake wear calculated with the AIR Program's GAINS model. The resulting paper is the latest in a growing line of modelling studies that have been based on global emission estimates generated in the course of the ECLIPSE and subsequent projects.
Based on a press release prepared by Nature Research.
Reference
Evangeliou N, Grythe H, Klimont Z , Heyes C , Eckhardt S, Lopez-Aparicio S, & Stohl A (2020). Atmospheric transport is a major pathway of microplastics to remote regions. Nature Communications 11, 3381.
DOI: 10.1038/s41467-020-17201-9