The atmospheric transportation around the world of microplastics produced by road traffic is modelled in a paper in Nature Communications. The study finds that microplastic particles are transported to remote regions, including the Arctic. Estimates suggest that the total amount of these particles which end up in the oceans as a result of airborne delivery is of a similar size to that deposited by rivers.
As the production rate of new plastic products continues to increase, ever greater quantities evade waste collection and recycling. However, the ecological and environmental consequences of rising plastic pollution, and the routes they take to get there, are poorly understood.
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.
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