Atmospheric Transport, a Major Pathway of Microplastics to Remote Regions

In recent years, marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas atmospheric microplastic transport has been largely overlooked. Here, we present the first global simulation of atmospheric transport of microplastic particles produced by road traffic (TWPs – tire wear particles and BWPs – brake wear particles), a major source that can be quantified relatively well. We find a high transport efficiency of these particles to remote regions, such as the Arctic Ocean (14%). About 34% of the emitted coarse TWPs and 30% of the emitted coarse BWPs (100 kt yr-1 and 40 kt yr-1 respectively) were deposited in the World Ocean. These amounts are of similar magnitude as the total estimated terrestrial and riverine transport of TWPs and fibres to the ocean (64 kt yr-1). Atmospheric transport of microplastics is thus an underestimated threat to global terrestrial and marine ecosystems and affects air quality on a global scale, especially considering that other large but highly uncertain emissions of microplastics to the atmosphere exist. High latitudes and the Arctic are highlighted as an important receptor of mid-latitude emissions of road microplastics, which may imply a future climatic risk, considering their affinity to absorb solar radiation and accelerate melting.