Atmospheric transport is a major pathway of microplastics to remote regions

S Eckhardt,C Heyes,A Stohl,Z Klimont,H Grythe,N Evangeliou,S Lopez-Aparicio

doi:10.1038/s41467-020-17201-9

Abstract

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 global simulations 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 efficiencies of these particles to remote regions. 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 direct and riverine transport of TWPs and fibres to the ocean (64 kt yr−1). We suggest that the Arctic may be a particularly sensitive receptor region, where the light-absorbing properties of TWPs and BWPs may also cause accelerated warming and melting of the cryosphere.

Highlights

In recent years, marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas atmospheric microplastic transport has been largely overlooked
The two methods were compared in detail (Supplementary Fig. 1) showing that tyre wear particles (TWPs) emissions are very similar (0.25–32 t year−1 per grid cell); we report the geometric average
Annual global deposition of road microplastics in PM2.5 and PM10 size bins estimated with FLEXPART version 10.4 model

Summary

Introduction

Marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas atmospheric microplastic transport has been largely overlooked. We present global simulations 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. 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 direct and riverine transport of TWPs and fibres to the ocean (64 kt yr−1). Kole et al.[14] reported global average emissions of tyre wear particles (TWPs) of 0.81 kg year−1 per capita, about 6.1 million tonnes (~1.8% of total plastic production). Emissions of brake wear particles (BWPs) add another 0.5 million tonnes. BWP emissions depend on the bulk friction material[23,26], on the frequency and severity of braking[27], speed, weight, condition and maintenance of the automobile[28] and the environmental conditions[23,29,30]

Methods

Results

Conclusion