Tire Abrasion as a Major Source of Microplastics in the Environment

Frank Sommer; Volker Dietze; Anja Baum; Jan Sauer; Stefan Gilge; Christoph Maschowski; Reto Gieré

doi:10.4209/aaqr.2018.03.0099

Tire Abrasion as a Major Source of Microplastics in the Environment

$BSE images of crushed granite and its mineral components from the wearing course: (a) Composite of minerals typical of granite, held together with bitumen; size fraction 10–20 µm deq, (b) Single mineral, size fraction 20–40 µm deq, and (c) Single mineral, size fraction 40–80 µm deq.$

Frank Sommer¹, Volker Dietze², Anja Baum³, Jan Sauer³, Stefan Gilge², Christoph Maschowski¹, Reto Gieré ⁴

¹Institute for Geo- and Environmental Natural Sciences, Freiburg University, 79104 Freiburg, Germany
²Air Quality Department, Research Center Human Biometeorology, German Meteorological Service, 79104 Freiburg, Germany
³Federal Highway Research Institute, 51427 Bergisch Gladbach, Germany
⁴Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104-6316, USA

Received: March 17, 2018
Revised: June 22, 2018
Accepted: June 24, 2018
Download Citation: ||https://doi.org/10.4209/aaqr.2018.03.0099

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Cite this article:
Sommer, F., Dietze, V., Baum, A., Sauer, J., Gilge, S., Maschowski, C. and Gieré, R. (2018). Tire Abrasion as a Major Source of Microplastics in the Environment. Aerosol Air Qual. Res. 18: 2014-2028. https://doi.org/10.4209/aaqr.2018.03.0099

HIGHLIGHTS

Microplastic from tires turns up everywhere and is a potential environmental hazard.
Over 90% of the super-coarse particles on busy roads are tire, road and brake wear.
No PM_10-80 tire-core particle without road-dust contamination was found on the roads.
Tire-wear particles accumulate a varying amount of road dust encrustment.
Traffic speed, traffic mode and traffic fleet determine particle size of brake wear.

ABSTRACT

Traffic-related non-exhaust particulate matter mainly consists of tire wear, brake wear, and road wear. For this study, passive-samplers were placed near highly frequented roads in industrial, agricultural, and urban environments with the aim of collecting and characterizing super-coarse (> 10 µm) airborne particles. Single-particle analysis using SEM-EDX was conducted on more than 500 particles with nearly 1500 spectra to determine their size, shape, volume, and chemical composition. The ambient aerosol near all studied roads is dominated by traffic-related abrasion particles, amounting to approximately 90 vol%. The majority of the particles were composites of tire-, road-, and brake-abrasion material. The particle assemblages differed in size distribution, composition, and structure depending on driving speed, traffic flow, and traffic fleet. Our study documents that tire wear significantly contributes to the flux of microplastics into the environment. A decrease in the release of this abrasion material, however, is unlikely in the near future.

Keywords: Microplastics; Tire wear; Road wear; Brake wear; SEM-EDX analysis; Chemical composition.