T149 Urban Geochemistry

Tuesday, 6 November 2018
8:00 AM - 12:00 PM
Room 135

TIRE-WEAR PARTICLES AS A MAJOR COMPONENT OF MICROPLASTICS IN THE ENVIRONMENT

Paper number: T149-1
Program: Technical Sessions
Time: 8:00 AM – 8:15 AM

Authors

Abstract

Particulate matter (PM) pollution in urban areas not only affects morbidity and mortality, but also vegetation and ecosystems. A series of measures succeeded in reducing exhaust emissions from traffic, but this is not the case for brake-, tire-, and road-wear particles. Tire-wear particles are a dominant component of the microplastics that pollute rivers, lakes, and oceans.

Our study focuses on non-exhaust airborne particles in the super-coarse mode (PM10-80) generated by traffic along highly frequented German roads with different traffic mode and vehicle velocities. Particles were analyzed individually by automated transmitted-light microscopy (TLM). Our TLM method allows for the determination of a number particle settling rate of the “total” atmospheric particle load, with subsequent calculation of the total ambient aerosol mass concentration [1]. It also allows for the differentiation by particle type (e.g., opaque vs. transparent) and size, which is then used to calculate the size-fractionated mass concentration of these particles [2].

To obtain additional details on the particles (size, shape, volume, chemical composition) we further used SEM-EDX, which enabled us to clearly distinguish between the different types of non-exhaust traffic particles as well as those from other sources. Our SEM-EDX results for more than 500 particles revealed that along busy roads, >90 vol% of all PM10-80 consists of materials produced through the abrasion of tires, road surface and brakes. Once deposited on the road surface, tire-abrasion particles develop an encrustment of varying magnitude, which itself consists of particles derived from the wearing course, brakes and brake pads, and of other road dust. Tire-derived microplastics, thus, not only consist of the original rubber core with its various chemical additives but also of potentially hazardous metals and metalloids contained in the attached brake-abrasion particles. These additional materials present in the encrustment, thus, increase the potential of environmental damage resulting from tire-wear particles.

References

[1] VDI 2119 (2013) ICS: 13.040.01. Beuth Verlag, Berlin.

[2] Dietze et al. (2006) Gefahrstoffe - Reinhaltung der Luft (Air Quality Control) 66.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-319219

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