Challenges in Quantifying Tire Wear Particle Emissions on an Outer Drum Test Bed

Tire wear is a major source of microplastics and airborne particles (<10 µm), posing environmental and health risks. Accurate quantification is essential for regulatory control. This study develops a method to measure tire wear and tire wear particles on an outer drum test bed while achieving realistic wear rates. A key challenge is the necessity of de-gumming methods, such as talcum powder, to prevent tire adhesion to the drum. However, this complicates emission measurements. The test bed at TU Graz features an enclosure with flow-optimized baseplates and AirKnifes to minimize background emissions. The sampling system, compliant with GTR-24 (brake wear), includes two AVL Particle Counters, two PM-Samplers, and an ELPI+ for size distribution analysis. Results show that background emission reduction is critical for accurate measurement. The de-gumming method increased tire wear rates by a factor of 10 but introduced additional particle sources. Size distribution analysis revealed clear differences between talcum and tire wear particles, with talcum particles being coarser. The discrepancy between PM10 and PM2.5 mass further supports this distinction. However, distinguishing between these sources remains a challenge, as talcum significantly contributes to mass measurements. Without de-gumming, wear rates are unrealistically low, highlighting the need for alternative methods. This study quantifies tire wear and tire wear particles under controlled conditions while addressing key methodological challenges. Future research should focus on refining measurement techniques to better isolate tire wear particles and assess their impact on the environment and human health