Revealing region-specific drivers of tire and road wear particle composition and sources in road dust from two western Chinese cities

Summary

Tire and road wear particles (TRWP) accumulate in urban road dust, forming a potential exposure pathway for citizens. However, the driving factors for the generation and distribution of road TRWP with regional characteristics require more in-depth and comprehensive exploration. This study developed a comprehensive TRWP analysis framework based on a weight-of-evidence approach, which aided in exploring tire wear behavior. The methodology was applied to explore the occurrence patterns of road TRWP in two western Chinese cities with distinct regional characteristics. All urban roadway types with different uses may present potentially high tire wear, characterized by TRWP number abundance (20 μm-5 mm) of 2948–70,235 particles/m2 and mass concentration (2 μm-5 mm) of 3.8–108.5 mg/m2. Rubber composition analysis indicated that TRWP contained 37.8 % elastomer and 23.8 % mineral crusts. Tire wear source analysis revealed that heavier motor vehicles were more likely to generate larger TRWP particles (3–5 mm). Redundancy analysis revealed that parking and stop-star intensities, rather than traffic variables, were the primary factors influencing TRWP distribution (P < 0.05). Meanwhile, roadway roughness and stormwater runoff discharge had a superimposed effect on TRWP accumulation. The results offer new insights for TRWP emission characteristics under urban functional roads and specific traffic patterns with regional characteristics.