fig4

Figure 4. Schematic diagram of TWP environmental migration: the migration process of TWPs from emission sources (e.g., roads) through pathways such as runoff and sweeping into environmental media including freshwater systems, landfills, sediments, terrestrial environments, estuaries, oceans, and polar regions, while also encompassing atmospheric transport and deposition pathways. TWP: Tire wear particle; WWTP: wastewater treatment plant.