The Tire Industry Project (TIP) has announced the publication of a scientific study that introduces an advanced model for understanding the movement and concentrations of tyre and road wear particles (TRWP) in land and freshwater. The mass balance model as it is known presents a methodology to track and predict with high spatial granularity how TRWP move through watersheds – areas of land where rainfall and surface water drain into a river, lake or estuary – across diverse climates and regions.
TRWP are particles unintentionally generated at the frictional interface between the tire and roadway during vehicle use. As scientific and regulatory interest in these particles grows, tools that can generate reliable TRWP data are an essential prerequisite to understanding how they move through different environments. TRWP flow through waterways in particular remains an understudied topic.
The newly released model is designed to use global and local datasets and open-source modelling frameworks such as the ERA5 global climate dataset by the Copernicus Climate Change Service and the Wflow catchment hydrology model by Deltares, a research institute. Validated against field measurements from watersheds on three distinct continents — the Seine River basin in France, the Chesapeake Bay basin in the US, and the Yodo River basin in Japan – the modelling approach is applicable at a watershed-scale in regions with varying watershed characteristics, climates and stormwater management systems.
Results of applying the model to the three above watersheds show substantial differences in how much TRWP reach surface waters, with amounts reaching estuaries ranging from 2% to 18%, depending on factors such as watershed basin size, level of urbanisation, climate and stormwater management infrastructure. The study further indicates that factors like improvements in stormwater systems can reduce TRWP transport to surface waters by up to a half, underscoring the value of infrastructure-based mitigation measures.
The newly published model is a refinement of earlier work and extends the modelling approach to a global scale. The next phase of development is already underway, aiming to make the model accessible to users beyond the scientific community.
The study was authored by Jos van Gils (Deltares), Hélène Boisgontier (Deltares), Lora Buckman (Deltares), Steffen Weyrauch (Helmholtz Centre for Environmental Research—UFZ), Thorsten Reemtsma (UFZ and University of Leipzig), Timothy R. Barber (ERM), and Kenneth M. Unice (TRC Companies).