Tire & Road Wear Particles

What are tire and road wear particles?

TRWP are tiny debris produced by the necessary friction between tires and road surface; they are a mixture of tire tread and road pavement material.

Are TRWP microplastics? There is no globally accepted definition of microplastics. However, our focus is not on how TRWP may or may not be categorized, but to study them to learn more about any potential impacts they may have on human health and the environment.

USTMA support for research

USTMA members are committed to reducing their environmental footprint and providing safe, high quality products.

Tires are one of the most important components of a car. In addition to supporting the vehicle’s weight, absorbing impacts and withstanding various weather conditions, tires connect the car to the road. That is why the grip between a tire and the road surface is so essential to tire safety and performance. The friction between tires and roads is needed for a tire’s grip on the road, but also leads to abrasion of both tire and road, producing TRWP. Studies supported by World Business Council for Sustainable Development’s Tire Industry Project have found that TRWP are unlikely to have adverse effects on human health and the environment. USTMA supports additional research by TIP to gain a deeper understanding of any potential human health or environmental risks associated with TRWP.

World Business Council for Sustainable Development’s Tire Industry Project

Since 2005, the World Business Council for Sustainable Development (WBCSD) Tire Industry Project (TIP) drives research on potential human health, environmental and social impacts of tires throughout their lifecycle. The focus of TIP’s work is on filling knowledge gaps about TRWP. TIP has a working group dedicated to TRWP whose mandate is to ensure a scientific approach to the study of TRWP pathways.

TIP has supported studies of TRWP in various environments, including air, water, and sediment. Based on a comprehensive risk assessment, the peer-reviewed studies found no adverse effects to human health or the environment. These studies found that TRWP presented a low toxicity in freshwater environments and low levels of TRWP in airborne particulate matter, from high traffic locations in Europe, Japan and the United States. You can find links to these studies on the TIP website at: https://www.wbcsd.org/Sector-Projects/Tire-Industry-Project/Resources/Tire-Road-Wear-Particles-Papers

Specifically, studies into airborne TRWP have concluded that TRWP make a relatively low contribution to particulate matter of the size fractions of most significance to human health (example 1example 2). Additionally, studies suggest that TRWP is unlikely to pose risk to humans through airborne exposure.

Continued TIP-sponsored research includes extended scanning of TRWP presence in air, studying the degradation of TRWP in the environment, modelling TRWP fate and transport in all relevant environmental compartments (i.e., air, rivers, soil, oceans), and investigating the impact on organisms of long-term exposure to TRWP.

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