TIP-backed study urges standardisation in tire wear emissions research

Geneva, Switzerland – A Tire Industry Project (TIP) backed scientific review is calling for stronger research methods and harmonised testing to improve the measurement and assessment of tire wear emissions.

The three-part 'state of knowledge' review, called Tire wear emissions during the use phase*, is said by the tire industry body to be “the most comprehensive [study] of its kind.”

The independently authored series analyses more than 850 peer-reviewed publications from the past 40 years on the subject of tire wear emissions, said TIP in a 6 Aug statement.

According to TIP, the review has concluded that current studies on subject are often “fragmented, inconsistent and inconclusive” due to differences in methodology and assumptions.

“The topic of tire wear emissions is extremely complex, multi-dimensional, and unfortunately only partially understood,” said co-author Dr Stephan Wagner.

Stressing that “notable progress” has been made in recent decades, Wagner said “significant knowledge gaps and inconsistencies prevent a full understanding of their [tire] behaviour and impact.”

Wagner warned that without closing those gaps, “there is a growing concern that decisions about tire emissions could be based on incomplete science”.

The first paper in the series is focused on characterising tire wear emissions, which can take the form tire and rubber wear particles (TRWP), volatile compounds and dissolved or “leachable” materials.

According to the review, factors such as driving style, speed, braking, cornering, vehicle load and road surface influence emissions.

The paper proposed a “conceptual exposure model” to trace where emissions occur, how they disperse and potential exposure pathways, alongside a “tiered measurement framework” to standardise TRWP testing.

The second paper reviewed environmental risk assessment, finding that “current data is insufficient” for a complete evaluation, particularly for leachables and volatiles.

The paper called for harmonised testing protocols and suggests adapting existing microplastics frameworks for tire wear emissions.

The authors proposed a “tiered hazard assessment” starting with lab-generated materials and moving to real-world studies.

The third, expected later this year, will examine potential human health impacts.

“We hope that these papers will encourage the scientific community and serve as a catalyst for further research and standardisation,” said Wagner commenting on the findings.

*The 'state of knowledge' papers and supporting materials are available at: https://tireparticles.info/our-research#sokpaper1 and https://tireparticles.info/our-research#sokpaper2