GENEVA, April 30, 2026 /3BL/ – The final installment of a three-part scientific State of Knowledge (SoK) paper series on tire wear emissions concludes that, while the understanding of tire wear emissions has advanced, current data to quantify human health impacts attributable to tire wear emissions remains inconclusive.
The review finds that differences in sampling approaches, detection techniques and analytical methodologies limit reliable comparison across studies and prevent robust risk assessment. In addition, based on the peer-reviewed literature studied, tire wear particles constitute only a small part of the overall airborne particulate matter, with similar or less potent effects compared to other particulate matter fractions.
Supported by the Tire Industry Project (TIP), part of the World Business Council for Sustainable Development (WBCSD), the SoK series represents the most comprehensive review of global science on tire wear emissions to date, analyzing more than 850 peer-reviewed scientific publications.
State of Knowledge series: Key findings from Paper 3
Independently authored by Kathrin Müller, Julie Panko, Kenny M. Unice, and Dr. Stephan Wagner, the paper Impacts of Tire Wear Emissions Compared to the Impacts of PM2.5 and PM10 on Humans reviews existing scientific knowledge on human exposure to tire and road wear particles (TRWP) and tire-related chemicals, concluding that:
- Tire wear particles make up only a small share of airborne particulate matter, typically less than 5% of PM 2.5 and PM 10 in urban environments.
- Toxicological studies to date do not show TRWP to be more harmful than general ambient particulate matter. Available in vivo and in vitro data indicates effects that are similar to or less potent than other airborne particle types.
- Despite growing interest, scientific evidence on human exposure to TRWP remains limited and inconclusive. Chemicals that are used in tire manufacturing are detectable in human body fluids, but their sources and exposure pathways have not been clearly linked specifically to tires, as many of these chemicals are used in a range of other applications.
- A major barrier to drawing firm conclusions is the lack of consistent global methods for sampling, analyzing, and characterizing tire wear emissions. Variability in methodologies across studies limits meaningful comparison and robust exposure or risk assessment.
Call for coordinated research efforts
As a result, the authors of the papers call for greater harmonization of research methodologies to improve identification, measurement and attribution of tire wear emissions. This need for coordinated efforts aligns with the conclusions of SoK Papers 1 and 2, which were published in 2025 and examined the characterization and quantification of tire wear emissions and their potential impacts on the environment.
The authors recommend that future research should identify potential exposure pathways and examine relevant health outcomes, including potential chronic effects, under realistic exposure conditions covering urban and suburban populations across different regions worldwide.
Dr. Stephan Wagner, one of the leading researchers of Paper 3, said: “Tire wear emissions are a complex topic that we still only partly understand, especially in relation to human health. While research has advanced our understanding of TRWP, the current data simply isn’t robust enough to quantify any potential health risks specifically linked to tire wear. Looking forward, cross-stakeholder collaboration is fundamental to making rapid progress. By aligning methods, sharing data, and focusing on real-world studies, we can build a stronger, more consistent evidence base to inform future decisions.”
Notes:
The State of Knowledge papers and supporting materials are available at https://tireparticles.info/our-research#sokpaper1, https://tireparticles.info/our-research#sokpaper2 and https://tireparticles.info/our-research#sokpaper3
- Kathrin Müller is a PhD Researcher at the Institute for Analytical Research (IfAR) at Hochschule Fresenius University of Applied Sciences in Idstein, Germany. Her PhD research is on the analysis of tire and road wear particles as environmental contaminants focusing on the identification of tire-borne environmental water contaminants.
- Julie Panko is Principal Scientist and Senior Vice President at ToxStrategies, a scientific consulting firm in the United States. She has more than 30 years of experience conducting and managing a wide variety of occupational, environmental, and consumer health risk assessments, including applied research regarding the potential for environmental impacts of tires throughout their lifecycle from manufacturing through end of life.
- Kenny Unice is Principal Computational Health Scientist at TRC Companies, Inc since 2026. Formerly a Principal Health Scientist and applied researcher at Stantec, he has more than 20 years’ experience investigating and driving understanding of how chemicals travel, persist or change in the environment to impact organisms and ecosystems.
- Dr. Stephan Wagner is Head of the Institute for Analytical Research at the Hochschule Fresenius University of Applied Sciences in Idstein, Germany. He is an expert in the analysis and fate of anthropogenic materials such as tire and road abrasion particles, micro and nano plastics, nano materials as well as organic trace contaminants in the (urban) water cycle.
