Until now, emissions from tire, brake, and road surface wear—known to pose significant health risks—have not been adequately measured. Researchers at TU Graz aim to change that with the Lead Project NExT, where they’re developing precise analysis methods and realistic testing procedures.
Cornelia Lex from the Institute of Automotive Engineering and Enis Ketan from the Institute of Thermodynamics and Sustainable Propulsion Systems at TU Graz at the tyre test bench. Image Credit: Lunghammer - TU Graz
Wear particles from tires, brakes, and road surfaces have now become the leading source of traffic-related particulate matter and microplastic pollution. With stricter EU air quality limits set to take effect in 2030, reducing these wear-related emissions will be essential for compliance.
Over the next three years, TU Graz’s new Lead Project NExT (Non-Exhaust Emission Topics) will lay the groundwork for accurately assessing and mitigating these emissions. The project brings together interdisciplinary teams from five TU Graz institutes, under the leadership of Cornelia Lex and Stefan Hausberger, to investigate how particles are formed and to develop standardized, realistic test procedures for different vehicle types and components. They’re also working on technical solutions to help curb emissions at the source.
Decisive Contribution to the Reduction of Non-Exhaust Emissions
TU Graz is investing nearly €1.9 million in the Lead Project NExT, which involves 25 researchers and 6 technicians.
The Lead Projects are closely linked to TU Graz's Fields of Expertise, in which researchers from various disciplines work together on the pressing issues of our time. Sustainable mobility is one of the key research areas that we are further strengthening with this substantial project funding. The expected results of the NExT Lead Project will provide new momentum in basic research, which will help to further reduce transport-related emissions.
Andrea Höglinger, Research Vice Rector, TU Graz
Still No Standard Method for Determining Road Wear Emissions
Researchers are working on test methods capable of capturing both solid and volatile wear emissions in full—making them measurable for the first time. This is essential for accurately assessing emissions in real-world road and rail transport. Until now, there has been no standardized method for measuring road wear. Tyre wear, for example, is typically estimated based on the weight loss of the tyres relative to the distance driven.
Which and how many harmful ultra-fine particles are produced in the process is not recorded. We therefore see a risk that manufacturers will only optimize their tires in terms of mass loss, but this may be accompanied by an increase in emissions of ultra-fine particles or the use of environmentally harmful components.
Cornelia Lex, Co-Project Manager, TU Graz
Development of Highly Sensitive Sensors
In order to measure and classify even the finest particles down to a size of 2.5 nm, we will develop highly sensitive sensors and examination methods with which we can precisely determine not only the number and size of the particles caused by brake, tire and road wear, but also their morphology and chemical composition.
Stefan Hausberger, Co-Project Manager, TU Graz
Ensuring that measurement results reflect real-world driving conditions is a key priority for the research team. To achieve this, they plan to enhance existing simulation models and validate them through physical testing and on-road measurements. These tests will also factor in variables like driving style and varying road conditions, which can significantly influence wear emissions.
The scope of the study isn’t limited to road traffic—rail transport will also be examined. Despite often being overlooked, rail accounts for a notable share of non-exhaust emissions and will be an important part of the overall analysis.