Particles caused by tyre, brake and road surface wear are now responsible for the majority of traffic-related particulate matter and microplastics pollution. When stricter air quality limits come into force across the EU in 2030, it will be virtually impossible to comply with them without a reduction in wear-related emissions. As part of the new Graz University of Technology (TU Graz) Lead Project NExT – Non-Exhaust Emission Topics, researchers at TU Graz will be developing the necessary foundations for the reliable assessment and effective reduction of non-exhaust emissions over the next three years. To this end, interdisciplinary teams from five institutes under the project management of Cornelia Lex and Stefan Hausberger are conducting research into the formation of tyre, brake, road and rail wear particles. They are developing standardised, realistic test procedures for various vehicle classes and components as well as technical solutions that can significantly reduce emissions.

Decisive contribution to the reduction of non-exhaust emissions

TU Graz is funding the Lead Project NExT, in which 25 researchers and 6 technicians will be involved, with almost 1.9 million euros. “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,” says Andrea Höglinger, Vice Rector for Research at TU Graz. “The expected results of the NExT Lead Project will provide new momentum in basic research, which will help to further reduce transport-related emissions.”

Still no standard method for determining road wear emissions

The researchers are developing test methods with which both solid and volatile wear emissions can be completely captured and thus made measurable. This is the only way to assess emissions in real road and rail transport at all. Up to now, there has been no standard method for determining road wear, and tyre wear is only calculated from the weight loss of the tyres in relation to the distance driven. “Which and how many harmful ultra-fine particles are produced in the process is not recorded,” says co-project manager Cornelia Lex. “We therefore see a risk that manufacturers will only optimise their tyres 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.”

Development of highly sensitive sensors

“In order to measure and classify even the finest particles down to a size of 2.5 nanometres, 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, tyre and road wear, but also their morphology and chemical composition,” says co-project manager Stefan Hausberger. These findings serve as the basis for the development of technical solutions that can reduce emissions.

It is particularly important that the measurement results are transferable to real driving conditions. To this end, the researchers will further develop simulation models and validate them through physical tests and measurements in real driving situations, in which they will also take into account the influence of different driving styles and road conditions. In addition to road traffic, rail traffic, which also accounts for a significant proportion of non-exhaust emissions, will also be analysed.

Institutes of TU Graz involved in the Lead Project NExT:

• Institute of Thermodynamics and Sustainable Propulsion Systems
• Institute of Automotive Engineering
• Institute of Electrical Measurement and Sensor Systems
• Institute of Electron Microscopy and Nanoanalysis
• Institute of Structural Durability and Railway Technology

Lead Projects at TU Graz

Since 2015, TU Graz has awarded special funding for multidisciplinary Lead Projects. By funding such projects, cutting-edge research areas are further developed and the academic profile of TU Graz strengthened. The selection of Lead Projects takes place in a two-stage process. Researchers first submit a preliminary proposal, which is assessed by the Rectorate. The most promising projects will be invited to submit a full proposal, which will be presented to a high-calibre international panel at a hearing.

Lead Projects funded to date

• Digitalisation of Biotechnology (coordination: Robert Kourist, Institute of Molecular Biotechnology)
• Mechanics, Modelling and Simulation of Aortic Dissection (coordination: Gerhard Holzapfel, Institute of Biomechanics; Katrin Ellermann, Institute of Mechanics)
• Porous Materials @ Work for Sustainability (coordination: Paolo Falcaro, Institute of Physical and Theoretical Chemistry)
• Dependable Internet of Things (coordination: Kay Uwe Römer, Institute of Technical Informatics)