Tire Wear Emissions
Particulate Matter (PM10) emissions are a notably harmful part of traffic-related air pollution. So far, little attention has been paid to Non-Exhaust Emissions (NEE), which are not yet legally regulated and mainly consist of tire, brake, and road abrasion. Tire wear alone currently causes more than a quarter of all traffic-related PM10 emissions. This share will increase significantly as electrified vehicles gain market share. The investigation and quantification of tire emissions are therefore of great relevance with regard to health effects and environmental damage. However, the formation of tire abrasion depends on a large number of complex influencing factors and their interaction. Current efforts to define a standardized test procedure for determining and limiting tire wear are therefore moving in the direction of extensive road trips in convoys and differential measurement of the total tire mass. This procedure is not only extremely time-consuming for each type of tire to be tested but is also dependent on many influencing factors and uncertainties. It can therefore be assumed that the wear measurement due to weight loss will soon be augmented or replaced with a procedure for reproducible particle emission measurement. For this reason, the TIRES project is investigating fundamental issues that pave the way for a representative, time-saving, and reproducible test bed procedure using the commonly accepted metrics for fine particulate matter pollution, particle mass PM10 and PM2.5, and particle number concentration.
For this, in-depth investigations of the particle formation mechanisms in the contact area between the tires and the road surface as well as the identification of the most important influencing parameters on their formation and size distribution are required in order to enable the transfer of the road test results to the test bench environment. In addition, investigations into the properties of the particles produced and the specific design of the entire aerosol measurement chain with regard to the tire emission particles are required to ensure sufficient accuracy and reproducibility. With the targeted overall solution, several advantages compared to the current state of the art can subsequently be realized by significantly improving the reproducibility and repeatability of tire emission tests, reducing the test duration and test effort, and directly quantifying tire emissions with the most suitable health- and environmentally-relevant metrics.
