Euro 7 Emissions Regulations Set to Tackle Non-Exhaust Particulate Matter
The automotive industry is undergoing a significant shift as the focus on combustion-engine vehicles diminishes and attention turns to other factors contributing to pollution. One such factor is non-exhaust particulate matter, which includes particles emitted from tires and brakes. With Euro 7 emissions regulations set to come into force in July 2025, the industry is preparing to tackle this issue head-on.
Tyre companies have been proactive in researching and addressing the problem of tyre wear particulates. Michelin, for example, has been studying the issue for the past 20 years. In the UK, engineering consultancy Ricardo, in collaboration with Arup, published a report on how to measure these particulates, commissioned by the Department for Transport.
The European Commission is also taking action by producing a report by the end of this year to review measurement methods and the broader subject of tyre abrasion. The latest proposal suggests that emissions of PM10, which refers to particulates of 10 microns or less in diameter, will be limited to 3mg/km (3000th of a gram every kilometer or roughly 5mg per mile). To put this size into perspective, a human hair is 50-60 microns in diameter.
Regulating non-exhaust particulate matter is one thing, but measuring such tiny particles presents a challenge. However, Michelin has come up with a straightforward and innovative method using suction and a two-stage measuring system. The first stage involves drawing in air from the front of the test car to establish a background measure of ambient particulates. This measurement is then compared with samples taken directly behind a tire.
To measure the particles, each set of samples passes through a filtration system towed behind the car. This system traps particles ranging from 10 microns to six nanometers in diameter. The second stage involves separating the particles in each filter and identifying their source using a pyrolysis process. Finally, the proportion of particles by size is quantified.
According to Michelin, less than 1% of PM10 and less than 0.6% of PM2.5 (particulates of 2.5 microns or less in diameter) come directly from the tire. The particles are a combination of 50% tire rubber, 50% minerals, and other road surface materials. The total particles produced by tire wear that remain suspended in the air, known as aerosols, average at 1.3% PM10 and just 0.16% PM2.5.
In an effort to promote collaboration and further research, Michelin is sharing the design of its equipment with the rest of the tire industry. Additionally, the European Tyre & Rubber Manufacturers Association plans to conduct large-scale research starting this year in partnership with an independent third party.
As the automotive industry continues to evolve and prioritize sustainability, addressing non-exhaust particulate matter is crucial. By implementing innovative measurement techniques and collaborating across the industry, tire companies are taking proactive steps to reduce their environmental impact and comply with the upcoming Euro 7 emissions regulations.
