Non-exhaust Emissions Emerge as Primary Source of Particulate Pollution

Air pollution from microparticles (PM) remains one of the most severe environmental health threats in Europe. In 2022, over 96% of the population was exposed to PM 2.5 concentrations (particles with a diameter of 2.5 microns or less) exceeding the limits set by the World Health Organization.

A new study commissioned by EIT Urban Mobility, an initiative of the European Institute of Innovation and Technology (EIT), along with Transport for London (TfL) and the Greater London Authority (GLA), reveals that non-exhaust emissions (NEE - particles released from brake, tyre, and road surface wear) have become the primary source of land-based particulate pollution from transport.

The findings were presented at the Annual Summit of the International Transport Forum (ITF) in Leipzig, in a session led by Yoann Le Petit, Director of Thought Leadership at EIT Urban Mobility, alongside representatives from TfL and the GLA.

Nationally, the study urges governments to implement Euro 7 standards, promote innovation in low-wear materials, and support the renewal of existing vehicle fleets. According to Le Petit, it is essential for European institutions to establish harmonised measurement methods.

With traditional exhaust emissions decreasing due to electrification and new regulations, attention is shifting towards NEE. In London, Milan, and Barcelona, these emissions account for between 68% and 88% of PM 10 from road transport and up to 78% of PM 2.5. Besides affecting air quality, NEE particles pollute water and soil, raising concerns about long-term ecological damage and microplastic accumulation.

Brake wear is currently the largest source of NEE in urban areas, with over 40% of resulting particles remaining airborne. Tyre wear is also significant, although most particles settle on asphalt or disperse into surrounding ecosystems. Urban driving, with frequent stops and starts, exacerbates both forms of pollution. Future Euro 7 standards will, for the first time, impose restrictions on emissions from brake and tyre wear—from 2026 to 2028, respectively—though for tyres, it will only apply to new vehicles.

The EIT Urban Mobility study concludes that early adoption of anti-wear components across all fleets could yield significant benefits sooner than expected. However, it warns that any transition must be accompanied by a robust assessment of material toxicity to avoid unforeseen consequences. Beyond technical solutions, the gradual abandonment of private car use emerges as the most effective strategy. Models analysed indicate that replacing car journeys with public transport, walking, or cycling reduces particulate emissions up to five times more than electrification alone. The impact is even greater when both measures are combined.

In a cost-benefit simulation for London, implementing anti-wear brakes and tyres emerges as the most economically effective measure, with an estimated net social benefit of €235 million by 2050. Nevertheless, these benefits could significantly increase with specific changes in travel patterns and vehicle use.

The study proposes a multi-level approach to addressing NEE. It calls on local authorities to consider NEE as a significant source of pollution and act accordingly. This means supporting vehicle electrification, expanding low-emission zones, reducing speed limits to decrease braking, promoting vehicle lightening, and ensuring road maintenance to minimise surface wear. Investments in public transport, walking, and cycling infrastructure should form the backbone of initiatives to reduce car dependency.