UK – A new study published in Particle and Fibre Toxicology has revealed that particulate matter generated by brake wear can be more toxic to human lung cells than diesel exhaust particles. Researchers at the University of Southampton tested four common brake pad types: “low metallic, semi-metallic, non-asbestos organic (NAO), and hybrid-ceramic, exposing human lung epithelial cells to the dust they produce”. The analysis found that NAO and ceramic pads caused the strongest oxidative stress and inflammatory responses, linked to their high copper content, with concentrations up to 300 times greater than those found in diesel particles.

The study, independently carried out by Southampton University researchers, highlights the growing significance of non-exhaust emissions, which now account for the majority of particulate pollution from vehicles. For the commercial vehicle sector, this poses a fresh regulatory and operational challenge. Brake wear is particularly acute in heavy-duty vehicles, meaning operators and manufacturers alike may face pressure to mitigate health impacts through new brake materials, wider adoption of regenerative braking, or even future emissions standards targeting non-exhaust sources.