Airborne wear particles from automotive brake systems in urban and rural areas

Abstract

Non-exhaust vehicle emissions are currently thought to be tyre wear, brake wear, clutch wear, road surface wear, corrosion of other vehicle components, corrosion of street furniture and crash barriers, and the resuspension of road dust. Among non-exhaust sources, brake wear can be a significant particulate matter (PM) contributor, particularly within areas with high traffic density and braking frequency. Regulations for brake pad performance are influenced by many bodies across the world, including the Particle Measurement Programme by the United Nations Economic Commission for Europe (UNECEPMP). In order to continuously improve their products and ensure regulatory compliance, brake pad manufacturers conduct brake performance tests and they can be carried out on vehicles and on dynamometers. The main topic of this paper regards the potential impact of the emitted PM on the human health, depending on the mechanisms of formation and toxicity of the particles. On-going European projects dealing with this important problem will also be discussed in the paper.