Journal Article

Laboratory and on-road testing for brake wear particle emissions: a review

Feo, Maria Luisa, Tratzi, Patrizio, Paolini, Valerio, Battistelli, Francesca, Torre, Marco, Tomassetti, Laura, Petracchini, Francesco, Guerriero, Ettore

2023

Overview

Brake wear emission is a significant contributor to vehicle-related particulate matter, especially in areas with high traffic density and braking frequency. Only recently, non-exhaust emissions from car brake wear have been regulated under Euro 7 regulation, which introduces emission limits for both brake and tires. It also introduces a standard brake particle assessment procedure which includes sampling procedure and measurement techniques defined in the Global Technical Regulation on brakes from light-duty vehicles up to 3.5 t. Over the years, various experimental setups have been tried leading to non-comparable results. The brake wear particle emissions, expressed as emission factors, are mostly estimated as particle mass or particle number and described using different units (e.g., mg/stop brake, mg/km brake; particle number/cm 3 ) making the comparison between studies very difficult. The aim of the present literature review is to present the state-of-the-art of different experimental methods tuned for assessing brake wear emissions, including electric vehicles. The experiments are carried in close, semi-closed, and open systems, and depending on the experimental design, different sampling methods are applied to reduce particle transport loss and guarantee the efficiency of the particle sampling. Driving condition (e.g., speed and applied pressure), formulation of brake materials, and friction temperature have been found to strongly affect the emission characteristics of brake particles, and this needs to be considered when designing study procedures. The findings reported in this review can be beneficial to policy makers and researchers.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Air Pollutants - analysis / Aquatic Pollution / Atmospheric Protection/Air Quality Control/Air Pollution / Automobiles / Brake forming / Brake presses / Design of experiments / Driving ability / Driving conditions / Earth and Environmental Science / Ecotoxicology / Electric vehicles / Emission analysis / Emissions / Emissions control / Environment / Environmental Chemistry / Environmental Health / Environmental Monitoring - methods / Exhaust emissions / experimental design / Experimental methods / friction / issues and policy / Laboratories / Literature reviews / Measurement techniques / Open systems / Particle mass / Particle Size / Particulate emissions / Particulate matter / Particulate Matter - analysis / particulates / Research methodology / Review Article / Sampling / Sampling methods / temperature / Tires / traffic / Traffic volume / Vehicle Emissions - analysis / Waste Water Technology / Water Management / Water Pollution Control / Wear particles