Scientific background and research project:
This research project is part of the objectives of the CPER Hauts-de-France 2021-2027 program "Research and Innovation in Eco-Responsible and Autonomous Transport and Mobility" (RITMEA), led by the CNRS TTM Research Federation (FR 3733), Axis 2 "Energy Efficiency and Consumption Optimization in Mobility and Emissions," and its Work Package 3 TriboGreen "Reduction of Noise, Particulate, and VOC Emissions from Friction" (frttm.fr/ritmea). Within WP3 TriboGreen, the focus is specifically on studying ways to reduce particulate and volatile organic compound (VOC) emissions from brake wear.
Emissions of atmospheric pollutants, particles and VOCs, from the mechanical braking of vehicles are a public health concern due to their potential toxicity, which depends on their physicochemical characteristics and the quantities inhaled. In the automotive sector, the EURO7-2026 standard mandates the reduction of non-exhaust pollution and limits particulate emissions from braking. In the rail sector, high particulate concentrations in underground stations pose a significant challenge.
The use, composition and properties of friction materials in contact, along with their respective mechanical, thermal, and physicochemical (oxidation) properties, are factors that can influence the quantity and nature of braking emissions. Reducing these emissions requires: (1) accurate measurement and characterization of particulate emissions (number, mass, size, physicochemical properties) and VOC emissions (identification, quantification), and (2) identification of the predominant source mechanisms and influencing factors (materials, usage) of emissions. This knowledge will help identify actionable strategies to reduce vehicle braking emissions.
Emissions reduction will be addressed through the lever of materials, particularly friction materials, which is a practical and easily implementable solution. The project’s innovative approach involves the ability to develop friction materials (brake pads) with known compositions, tailored to specific scientific questions. For example, it will be possible to add a tracer metal or simplify the organic matrix. While particulate emissions from braking have been extensively studied, research on VOC emissions from braking is much less common.
This mission will benefit from both the expertise of LaMcube (Centrale Lille, University of Lille, Villeneuve d’Ascq) in materials science and tribology, and the CERI EE (IMT Nord Europe, Douai) in metrology and analytical chemistry of particulate and gaseous atmospheric emissions. The project will be conducted in close collaboration between the two laboratories, located 30 km apart and easily accessible by public transport or electric service vehicles (approximately 30 minutes).
Post-doctoral assignments
The project aims to improve the environmental performance of mechanical vehicle braking by studying the relationship between tribological processes and atmospheric emissions (particles and VOCs) from real or controlled-formulation materials. To achieve this, the project requires the recruitment of a post-doctoral researcher, ideally with expertise in materials physico-chemistry, tribology, and analytical physico-chemistry of atmospheric pollutants.
Initially, the research engineer will focus on expanding the range of measured VOCs to include PAHs (Polycyclic Aromatic Hydrocarbons) through sampling on suitable adsorption cartridges followed by TD-GC-FID/MS analysis.
In the second phase, two controlled-formulation composite material will be developed and physico-chemically characterized (chemical composition, thermal decomposition...). Controlled braking tests will then be conducted to study the link between tribological source processes, their influencing factors (material, usage), and atmospheric emissions.
Technical and scientific support will be provided for all these tasks.
By the end of the project, the results should enable at least one publication and one communication on the source mechanisms and factors influencing particulate and VOC emissions from braking.
