Thesis title: Analysis of brake system emissions and evaluation of possible mitigation strategies
This doctoral thesis investigates brake wear emissions through a combination of laboratory tests and real-world measurements. Various experimental methods, including pin-on-disc tests, dynamometer tests, and on-road measurements, were employed to assess the impact of factors such as friction material, test cycles, and friction temperature on particulate matter (PM) emissions. While laboratory tests provide controlled conditions for evaluating brake wear emissions, real-world urban environments introduce variables that significantly affect air quality outcomes. The LIFE "RE-BREATH" project in Bergamo offered a unique opportunity to analyze brake wear emissions from public transport (TPL), specifically buses, under actual operating conditions. The demonstration activities focused on non-exhaust emissions and PM10 concentrations at bus stops, critical exposure points for passengers and pedestrians. The findings indicate that innovative brake systems can significantly reduce particulate emissions at these hotspots, with a new brake formulation achieving a 34.5% reduction in PM10 emissions compared to traditional materials. Additionally, the optimized Brembo "RE-BREATH" material demonstrated reduced wear on both brake pads and discs, enhancing durability and decreasing maintenance requirements. High-resolution atmospheric modeling using ADMS-Roads further validated the role of brake wear emissions in urban air pollution. Simulations in Bergamo and Bratislava confirmed that non-exhaust emissions contribute up to 30% of local PM10 levels, with bus brake wear alone accounting for up to 15% in certain hotspots. Reduction scenarios showed a direct correlation between lower brake wear emissions and decreased PM10 concentrations, reinforcing the potential of targeted interventions in urban air quality management. This doctoral research highlights the importance of identifying specific brake wear indicators for more precise source apportionment and regulatory measures. The results underscore the need for a multifaceted approach to air quality improvement, integrating technological advancements in braking systems with urban mobility strategies and regulatory frameworks. The demonstration activities in Bergamo provide valuable insights for policymakers and industry stakeholders, emphasizing the tangible benefits of innovative brake technologies in reducing air pollution and improving public health.