Brake & Tire Wear Emissions
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Principal Investigator/Author: Sandeep Kishan
Contractor: Eastern Research Group, Inc.
Contract Number: 17RD016
Project Status: Completed
Relevant CARB Programs: Mobile Source Emissions Research Program
Topic Areas: Research, Zero-Emission Transportation, On-Road Heavy-Duty Vehicles, Air Pollution, Air Quality Monitoring.
Research Summary:
California's vehicle emission inventory, EMFAC, helps CARB keep track of important sources of pollution and is a critical tool in mitigating air quality issues on both regional and local levels. Updates to the inventory are necessary to continue meeting air quality goals and to understand how regulatory measures may impact air quality. EMFAC predicts that non-exhaust sources, such as brake and tire-wear, are the main source of primary PM from on-road vehicles. In order to ensure that the model is updated and has detailed information on this source as a function of vehicle type, vehicle age, and vehicle driving behavior, CARB awarded a contract to Eastern Research Group, Inc. (ERG) and Link Engineering (LINK) to measure and characterize PM emissions from a variety of brake components and under various operating conditions. ERG and LINK used an enclosed brake dynamometer connected to a constant volume sampler (CVS) with carefully controlled climate conditions to measure brake PM emissions using state-of-the-art measurement techniques. The investigators have provided a detailed report summarizing their findings. They found that PM emissions were sensitive to braking materials, braking force, and simulated vehicle weight. The investigators also simulated regenerative braking, a typical feature of advanced clean cars, and found that this technology led to lower overall PM emissions. The test results will be used to create new emission factors for the EMFAC model. Given that brake-wear is currently estimated to be the largest source of primary PM from on-road vehicles, updates to the model that include current materials and advanced technologies will help CARB better assess how these emissions will impact air quality on a regional level, but more importantly on a local scale, particularly for populations living near major roadways.
Keywords: mobile source emissions, non-exhaust, brake, tires
Final Report: Please email research@arb.ca.gov to request the Final Report generated by this research contract.