California Air Resources Board

Principal Investigator/Authors: Sandeep Kishan

Contractor: Eastern Research Group

Sub-contractor: LINK Engineering

Contract Number: 24RD006

Project Status: Active

Relevant CARB Programs: Mobile Source Emissions Inventory

Topic Areas: off-road equipment, Non-Exhaust Emissions

Research Summary:

California’s regulations on tailpipe emissions have significantly reduced air pollution from vehicle exhaust. The remaining emissions from mobile sources are non-exhaust emissions, including from vehicle brake-wear. Although these emissions have always been present, they now receive attention because exhaust emissions have been reduced to lower concentrations. As a relatively new area of study, non-exhaust emissions are not well characterized, especially for off-road vehicles. The current off-road emissions inventory does not include brake-wear emissions, which may contain air toxics and potentially cause adverse health effects.

The objective of this project is to characterize emissions of particulate matter and gaseous air pollutants from off-road vehicles, including agricultural equipment and construction equipment. A laboratory brake-wear simulator will be used to generate emissions from braking systems used in off-road vehicles. The simulator will be operated to closely represent real-world vehicle activity by incorporating data collected from real off-road equipment into the experimental design of the braking cycles. Emissions will be measured using a suite of analytical instruments. Numerical and chemical analysis will be performed to determine emission factors, which will be used to inform our mobile source emissions inventory. Exposure analysis will be conducted to help assess the impacts of these emissions on disadvantaged communities near agricultural areas and construction zones.

Keywords: Non-exhaust emissions, brake-wear emissions, off-road equipment, agricultural vehicles, construction vehicles, tractors, mobile source emissions inventory, brake dynamometer, mobile source emissions, volatile organic compounds (VOCs), particulate matter (PM)