Non-Exhaust PM Emissions from Heavy-Duty Vehicles

Abstract

The important technological improvements have been made for reducing particulate matter (PM) emissions from exhaust sources, but no actions are currently in place to reduce the non-exhaust part of emissions such as those from brake wear, road wear, tyre wear and road dust resuspension. In the future these emissions will become increasingly important in relative terms. However, as exhaust emissions are set to steadily decline, in 2030, total non-exhaust emissions will be an estimated 1.6 times greater than total exhaust emissions. Non-exhaust emissions are more difficult to quantify than exhaust emissions owing to the strong influence of not only the type of vehicle and traffic conditions, but also the material properties and meteorological factors. Most studies indicate that emission factors for PM from brake wear are significantly larger from heavy-duty vehicles (HDVs) than from light-duty vehicles (LDVs). This would be due to the larger number or size of brakes on heavy-duty vehicles and the fact that the larger vehicle weight releases more kinetic energy in the process of slowing the vehicle down. HDVs contributed five to ten times more resuspended road dust than LDVs. One of the objectives of this paper is to overcome significant gaps still exist in our understanding of the participation of HDVs in total non-exhaust emissions.