Roadside Characterization of Heavy-Duty Vehicle Non-Exhaust Particle Emissions Using Plume-Based Emission Analysis Methods

As internal-combustion engines are increasingly replaced by electric vehicles, non-exhaust emissions (tire, brake, and road wear) will play a much larger role in urban air pollution. Already, these emissions make up a significant portion of particulate matter in urban settings and do not fall under existing regulations, despite being associated with negative health outcomes.

Emission factors reported in previous studies on non-exhaust emission sources show limited agreement in particle number and mass likely due to variability in driving behaviour, vehicle characteristics, and methodological differences. In addition, non-exhaust emissions from heavy-duty vehicles have not been substantially explored in the literature, despite their potential to be large emitters.

This roadside emission study targets non-exhaust emissions on the causeway to Global Container Terminals Deltaport in Vancouver, Canada where there is a significant presence of heavy-duty vehicles and reduced regional emission sources. Sampling was conducted on seven days throughout October and November 2025. Sample air was taken at the road surface and 1.5 m from the road edge. Using real-time monitoring instruments, including a Dekati electrical low pressure impactor (ELPI+), and a CO2 gas analyzer (LI-850), fuel-based emission factors for non-exhaust emissions are explored as a potential alternative to existing reporting methods. A second and independent emissions monitoring setup was used in parallel and focused on exhaust emissions which offers opportunities for isolating the non-exhaust component of vehicle emissions.

The estimated mean vehicle plume-based particle number and mass emission factors, which include both exhaust and non-exhaust emissions, are 5.85×10^16 particles per kg of fuel and 9.58×10^4 mg per kg of fuel, respectively. Emission factor distributions for both particle number and mass span four orders of magnitude, indicating the presence of high-emitting vehicles within the fleet.