Investigation on the potential generation of ultrafine particles from the tire–road interface

There has been some discussion in the literature on the generation of ultrafine particles from tire abrasion of studded and non-studded tires tested in the laboratory environment.In the present study, the potential generation of ultrafine particles from the tire road interface was investigated during real driving. An instrumented Sport Utility Vehicle equipped with summer tires was used to measure particle concentrations with high temporal resolution inside the wheel housing while driving on a regular asphalt road. Different driving conditions, i.e., straight driving, acceleration, braking, and cornering were applied. For normal driving conditions no enhanced particle number concentration in the size range 6–562 nm was found. Unusual maneuvers associated with significant tire slip resulted in measurable particle concentrations. The maximum of the size distribution was between 30 and 60 nm. An exponential increase of the particle concentration with velocity was measured directly at the disc brakes for full stop brakings. A tracer gas experiment was carried out to estimate the upper limit of the emission factor during normal straight driving.

► New experimental setup to measure ultrafine particles from the tire road interface.
► Emission factor for steady straight driving estimated with a tracer gas experiment.
► Compared to exhaust emissions (DPF-car), the emission factor is of minor importance.
► Under normal driving conditions no enhanced particle generation was found.
► Under extreme driving conditions, ultrafine particles (30–80 nm) could be measured.