Automotive braking is a source of highly charged aerosol particles

Although the last several decades have seen a dramatic reduction in emissions from vehicular exhaust, nonexhaust emissions (e.g., brake and tire wear) represent an increasingly significant class of traffic-related particulate pollution. Aerosol particles emitted from the wear of automotive brake pads contribute roughly half of the particle mass attributed to nonexhaust sources, while their relative contribution to urban air pollution overall will almost certainly grow coinciding with vehicle fleet electrification and the transition to alternative fuels. To better understand the implications of this growing prominence, a more thorough understanding of the physicochemical properties of brake wear particles (BWPs) is needed. Here, we investigate the electrical properties of BWPs as emitted from ceramic and semi-metallic brake pads. We show that up to 80% of BWPs emitted are electrically charged and that this fraction is strongly dependent on the specific brake pad material used. A dependence of the number of charges per particle on charge polarity and particle size is also demonstrated. We find that brake wear produces both positive and negative charged particles that can hold in excess of 30 elementary charges and show evidence that more negative charges are produced than positive. Our results will provide insights into the currently limited understanding of BWPs and their charging mechanisms, which potentially have significant implications on their atmospheric lifetimes and thus their relevance to climate and air quality. In addition, our study will inform future efforts to remove BWP emissions before entering the atmosphere by taking advantage of their electric charge.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:121

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 121(2024), 13 vom: 26. März, Seite e2313897121

Sprache:

Englisch

Beteiligte Personen:

Thomas, Adam E [VerfasserIn]
Bauer, Paulus S [VerfasserIn]
Dam, Michelia [VerfasserIn]
Perraud, Véronique [VerfasserIn]
Wingen, Lisa M [VerfasserIn]
Smith, James N [VerfasserIn]

Links:

Volltext

Themen:

Brake wear particles
Journal Article
Nonexhaust emissions
Particle charge state

Anmerkungen:

Date Revised 05.04.2024

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1073/pnas.2313897121

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369566068