##Significance

The coming decades promise a transition from internal combustion engines to electric, and with it a greater relative contribution of nonexhaust sources to urban air pollution. A chief concern is particles generated from automotive brake wear, which have adverse impacts on health and the environment. Our study reports on the electrical properties of brake wear particles, demonstrating that up to 80% of these particles are electrically charged. We show evidence for surprisingly high numbers of elementary charges per particle and report on this number’s dependence on particle size and charge polarity. These findings suggest that control strategies that exploit the unique electrical properties of brake wear particles can be highly effective in mitigating this key emerging source of pollution.

##Abstract

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.

https://www.sciencedaily.com/releases/2024/03/240312133918.htm

  • Pretzilla@lemmy.world
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    4 months ago

    BEV’s have minimal brake use - it’s all about the regen.

    Tire wear particles are now the biggest contributor.

    Not sure I’m understanding the charged particles issue. Or why they focus on BWP’s.

    • skysurfer@lemmy.world
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      4 months ago

      Looks like they are thinking charged particles would be easier to remove with an oppositely charged scrubber and the focus on BWP is due to the unknown health impact of the various brake materials.

    • AA5B@lemmy.world
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      4 months ago

      Yeah, it doesn’t make sense to have a blurb about brake particles becoming more common with electric vehicles. They never mentioned regen, and everyone else expects brake use to go way down with EVs.

      I do like that there may be a way to capture the particles, but I don’t see how this is an EV article

      • Everythingispenguins@lemmy.world
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        4 months ago

        I think that was just a poorly worded sentence. I think they were trying to say that tailpipe emissions are not the only emissions from a car and when you cut tailpipe emissions to zero. Then everything else becomes a much higher percentage of total emissions for the vehicle. They just did a bad job saying that in the abstract. Data scientists are usually not great writers and they are trained to write in a very specific way that is not very easy read by lay people.

    • lefaucet
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      4 months ago

      They’re celebrating the discovery that the charge of these particles means we may be able to capture them before they escape into the surrounding environment.

      Its a good thing! A potenrial way to solve a problem people have ignored because gas/diesel toxic particles way overshadowed brake dust.

    • Num10ck@lemmy.world
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      4 months ago

      The manufacturer that announced car tires made out of mushrooms is Michelin. They developed a concept tire called the “Visionary Concept,” which features a tread made from biodegradable materials, including rubber from dandelions and a compound made from orange zest, as well as a structure made from biodegradable materials, such as wood, paper, and bamboo.