Charged Particles from Braking: A Hidden Air Pollution Threat
A new study from the University of California, Irvine (UCI) reveals a surprising detail about air pollution from vehicles: most of the particles released during braking are electrically charged. This discovery could pave the way for new strategies to clean up the air, especially as electric vehicles become more common.
Research led by doctoral candidate Adam Thomas and Professor Jim Smith found that up to 80% of the tiny particles released when a car brakes carry an electric charge. This is significant because charged particles can be more easily removed from the air.
“If they are charged, they can be removed easily from the air before they have a chance to have an impact at all on health,” said Smith. “All you would need to do is to collect them with an electrostatic precipitator – a device that exposes the charged particles to an electric field and efficiently sweeps them away.”
The study used a special setup with a spinning brake rotor and caliper to simulate braking and measure the emitted particles. The team was surprised that this phenomenon hadn’t been studied extensively before, given the prevalence of cars in modern society. Smith noted that the potential health impacts of these particles are largely unknown but may include oxidative stress.
This research is part of a broader effort at UCI to investigate non-tailpipe emissions, which are especially relevant in areas with heavy traffic. Researchers are also looking at how brake pad materials affect the charge and amount of particles released.
As electric vehicles replace gasoline cars, the need to address brake emissions becomes even more crucial. While EVs have zero tailpipe emissions, they still produce brake particles. This study highlights the importance of considering all sources of vehicle-related air pollution.
The UCI team is also focused on environmental justice. Low-income communities often experience higher traffic levels, which means they are disproportionately exposed to brake emissions. This is an important aspect of the problem.
The team is working with local community organizations to spread the word about their findings and potential solutions.
Funding for the study comes from a settlement with Volkswagen, as part of a 2016 agreement related to air pollution. The UCI study offers a pathway towards cleaner air by addressing an often-overlooked source of pollution.
The research underscores the role of universities in discovering and addressing emerging environmental issues.
