More electric vehicles change city air in ways that are easy to miss. A new analysis comparing London, Milan, and Barcelona reports that battery electric cars cut brake dust by about 83 percent thanks to regenerative braking, while eliminating tailpipe emissions altogether.

That is only half the story. Electric cars also tend to be heavier, so they can increase tiny particles from tires even as brake dust decreases.

Benedetto Giechaskiel, PhD, European Commission Joint Research Centre (JRC), has led peer-reviewed work on how pads, discs, filters, and regenerative braking shape these non-exhaust particles. His measurements help translate lab findings into what commuters actually breathe.

What the new study found

As tailpipes clean up, non-exhaust emissions from brakes, tires, and road wear now make up a larger slice of urban particulate pollution, especially where traffic stops and starts.

A major OECD report details how braking patterns, vehicle weight, and road surfaces push these particles into the air and onto streets.

The London case stands out because frequent junctions and lights magnify braking, and that is where regenerative systems shine.

Electric vehicle drivetrains recover speed as electricity, so the friction brakes work less, slashing the dust that otherwise becomes airborne near crosswalks and bus stops.

Brake dust is different from tire wear

Brake dust tends to produce more airborne fine particles at the curb, which is what people inhale.

By contrast, only a small fraction of tire wear becomes airborne PM10, with one comprehensive review estimating about one percent. Most tire fragments settle on roadsides or wash into drains.

That difference matters for exposure during rush hour. Fewer friction brake events in electric cars therefore mean fewer of the particles most likely to get into lungs, even though heavier curb weights still nudge tire wear upward.

Why public health researchers care

“Clean air is fundamental to health,” wrote the AQI guideline authors for the World Health Organization in 2021.

Particulate matter is not one thing but a mix of sizes and chemistries, and the smallest particles, PM2.5, are most closely tied to asthma attacks, heart strain, and early death. 

Brake dust also carries metals like copper and iron, while tires add rubbery microplastics and sulfur-bearing compounds. Scientists are mapping how these ingredients behave once they settle into soil and water, and how much re-enters the air as traffic stirs the surface.

How regenerative braking changes the math

Regenerative braking is simple in concept. When a driver lifts off the accelerator, the motor runs as a generator, slowing the car without pushing pads onto discs and sending a surge of electricity back to the battery.

That shift away from friction braking is why electric vehicle fleets can show sharp declines in brake emissions on busy city streets.

It also explains why data from multiple cities point in the same direction even though vehicle mixes and speeds differ.

Rules are catching up

For the first time, the European Union’s limits regulate brake particle emissions, beginning with light duty vehicles type approved from late 2026, with tire wear requirements to follow for passenger car tires from 2028 and later for other classes.

That step will not fix legacy fleets overnight, but it sets a clear target for manufacturers and city agencies planning low emission zones.

“The electrification of vehicles can reduce the emissions by 60 to 80 percent due to regenerative braking,” said Benedetto Giechaskiel, European Commission Joint Research Centre. Peer-reviewed findings back up the engineering logic on the road. 

What this means for city air

More electric vehicles mean fewer fumes at street level and far less dust from brakes where people walk, wait, and bike.

Tires still shed material, but only a small slice becomes fine airborne dust, and smarter street cleaning and runoff treatment can keep more of the heavier debris out of the air.

That adds up to practical choices for agencies and drivers. Smoother traffic flow, modest speed limits, and gentler driving styles trim brake and tire wear for every vehicle, while electrification removes tailpipe pollution and curbs the worst non-exhaust particles where they most affect health.

The study is published in Atmosphere.

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