In New York City, congestion pricing leads to marked drop in pollution
e360.yale.edu452 points by Brajeshwar a day ago
452 points by Brajeshwar a day ago
> Particulates issued from tailpipes can aggravate asthma and heart disease and increase the risk of lung cancer and heart attack. Globally, they are a leading risk factor for premature death.
Minor nitpick, but tailpipes aren't the primary source of emissions. The study is about PM2.5[0]. which will chiefly be tires and brake pads. Modern gasoline engines are relatively clean, outside of CO2, though diesel engines spit out a bunch of bad stuff.
It's true that brake dust is the primary PM2.5 emission from vehicles in an urban environment. However the PM2.5 component from tail pipes are still very significant, higher than the contribution from tires.
The order is:
1. brake dust 2. road dust 3. engine emissions 4. tire dust
https://www.sciencedirect.com/science/article/abs/pii/S00456...
https://electrek.co/2025/05/27/another-way-electric-cars-cle...
and would it be true to say that regenerative braking on electric cars reduces significantly this dust?
Absolutely. Nearly eliminates. Even non-plugin hybrids have greatly reduced.
There was a "study" going around claiming otherwise, which sampled air captured by passing vehicles with a trash bag on a busy road, claiming EVs did not reduce brake dust, but even my brief summary here makes it extremely obvious how flawed this "measurement" is.
For those of us unclear why collecting air from passing cars to measure particulates is obviously flawed, could you elaborate?
EVs unfortunately do increase tire particulate, as well. Fairly significantly. It's not obvious to me that the decrease in brake dust isn't made up by the increase in tire dust.
The removal of the tailpipe emissions is really where EVs shine from a pollution standpoint. If you turn on your car in your garage, you don't die anymore.
EV brake pads don't hardly wear down, so they obviously can't have nearly the same amount of brake dust, yet the "study" showed they did. I'm guessing there's brake dust on the ground being kicked up.
> EVs unfortunately do increase tire particulate, Fairly significantly
In the USA, mass of EV is not significantly different than the alternative choice. EVs do not have increased tire particulate. If in Europe extremely lightweight tiny cars are actually a likely substitution for nicer, heavier EVs, then it seems reasonable that tire wear will increase proportionally. There's a lot riding on that "if" though.
It's not just the fact that EVs are heavier than the non-EV version of the same car, it's also that the regenerative braking means that the tires are dissapating energy that otherwise would have gone to the brake pads or to air resistance. Tires wear way faster on an EV, their lifespan in miles is generally much shorter.
> it's also that the regenerative braking means that the tires are dissapating energy that otherwise would have gone to the brake pads or to air resistance
This does not seem correct...
- Air resistance slows the car without putting anything extra through the tyres (the friction is between car and air rather than between tyre and road)
- Regenerative braking channels energy into the battery, and also heat, that would otherwise be dissipated by heating and ablating the brake pads and discs, but regardless or whether it's brakes or the the motor acting as a dynamo that puts resistance on the rolling of the wheels, for a given amount of braking you will have the same forces between the tyres and the road and the same tyre wear.
So I'd expect it's only any additional weight that contributes to increase tyre particulates from electric care. Perhaps a tiny contribution from lower air resistance (on average at least) for electric cars, as there's often quite an effort to reduce the drag coefficient for range reasons, but I wouldn't expect this to be substantial as air resistance is not huge part of braking.
Regenerative braking needs something to act against in order to slow the car down. Whether the thing on the car side is an electric motor generating voltage or a brake caliper generating heat, the effect of both is to create resistance to the axle turning. This slows the car via tire-road friction.
EVs tend to use regenerative braking, thus applying road-tire friction, much more often than an ICE vehicle uses brakes. In an EV if you are going tobfast and let off the accelerator, the regen braking slows you. With tires. In an ICE car, you will coast along and slowly slow down, mainly due to air resistance, unless you actively press the brake.
If regen braking only happened when then EV driver pushes the brake pedal with their foot, your expectations would be correct and weight would be the only differentiator. But the single pedal driving design decision means the tires wear more.