"Despite the slightly higher levels of tire wear from EVs, brake dust was found to be more unhealthy, as brake dust is much more likely to become airborne (>40%) than tire wear is (1-5%). So EVs create a lot less of the worse thing, and a little more of the less-bad thing."
I recently bought an EV and love it. I barely ever touch the brakes and the wheels stay clean, unlike my old BMW where the front wheels turned gray from brake dust very quickly.
Some comments here are looking for a 100% perfect solution, which doesn't exist. Transportation is polluting. Sorry but even public transportation is polluting, even if it is more efficient when its above a certain utilization. Where I live, some buses are EV and it is a joy to ride them compared to diesel ones.
With an EV there is less local pollution, less noise pollution, more dynamic response when needed and no need for wasteful oil "changes" where the old, dirty, useless oil doesn't just magically disappear.
There is an additive called 6PPD added to tires to prevent them from degrading in the atmosphere, and it has been found that when this thing reacts with ozone in the air it forms another compound 6PPD-quinone which is highly toxic to some fishes. Weirdly enough it's highly toxic to some species of salmon but not to other salmon species.
Presumably there's work ongoing to find an less damaging replacement, but I haven't heard of any.
It's not you, it's definitely me. I cannot tell if there is irony or a 'straight-faced' comment that you wrote.
Either way, like always, time will tell. We (humans) almost never 'get it right the first time'. And perhaps EVs have been around for quite a while now, it's still 'a while'. So I wouldn't be surprised if the lobby for "7PPD" (or whatever replacement) convinces us that "7PDD" is the best and even makes fish taste better, only to find out that it causes terminal cancer (see smoking, sugar, etc.)
So putting this aside, the elephant in the room is still the weight of the EVs, tire wear is one thing but the roads are also being worn at a much faster rate due to the weight of the cars. When EVs do have to brake and regenerative is not enough it needs to stop more inertia due to this high weight.
ICE cars already do that in a way, as they suck a significant amount of air through their intake filters (CADR = displacement x RPM).
Audi's filter was supposed to have been more fine-grained to catch brake dust and tire particles, but sufficient legislation never materialized, so the project was shelved.
This Audi proposal is somewhat similar in my mind. They want to profit from both parts, providing both the problem and the solution. I'm not against it per se.
You've reminded me that I was taught French early enough to instinctively follow the rhythm of the language, but today that alone won't suffice if the vocabulary isn't there.
I've known Louis de Funès from Les Gendarmes and such classics as La Soupe aux choux or L'aile ou la cuisse.
I didn't know the movie you linked, but now I'm thinking I'll pick up French again - if only to hear the whole body if his work in its original language.
The figures are sufficient, but only when the blowers are at full throttle. A room air purifier does around 300m3/h, while the blowers eat through around 150m3/h at max speed. Problem is that hardly anyone uses them like that, considering the noise.
Meanwhile a car with a 1.5l engine turning at an average of 1500RPM will suck through 135m3/h.
There's no data available for Audi's system, but at this size they could easily go way beyond 300m3/h.
> It turns out that BEVs (battery electric vehicles) reduce the amount of brake dust by 83%, according to a new analysis by EIT Urban Mobility (a body of the European Union) and Transport for London. The study looked primarily at London, Milan and Barcelona.
> The primary reason for this is the use of regenerative braking, meaning that electric vehicles can slow down without rubbing friction brakes. Other vehicles that use regenerative braking reduced brake emissions too, with Hybrids reducing them by 10-48%, and PHEVs by 66%.
Technically not cleaning the air as the title says, but still a major improvement.
Some diesel engines can clean the air, but only if the air coming in is very polluted. They'll catch and burn particulates, and they'll chemically scrub NOx. This only applies if the air outside is very polluted, though
Brake dust is such nasty stuff, yet we place schools and homes right next to the rivers of pollution that we call highways. I'm hopeful that we will legalize the building of less car-dependent housing, but until then at least EVs will help.
Yep. I’m finally in a place to bike to work and elsewhere and it’s remarkable how much I can get done without a car. But the infrastructure sucks and there’s so much room for improvement.
I do agree, but I'd like to point out that EVs aren't necessarily car-shaped. E-scooters and e-bikes can do wonders in transporting people without so many of the issues that driving produces (e.g. congestion, tyre pollution, collisions etc).
I was living on the 4th floor next to a main road once. I could wipe a thick layer of gray dust from my balcony furniture eevery two days. This surprised me initially, since it was high up and a big garden separated the road and the house.
The worst thing was the noise. When I lived there I tuned it out, but when I slept for the first night in my new flat it felt like someone lifted a huge rock from my chest.
Cars in cities are a really thing to tolerate from the standpoint of people who bear the cost of them being there, EVs help reducing two of the main issues with cars. Issues like space use remain (housing prices skyrocket while there is a ton of empty space used for storing cars while nobody drives). Who knows, maybe EVs can solve this one too one day.
Anybody who ever driven an EV, would have told that the initial scare about brake dust was pure nonsense.
EVs barely use frictional brakes, with regen performing most of the braking action. Frictional brakes only really come into play to slow down from around ~5 mph to a complete stop.
And even that can be eliminated by essentially running the motor backwards, at low torque. This mode of braking is sometimes used on train engines as an emergency braking method.
How does this generally work wrt brakes needing to be used occasionally to not rust shut? Even with an ICE car if you don't drive a lot, and drive in a fuel efficient way (e.g. coasting towards red lights) this can be an issue resulting in an expensive surprise when you need to replace disks long before they are worn out.
Some EVs (Teslas are ones I know of) have software that occasionally lightly applies the brakes to keep them clean.
Also, on EVs with LFP batteries the brakes do get used a bit more, because a full and/or cold pack usually can only take very limited power from regenerative braking. Depending on the implementation in the vehicle, brakes are either applied automatically to still allow for one-pedal-driving (aka. "brake blending", making the difference unnoticeable to the driver), or throttle-pedal regen is simply capped and the driver has to use the brake pedal when they notice that regen power is not sufficient.
Works for modern trains, too. I was watching one of the new electric CALTRAIN multiple units pull into a station. The motors did all the braking except for the last few feet of stopping. The friction brakes normally go on below 5 MPH, and are rather noisy for disk brakes. Emergency braking is friction brakes only.
The brake dust from low-noise train brakes smells so incredibly nasty (burning ABS, pretty much) but the operators and OEMs claim it’s <<safe>>. Bonus points for the Bombardier bi-level coaches, where the AC air intake is right above the wheelsets and takes a healthy gulp of that brake dust and smell and distributes it to the passengers inside (because the smell is just as pungent inside as outside a few seconds after coming to a stop I doubt the filters, if any, are doing much). Frankly I’d not commute with it.
Filters catch particulates, but not gases. Heated ABS releases chemicals like 1,3-Butadiene, a small molecule (4 carbons), gaseous at room temperature, and mildly gasoline-smelling. It's bad for you in high concentrations.
Readit News
"Despite the slightly higher levels of tire wear from EVs, brake dust was found to be more unhealthy, as brake dust is much more likely to become airborne (>40%) than tire wear is (1-5%). So EVs create a lot less of the worse thing, and a little more of the less-bad thing."
Some comments here are looking for a 100% perfect solution, which doesn't exist. Transportation is polluting. Sorry but even public transportation is polluting, even if it is more efficient when its above a certain utilization. Where I live, some buses are EV and it is a joy to ride them compared to diesel ones.
With an EV there is less local pollution, less noise pollution, more dynamic response when needed and no need for wasteful oil "changes" where the old, dirty, useless oil doesn't just magically disappear.
Presumably there's work ongoing to find an less damaging replacement, but I haven't heard of any.
https://en.wikipedia.org/wiki/6PPD
The work is underway to standardize on a replacement. This time with even more tests.
Deleted Comment
Either way, like always, time will tell. We (humans) almost never 'get it right the first time'. And perhaps EVs have been around for quite a while now, it's still 'a while'. So I wouldn't be surprised if the lobby for "7PPD" (or whatever replacement) convinces us that "7PDD" is the best and even makes fish taste better, only to find out that it causes terminal cancer (see smoking, sugar, etc.)
https://ecology.wa.gov/blog/january-2023/saving-washington-s...
The elephant in the room for road wear are trucks [1]. Cars are almost negligible.
[1] https://en.m.wikipedia.org/wiki/Fourth_power_law
Are they actually being worn out at a much faster rate because of more EVs? Do we have any data?
https://www.audi-mediacenter.com/en/press-releases/audi-urba...
ICE cars already do that in a way, as they suck a significant amount of air through their intake filters (CADR = displacement x RPM).
Audi's filter was supposed to have been more fine-grained to catch brake dust and tire particles, but sufficient legislation never materialized, so the project was shelved.
Air cleaning scene: https://youtu.be/lpmxrgrbKDc (French)
(He was responsible for first poisoning the air by burning tires, so that he could demonstrate his machine to the potential Japanese investors)
https://en.wikipedia.org/wiki/La_Zizanie_(film)
This Audi proposal is somewhat similar in my mind. They want to profit from both parts, providing both the problem and the solution. I'm not against it per se.
I've known Louis de Funès from Les Gendarmes and such classics as La Soupe aux choux or L'aile ou la cuisse.
I didn't know the movie you linked, but now I'm thinking I'll pick up French again - if only to hear the whole body if his work in its original language.
Meanwhile a car with a 1.5l engine turning at an average of 1500RPM will suck through 135m3/h.
There's no data available for Audi's system, but at this size they could easily go way beyond 300m3/h.
> The primary reason for this is the use of regenerative braking, meaning that electric vehicles can slow down without rubbing friction brakes. Other vehicles that use regenerative braking reduced brake emissions too, with Hybrids reducing them by 10-48%, and PHEVs by 66%.
Technically not cleaning the air as the title says, but still a major improvement.
Dead Comment
The worst thing was the noise. When I lived there I tuned it out, but when I slept for the first night in my new flat it felt like someone lifted a huge rock from my chest.
Cars in cities are a really thing to tolerate from the standpoint of people who bear the cost of them being there, EVs help reducing two of the main issues with cars. Issues like space use remain (housing prices skyrocket while there is a ton of empty space used for storing cars while nobody drives). Who knows, maybe EVs can solve this one too one day.
EVs barely use frictional brakes, with regen performing most of the braking action. Frictional brakes only really come into play to slow down from around ~5 mph to a complete stop.
And even that can be eliminated by essentially running the motor backwards, at low torque. This mode of braking is sometimes used on train engines as an emergency braking method.
Also, on EVs with LFP batteries the brakes do get used a bit more, because a full and/or cold pack usually can only take very limited power from regenerative braking. Depending on the implementation in the vehicle, brakes are either applied automatically to still allow for one-pedal-driving (aka. "brake blending", making the difference unnoticeable to the driver), or throttle-pedal regen is simply capped and the driver has to use the brake pedal when they notice that regen power is not sufficient.
They fixed it by having the software to apply frictional brakes once in a while to keep the rotors clean.
I have an EV with 150k miles, and the brake pads are barely worn. They are going to outlast it.
Never had any issue with rust.