6 ms·

Particulate emissions have been dropping already since decades through optimizations. Electric cars certainly reduce particulate emissions a lot further, but ti

Particulate emissions have been dropping already since decades through optimizations. Electric cars certainly reduce particulate emissions a lot further, but tire and break wear has become a significant part of particulate emissions. The best really would be to keep cars out of highly populated areas and provide good public transportation and provide walkable and bicycle-safe infrastructure.

ceejayoz 4y ago
> Electric cars certainly reduce particulate emissions a lot further, but tire and break wear has become a significant part of particulate emissions. Doesn't regenerative braking reduce both tire and brake wear?
- avelis 4y ago
  Brake wear for sure.
- ihattendorf 4y ago
  Brake yes, I don't see how it would help tire wear (assuming you slow down at the same speed). Electric cars typically have higher tire wear because of the increased weight + typically higher torque/acceleration.
  - ceejayoz 4y ago
    https://www.nokiantyres.com/company/news-article/there-is-a-common-misconception-related-to-electric-cars-in-reality-tires-will-last-for-a-long-time/ https://www.nokiantyres.com/company/news-article/there-is-a-... > Tires on a modern electric car will wear down much slower than in a car with a traditional internal combustion engine. This is due to good traction control. The driver assist systems reduce slipping by utilizing the electric motor's rapid power adjustment. This system is much quicker than in ICE vehicles, where it is based on braking and limiting engine RPM, Liukkula says. I dunno if anyone's done a good scientific study on this.
    - AnthonyMouse 4y ago
      In addition to this, people are aware of the existence of regenerative braking, and that it works better when decelerating less aggressively, so they do. Which puts less wear on the tires.
    - Gordonjcp 4y ago
      Sounds like shit to me. How much time do you spend spinning your tyres and braking so hard you skid?
      - deleted 4y ago
        [deleted]
      - ceejayoz 4y ago
        You don't have to fully skid the thing to see a benefit from better control over the breaking process. From the skid marks I've seen on the highway, rare skids seem to pull off a significant amount of rubber in one incident.
      - sokoloff 4y ago
        The tires cannot generate any longitudinal acceleration with zero slippage. This slippage is what causes wear. (As a driver, though you perceive there to be zero slippage without wheelspin or sliding the tires, there is slippage between the road and tire anytime the tire is exerting a longitudinal force on roadway.)
    - smachiz 4y ago
      This was, in my experience, not true. Ask most Tesla owners as well. The heavier car + much better acceleration created more tire wear than any improvements to traction control from faster power response (though I'm not sure intrinsically why that would reduce wear - ICE cars can apply brakes to a slipping tire just as well as an EV, and instant torque doesn't feel like it would do anything positive for tire wear). Fitting lower rolling resistance tires on ICE cars would provide any of the same benefits that EVs receive.
      - 4y ago
  - rob74 4y ago
    Anecdotal evidence: I regularly manage to (unintentionally) spin the wheels in a petrol car, but I have never managed to do it in an electric car yet, despite trying out the full acceleration. So while the torque is undeniably greater, apparently the motor management control is also better, so it can deliver maximum acceleration without increased tire wear - at least in the electric cars I have been driving (mostly BMW i3).
- comte7092 4y ago
  Brakes certainly, but all motion still needs to be stopped through friction against the ground. EVs are significantly heavier for the time being, so if anything they have greater wear on tires all else equal.
  - malfist 4y ago
    Is that true though? Energy has to go somewhere, but if you store a large part of that energy into batteries, doesn't that take away from what you have to expend on friction with the road? After all, energy can't be created or destroyed. So if you're storing it in batteries, it's coming out of your forward momentum.
    - SamBam 4y ago
      Energy that would normally have been lost in heating up/destroying the brake pads instead goes into the battery, of course. But I don't see why this alone would affect the tire tread.
    - comte7092 4y ago
      You aren’t regaining 100% of the kinetic energy so a significant part has to be lost somewhere else. Realistically regenerative braking is recouping energy that would be lost as heat when the friction brakes act on the wheels. However it would not stop a vehicle on a zero friction surface, as a simple example, so no it doesn’t take away from the friction heat losses on the road.
    - deleted 4y ago
      [deleted]
    - rootusrootus 4y ago
      > Is that true though? 100%. Brakes do not stop a car, tires do. Brakes just manage the energy. Putting it back into a battery so it can be used to accelerate again is great, but it's still the tires stopping the car.
      - mlindner 4y ago
- ewgoforth 4y ago
  Brake wear yes, but the resistance to forward motion still has to be transferred via that tires.
- malfist 4y ago
  Quick google says regenerative breaking has ~65% efficiency at energy recovery, but that includes the 10-20% lost when converting stored energy back into kinetic energy. So it sounds like regenerative breaking would covert ~75%-85% of kinetic energy into stored chemical energy. I'd expect to see similar reduction in tire and brake wear as well, maybe even more it probably depends on how break dust is generated, if it has a curve where more is generated with greater breaking force applied, by dropping the force on a break pad to 15% of it's previous value we might see an even greater reduction. This is all speculation though, I am not a physicist.
  - qqtt 4y ago
    The energy efficiency of turning regenerative braking into energy isn’t really related to how regenerative braking can fully stop a vehicle without using the brake pads. Even if the regenerative braking energy efficiency were 1% - if it fully stops the car without using a brake pad that entire wear & tear (& dust) goes away.
    - vagrantJin 4y ago
      Thanks for pointing this out. Many arguments here are about regenerative braking - which does not the address the issue of tire wear.
- hn_throwaway_99 4y ago
  Absolutely. I have an EV that has an "aggressive regenerative braking" setting where pulling your foot off the accelerator slows the car considerably. In that setting I almost never touch the brake.
  - jeffbee 4y ago
    Putting your foot on the brake pedal has almost nothing to do with whether the friction brake is engaged in an EV or hybrid. A computer decides when and how much to pressurize the friction brakes.
    - hn_throwaway_99 4y ago
      That's true, but my point is that, at least in my car, taking your foot off of the accelerator does not ever engage the friction brakes, and when I drive it's nearly 100% "one pedal driving". What you're saying, that when you do press the brakes that a computer decides how much to apply regen vs friction, is true, but again, my point is that I don't touch the brakes.
    - sliken 4y ago
      Depends on the car, the Tesla default setting is not use brakes when you life the throttle or use regeneration when you hit the brake. This lets you control how you slow down, which makes it easier to be nearly 100% regenerated.
- deleted 4y ago
  [deleted]
- giardini 4y ago
  Regenerative braking will reduce brake pad wear since part of the power otherwise dissipated as braking friction between pad and disc/drum is captured by the motor/generator, converted to electrical power and stored. Tire wear should be unaffected provided the e-car has a "freewheeling" feature whereby braking is not applied unless the driver hits a brake pedal. If the e-car is set to always run in a regenerative braking mode (brake goes on if driver eases off the "gas" pedal) then the braking will actually increase tire wear.
rqtwteye 4y ago
I agree about tire and brake wear but the air in cities will be incredibly better with only electric cars.
- Gordonjcp 4y ago
  You could just run ICE-powered cars on cleaner fuels like propane. There's a reason warehouse forklifts - which drive around inside completely enclosed buildings - run on propane.
  - brianwawok 4y ago
    I’d prefer nothing out of tailpipes vs “cleaner combustion”
  - mlindner 4y ago
    > You could just run ICE-powered cars on cleaner fuels like propane. From my understanding a lot of the pollution is just from heating up the incoming air containing nitrogen. Unless you're taking your oxidizer with you rather than using the air to burn that propane, you're still going to produce toxic-to-humans nitrogen-based oxides (pollution) from exploding the gas in the presence of nitrogen. In fact depending on how you do it (for example if the combustion temperatures end up higher) you could have significant increases of such compounds versus gasoline combustion. Best to keep the combustion vehicles to antiques/collectables and make all daily drivers use electricity.
    - Gordonjcp 4y ago
      Burning propane in car engines produces carbon dioxide and water, no sulphur oxides (because there's no sulphur in the fuel, or such a tiny amount that it is negligible) and no nitrogen oxides. You can actually measure this. It burns leaner than petrol resulting in complete combustion so there's no CO or HC in the exhaust, either. Indeed, if there's enough CO and HC in the environment from other vehicles you'll actually be burning that too giving it (in a sense) negative emissions figures.
  - rqtwteye 4y ago
scythe 4y ago
It seems like everyone has become an expert on tire particulates over the last five years. You can't read a thread about EVs without hearing about it. But NOx emissions are actually more strongly correlated with many health outcomes, e.g.: https://www.mdpi.com/1660-4601/17/3/754 https://www.mdpi.com/1660-4601/17/3/754
- dahfizz 4y ago
  With particulate sensors becoming a cool new toy, I think a lot of people have the misconception that all particulate matter is the same (because that is all they can measure, so they focus on that one number). They don't stop to think whether the particles themselves are water droplets, poisonous chemicals, or something in between. I've had people tell me that campfire smoke is more deadly than cigarette smoke, because the campfire has more particles.
- legulere 4y ago
  Your study is only about asthma and bronchitis This study estimates that the disability adjusted life years lost by PM2.5 are orders of magnitude higher than from NO2: https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.1104035 https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.1104035 see figure 3 I'm fully agreeing that electric cars reduce pollution, I also ordered one myself. But they do not fully solve the pollution problem and reducing our dependency on cars is the most effective way to reduce negative effects.
jasonwatkinspdx 4y ago
About a decade ago I worked for 6 months in a temporary office near a very heavily trafficed overpass. This office didn't have AC (not exactly uncommon in the PNW) so we had the windows open during the summer. The amount of particulate that would build up on everything in just an hour was pretty dumbfounding.
electrondood 4y ago
EVs have next to zero brake wear. They do chew through tires faster due to increased torque. A lot of the particulate consists of petroleum parts, catalytic converter, etc. Components that EVs just don't have.
- jeffbee 4y ago
  Characterizing "a lot": according to the Bay Area Air Quality Management District, particulate emissions from on-road gasoline vehicles consists of 20% tailpipe emissions and 80% brake, tire, and resuspended road dust.
  - dahfizz 4y ago
    > particulate emissions I think that's kind of obvious, as most tailpipe emissions are gaseous, not particulates. What really matters, instead of blindly counting particles, is health outcomes. Nox fumes are strongly associated with negative health outcomes, even if it isn't strongly associated with a particulate count.[1] [1]https://www.mdpi.com/1660-4601/17/3/754 https://www.mdpi.com/1660-4601/17/3/754
    - jeffbee 4y ago
      Sure but NOx from on-road vehicles is on a strong down-trend and has been for many years. Here's a detailed treatment of health effects from air pollutants. https://www.baaqmd.gov/~/media/Files/Planning%20and%20Research/Plans/PM%20Planning/ParticulatesMatter_Nov%207.ashx https://www.baaqmd.gov/~/media/Files/Planning%20and%20Resear...
8f2ab37a-ed6c 4y ago
How do we reduce tire particles being released during regular operation? Better materials? It seems like there's only so much we can do about the asphalt ultimately having to make contact with something with high friction.
- xnx 4y ago
  Smoother driving reduces particulates (e.g. no jackrabbit starts, smoother stops, less braking overall by avoiding situations like tailgating). I don't expect any humans to become better (they're getting worse), but self-driving cars will be much more fuel and braking efficient.
- zardo 4y ago
  > Better materials? It's possible there is a lot of low hanging fruit here, as tire particulate emission is not regulated.
  - 8f2ab37a-ed6c 4y ago
    That's a good point.
anonporridge 4y ago
One potential solution to tire particulates is direct capture. https://www.imperial.ac.uk/news/195595/worlds-first-device-capture-harmful-tyre/ https://www.imperial.ac.uk/news/195595/worlds-first-device-c... If these work and scale, it might behoove us to start requiring them in new cars, and maybe require retrofitting old cars.
timbit42 4y ago
As long as the tire and brake wear isn't creating CO2 or methane, I'm not so worried about it.

ceejayoz 4y ago

> Electric cars certainly reduce particulate emissions a lot further, but tire and break wear has become a significant part of particulate emissions. Doesn't regenerative braking reduce both tire and brake wear?

avelis 4y ago
Brake wear for sure.
ihattendorf 4y ago
Brake yes, I don't see how it would help tire wear (assuming you slow down at the same speed). Electric cars typically have higher tire wear because of the increased weight + typically higher torque/acceleration.
- ceejayoz 4y ago
  https://www.nokiantyres.com/company/news-article/there-is-a-common-misconception-related-to-electric-cars-in-reality-tires-will-last-for-a-long-time/ https://www.nokiantyres.com/company/news-article/there-is-a-... > Tires on a modern electric car will wear down much slower than in a car with a traditional internal combustion engine. This is due to good traction control. The driver assist systems reduce slipping by utilizing the electric motor's rapid power adjustment. This system is much quicker than in ICE vehicles, where it is based on braking and limiting engine RPM, Liukkula says. I dunno if anyone's done a good scientific study on this.
  - AnthonyMouse 4y ago
    In addition to this, people are aware of the existence of regenerative braking, and that it works better when decelerating less aggressively, so they do. Which puts less wear on the tires.
  - Gordonjcp 4y ago
    Sounds like shit to me. How much time do you spend spinning your tyres and braking so hard you skid?
    - deleted 4y ago
      [deleted]
    - ceejayoz 4y ago
      You don't have to fully skid the thing to see a benefit from better control over the breaking process. From the skid marks I've seen on the highway, rare skids seem to pull off a significant amount of rubber in one incident.
    - sokoloff 4y ago
      The tires cannot generate any longitudinal acceleration with zero slippage. This slippage is what causes wear. (As a driver, though you perceive there to be zero slippage without wheelspin or sliding the tires, there is slippage between the road and tire anytime the tire is exerting a longitudinal force on roadway.)
  - smachiz 4y ago
    This was, in my experience, not true. Ask most Tesla owners as well. The heavier car + much better acceleration created more tire wear than any improvements to traction control from faster power response (though I'm not sure intrinsically why that would reduce wear - ICE cars can apply brakes to a slipping tire just as well as an EV, and instant torque doesn't feel like it would do anything positive for tire wear). Fitting lower rolling resistance tires on ICE cars would provide any of the same benefits that EVs receive.
    - 4y ago
- rob74 4y ago
  Anecdotal evidence: I regularly manage to (unintentionally) spin the wheels in a petrol car, but I have never managed to do it in an electric car yet, despite trying out the full acceleration. So while the torque is undeniably greater, apparently the motor management control is also better, so it can deliver maximum acceleration without increased tire wear - at least in the electric cars I have been driving (mostly BMW i3).
comte7092 4y ago
Brakes certainly, but all motion still needs to be stopped through friction against the ground. EVs are significantly heavier for the time being, so if anything they have greater wear on tires all else equal.
- malfist 4y ago
  Is that true though? Energy has to go somewhere, but if you store a large part of that energy into batteries, doesn't that take away from what you have to expend on friction with the road? After all, energy can't be created or destroyed. So if you're storing it in batteries, it's coming out of your forward momentum.
  - SamBam 4y ago
    Energy that would normally have been lost in heating up/destroying the brake pads instead goes into the battery, of course. But I don't see why this alone would affect the tire tread.
  - comte7092 4y ago
    You aren’t regaining 100% of the kinetic energy so a significant part has to be lost somewhere else. Realistically regenerative braking is recouping energy that would be lost as heat when the friction brakes act on the wheels. However it would not stop a vehicle on a zero friction surface, as a simple example, so no it doesn’t take away from the friction heat losses on the road.
  - deleted 4y ago
    [deleted]
  - rootusrootus 4y ago
    > Is that true though? 100%. Brakes do not stop a car, tires do. Brakes just manage the energy. Putting it back into a battery so it can be used to accelerate again is great, but it's still the tires stopping the car.
    - mlindner 4y ago
ewgoforth 4y ago
Brake wear yes, but the resistance to forward motion still has to be transferred via that tires.
malfist 4y ago
Quick google says regenerative breaking has ~65% efficiency at energy recovery, but that includes the 10-20% lost when converting stored energy back into kinetic energy. So it sounds like regenerative breaking would covert ~75%-85% of kinetic energy into stored chemical energy. I'd expect to see similar reduction in tire and brake wear as well, maybe even more it probably depends on how break dust is generated, if it has a curve where more is generated with greater breaking force applied, by dropping the force on a break pad to 15% of it's previous value we might see an even greater reduction. This is all speculation though, I am not a physicist.
- qqtt 4y ago
  The energy efficiency of turning regenerative braking into energy isn’t really related to how regenerative braking can fully stop a vehicle without using the brake pads. Even if the regenerative braking energy efficiency were 1% - if it fully stops the car without using a brake pad that entire wear & tear (& dust) goes away.
  - vagrantJin 4y ago
    Thanks for pointing this out. Many arguments here are about regenerative braking - which does not the address the issue of tire wear.
hn_throwaway_99 4y ago
Absolutely. I have an EV that has an "aggressive regenerative braking" setting where pulling your foot off the accelerator slows the car considerably. In that setting I almost never touch the brake.
- jeffbee 4y ago
  Putting your foot on the brake pedal has almost nothing to do with whether the friction brake is engaged in an EV or hybrid. A computer decides when and how much to pressurize the friction brakes.
  - hn_throwaway_99 4y ago
    That's true, but my point is that, at least in my car, taking your foot off of the accelerator does not ever engage the friction brakes, and when I drive it's nearly 100% "one pedal driving". What you're saying, that when you do press the brakes that a computer decides how much to apply regen vs friction, is true, but again, my point is that I don't touch the brakes.
  - sliken 4y ago
    Depends on the car, the Tesla default setting is not use brakes when you life the throttle or use regeneration when you hit the brake. This lets you control how you slow down, which makes it easier to be nearly 100% regenerated.
deleted 4y ago
[deleted]
giardini 4y ago
Regenerative braking will reduce brake pad wear since part of the power otherwise dissipated as braking friction between pad and disc/drum is captured by the motor/generator, converted to electrical power and stored. Tire wear should be unaffected provided the e-car has a "freewheeling" feature whereby braking is not applied unless the driver hits a brake pedal. If the e-car is set to always run in a regenerative braking mode (brake goes on if driver eases off the "gas" pedal) then the braking will actually increase tire wear.

rqtwteye 4y ago

I agree about tire and brake wear but the air in cities will be incredibly better with only electric cars.

Gordonjcp 4y ago
You could just run ICE-powered cars on cleaner fuels like propane. There's a reason warehouse forklifts - which drive around inside completely enclosed buildings - run on propane.
- brianwawok 4y ago
  I’d prefer nothing out of tailpipes vs “cleaner combustion”
- mlindner 4y ago
  > You could just run ICE-powered cars on cleaner fuels like propane. From my understanding a lot of the pollution is just from heating up the incoming air containing nitrogen. Unless you're taking your oxidizer with you rather than using the air to burn that propane, you're still going to produce toxic-to-humans nitrogen-based oxides (pollution) from exploding the gas in the presence of nitrogen. In fact depending on how you do it (for example if the combustion temperatures end up higher) you could have significant increases of such compounds versus gasoline combustion. Best to keep the combustion vehicles to antiques/collectables and make all daily drivers use electricity.
  - Gordonjcp 4y ago
    Burning propane in car engines produces carbon dioxide and water, no sulphur oxides (because there's no sulphur in the fuel, or such a tiny amount that it is negligible) and no nitrogen oxides. You can actually measure this. It burns leaner than petrol resulting in complete combustion so there's no CO or HC in the exhaust, either. Indeed, if there's enough CO and HC in the environment from other vehicles you'll actually be burning that too giving it (in a sense) negative emissions figures.
- rqtwteye 4y ago

scythe 4y ago

It seems like everyone has become an expert on tire particulates over the last five years. You can't read a thread about EVs without hearing about it. But NOx emissions are actually more strongly correlated with many health outcomes, e.g.: https://www.mdpi.com/1660-4601/17/3/754 https://www.mdpi.com/1660-4601/17/3/754

dahfizz 4y ago
With particulate sensors becoming a cool new toy, I think a lot of people have the misconception that all particulate matter is the same (because that is all they can measure, so they focus on that one number). They don't stop to think whether the particles themselves are water droplets, poisonous chemicals, or something in between. I've had people tell me that campfire smoke is more deadly than cigarette smoke, because the campfire has more particles.
legulere 4y ago
Your study is only about asthma and bronchitis This study estimates that the disability adjusted life years lost by PM2.5 are orders of magnitude higher than from NO2: https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.1104035 https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.1104035 see figure 3 I'm fully agreeing that electric cars reduce pollution, I also ordered one myself. But they do not fully solve the pollution problem and reducing our dependency on cars is the most effective way to reduce negative effects.

jasonwatkinspdx 4y ago

About a decade ago I worked for 6 months in a temporary office near a very heavily trafficed overpass. This office didn't have AC (not exactly uncommon in the PNW) so we had the windows open during the summer. The amount of particulate that would build up on everything in just an hour was pretty dumbfounding.

electrondood 4y ago

EVs have next to zero brake wear. They do chew through tires faster due to increased torque. A lot of the particulate consists of petroleum parts, catalytic converter, etc. Components that EVs just don't have.

jeffbee 4y ago
Characterizing "a lot": according to the Bay Area Air Quality Management District, particulate emissions from on-road gasoline vehicles consists of 20% tailpipe emissions and 80% brake, tire, and resuspended road dust.
- dahfizz 4y ago
  > particulate emissions I think that's kind of obvious, as most tailpipe emissions are gaseous, not particulates. What really matters, instead of blindly counting particles, is health outcomes. Nox fumes are strongly associated with negative health outcomes, even if it isn't strongly associated with a particulate count.[1] [1]https://www.mdpi.com/1660-4601/17/3/754 https://www.mdpi.com/1660-4601/17/3/754
  - jeffbee 4y ago
    Sure but NOx from on-road vehicles is on a strong down-trend and has been for many years. Here's a detailed treatment of health effects from air pollutants. https://www.baaqmd.gov/~/media/Files/Planning%20and%20Research/Plans/PM%20Planning/ParticulatesMatter_Nov%207.ashx https://www.baaqmd.gov/~/media/Files/Planning%20and%20Resear...

8f2ab37a-ed6c 4y ago

How do we reduce tire particles being released during regular operation? Better materials? It seems like there's only so much we can do about the asphalt ultimately having to make contact with something with high friction.

xnx 4y ago
Smoother driving reduces particulates (e.g. no jackrabbit starts, smoother stops, less braking overall by avoiding situations like tailgating). I don't expect any humans to become better (they're getting worse), but self-driving cars will be much more fuel and braking efficient.
zardo 4y ago
> Better materials? It's possible there is a lot of low hanging fruit here, as tire particulate emission is not regulated.
- 8f2ab37a-ed6c 4y ago
  That's a good point.

anonporridge 4y ago

One potential solution to tire particulates is direct capture. https://www.imperial.ac.uk/news/195595/worlds-first-device-capture-harmful-tyre/ https://www.imperial.ac.uk/news/195595/worlds-first-device-c... If these work and scale, it might behoove us to start requiring them in new cars, and maybe require retrofitting old cars.

timbit42 4y ago

As long as the tire and brake wear isn't creating CO2 or methane, I'm not so worried about it.