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Dust from car brakes more harmful than exhaust, study finds

e360.yale.edu

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Re: Dust from car brakes more harmful than exhaust, study finds

#51

Post by pornel »

deadbabe wrote: post #19

One solution could be to require ceramic brakes which produce far less dust and may be more environmentally friendly, and even has greater performance which EVs will need for their extra torque.

EVs on public roads must still obey the same speed limits and common sense behavior. Having more torque doesn't mean drivers have to slam brakes like on a race track.

In normal driving regenerative braking takes away most of the energy, leaving very little work for the friction brakes. Sometimes EVs even have the opposite problem — brakes rust due to very low use.

Re: Dust from car brakes more harmful than exhaust, study finds

#52

Post by jlnthws »

This is the regular current taboo. Micro-dust from tires and brakes contributes to half of an ICE vehicle’s pollution, with the other half coming from exhaust emissions. The amount of this micro-dust scales with a power of the vehicle’s weight, typically between the square and cube for cars, and up to the fourth power for heavy trucks. EVs are 30–60% heavier than their ICE counterparts. Assuming all other factors remain constant, EVs thus generate more particulate pollution than ICE vehicles. This does NOT even include the environmental impact of battery production and electricity generation.

Re: Dust from car brakes more harmful than exhaust, study finds

#53

Post by nullstyle »

jazzyjackson wrote: post #40
amazingamazing wrote: post #27

Earlier quoted context omitted.

You show me one of these that can be ridden [comfortably] in 2 degrees Fahrenheit with snow and ice everywhere and you have my money!

https://www.utahtrikes.com/PROD-11617955.html

That still wouldn't be comfortable

Re: Dust from car brakes more harmful than exhaust, study finds

#54

Post by prododev »

djaychela wrote: post #33

> with their increased weight and powerful torque, they produce a lot more tyre pollution than ICE vehicles. This has been shown not to be true in a number of studies.

Can you share them? Because physics says that damage to roads scales quadratically with weight. Not sure why tires would not experience a similar increase.

At the very least, these tires are subject to higher forces due to the heavier weights of EVs. Intuitively, consistently applying higher friction forces to an object would cause higher wear.

Re: Dust from car brakes more harmful than exhaust, study finds

#55

Post by ajmurmann »

vehemenz wrote: post #45
foobazgt wrote: post #17

Earlier quoted context omitted.

This is fake news. The backing study for this claim did all sorts of wonky unrealistic testing to come to this conclusion. If you own an EV, you viscerally know it's BS given that you're the one paying for the actual tire replacements on your real-world driven vehicle.

Heavier vehicles wear down tires faster. Visceral intuitions can't really compete with physics here.

When more so if they have more torque.

Re: Dust from car brakes more harmful than exhaust, study finds

#56

Post by ghaff »

krn1p4n1c wrote: post #34
t-3 wrote: post #24

Earlier quoted context omitted.

E-bikes are unusable at this time of year. It needs to stand stably on it's own to not kill me the instant some ice appears (so, four wheels) and have an enclosed cabin to stop frostbite.

I’ve biked to work in -15C. Get studded tires.

The vast majority of the population is simply not going to do that if they bike at all.

Re: Dust from car brakes more harmful than exhaust, study finds

#57

Post by tomrod »

thih9 wrote: post #50

I'm conflicted about declaring something as "more harmful" in such a narrow context. The article says that human cells react worse to dust from modern brakes than to exhaust or even dust from asbestos brakes. But this ignores the impact of exhaust on city pollution, or the hazards of asbestos production process, etc. I guess this only tells us that dust from modern brakes can be dangerous and we should keep an eye on…

PM2.5 is pretty bad. Implicated in exacerbating childhood asthma, heart disease, diabetes, and basically a ton of other issues.

Proximity to large roads (like US Interstates) is known to be a bit higher in PM2.5.

Re: Dust from car brakes more harmful than exhaust, study finds

#58

Post by chongli »

bfgeek wrote: post #26
foobazgt wrote: post #17

Earlier quoted context omitted.

This is fake news. The backing study for this claim did all sorts of wonky unrealistic testing to come to this conclusion. If you own an EV, you viscerally know it's BS given that you're the one paying for the actual tire replacements on your real-world driven vehicle.

To add to this, (from what I remember reading the study at the time) it was basically racing a car around a track (think lots of tyre squealing around corners), and found that the tyre wear was very high. I haven't seen a study which actually simulates somewhat "normal" driving (presumably because the wear is so low driving like that it's difficult to measure). Also didn't factor in a bunch of different stuff - tyres…

A normal driving test was (famously [1]) done to measure the effect of axle load (vehicle weight per axle) on road wear. This is where we got the “fourth power law” of road wear.

I think as a starting point, I would expect that tire wear should remain roughly in proportion to road wear, given the same tires on each vehicle. From this, I would expect car makers to use larger, thicker, heavier tires on heavier vehicles in order to compensate.

Thus I think we shouldn’t accept claims about the replacement lifecycle of tires without knowing these details of their construction. If an electric car is twice the mass of an older ICE car then the fourth power rule would predict a 16-fold increase in road wear. I would then expect the tires on the EV to have 16 times more rubber in order to last the same duration, unless they’re made of some newer compounds which are more durable.

[1] https://en.wikipedia.org/wiki/AASHO_Road_Test

Re: Dust from car brakes more harmful than exhaust, study finds

#59

Post by [deleted] »

amazingamazing wrote: post #27
digdugdirk wrote: post #25

Earlier quoted context omitted.

That's a great idea. And since it'll be limited to in town use, something narrower might be useful - maybe give it two wheels instead of four? That'd be huge for reducing weight and increasing range. And for suitable geographic areas, it might even be possible to make one light enough that it could be powered by the rider, no external power source required! Then, with the reduction in width required for these futuris…

You show me one of these that can be ridden [comfortably] in 2 degrees Fahrenheit with snow and ice everywhere and you have my money!

[deleted]

Re: Dust from car brakes more harmful than exhaust, study finds

#60

Post by ndsipa_pomu »

bluescrn wrote: post #28
ndsipa_pomu wrote: post #7

I think this is missing out on the big issue - tyre pollution which contains really nasty chemicals that inevitably get washed into rivers and waterways. Also, car-shaped EVs often use regenerative braking which will reduce the amount of brake dust pollution, but with their increased weight and powerful torque, they produce a lot more tyre pollution than ICE vehicles. https://earth.org/tyre-pollution/

Interesting that nobody every talked about tyre/brake dust until it became clear that cars aren't going away as we phase out fossil fuels, they're just going electric. Is this a serious environmental concern compared to the climate/emissions issue, or just the 'r/fuckcars mentality'? Meanwhile, here in the UK, one of the more interesting alternatives - personal light EVs (ebikes/scooters) are being utterly demonized,…

Also in the UK and I certainly subscribe to r/fuckcars as I'm a keen cyclist and never got around to learning to drive.

I find it annoying that media outlets (BBC - I'm looking mainly at you!) will refer to EVs as being car-shaped and then, as you said, demonise e-bikes by lumping them in with the illegal e-motorbikes (see the recent Panorama program for a clear case of not making clear the distinction between e-motorbikes and e-bikes).

As I see it, the biggest problems with cars are their size and weight. With electric propulsion, the weight is a problem as they have to propel the vehicle and the batteries which obviously means even more weight (though they're typically only slightly more than ICE cars). This also leads to the problem of the vehicles taking longer to recharge and thus requiring upgraded infrastructure to allow people to charge them quickly.

However, if we get as many people to use e-bikes or e-scooters, then the size and weight issues pretty much disappear. It's often feasible to have removable batteries, so the vehicle can be "recharged" instantly by swapping the battery (I believe this is very popular in some countries for food delivery riders). This also means that the battery recharging can be performed using a normal power socket without requiring upgraded infrastructure although it may be wise to keep an eye on the batteries whilst charging to prevent house fires.

Incidentally, Mrs ndsipa_pomu recently bought a good quality e-bike (i.e. not one of the duck-taped conversions) and absolutely loves commuting on it as she sails past the traffic that she was previously trapped in. Though it's limited to assist only up to 15.5mph, she finds it powerful enough to cope with the hills.

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