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Pollution from tire wear is worse than exhaust emissions?

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Re: Pollution from tire wear is worse than exhaust emissions?

#251

Post by gambiting »

Fjolsvith wrote: post #241
gambiting wrote: post #235

Earlier quoted context omitted.

I cannot believe a studded shoe would have any impact whatsoever on a concrete pavement. Human weight is nothing compared to that of a car.

By your logic, water running across concrete wouldn't create any wear on the concrete, but in truth, it does.

Yeah, but there's a lot of water, and it can run over concrete for hours if not days at a time - of course it has an impact simply due to the sheer volume of it. Again, how does it compare to the miniscule impact of studded shoes?

Re: Pollution from tire wear is worse than exhaust emissions?

#252

Post by gambiting »

ars wrote: post #246
gambiting wrote: post #235

Earlier quoted context omitted.

I cannot believe a studded shoe would have any impact whatsoever on a concrete pavement. Human weight is nothing compared to that of a car.

The ground pressure of a human wearing studded shoes is an order of magnitude or more higher than the ground pressure of a car. The ground pressure of a car is exactly equal to the PSI that you inflate the tire. Take the weight of a human and divide by the surface area of of a started shoe you will find a significantly higher number.

>>The ground pressure of a car is exactly equal to the PSI that you inflate the tire

Wait, what? So if the tire is flat, the car exerts no pressure on the ground? :-P

Re: Pollution from tire wear is worse than exhaust emissions?

#253

Post by toxik »

kungtotte wrote: post #173
ratel wrote: post #164

Hold on: The claim is this: > "Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles." It does not seem to be a mistake: > "Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000." A tire might way up to 15 kilograms f…

They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road. There's been studies done here in Sweden since we've banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don't know of any sources in English off the top of my head though. The last time I read an article about it though (2+ years ago, d…

We have not banned diesel engines in Stockholm at all?

Re: Pollution from tire wear is worse than exhaust emissions?

#254

Post by ars »

kungtotte wrote: post #173
ratel wrote: post #164

Hold on: The claim is this: > "Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles." It does not seem to be a mistake: > "Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000." A tire might way up to 15 kilograms f…

They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road. There's been studies done here in Sweden since we've banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don't know of any sources in English off the top of my head though. The last time I read an article about it though (2+ years ago, d…

If the particles were coming from the road then roads would wear in very visible ways.

But we don't actually see that kind of wear. Roads don't typically have grooves on them where the cars go that are lower than the middle which doesn't have tires driving over it.

Re: Pollution from tire wear is worse than exhaust emissions?

#255

Post by ars »

gambiting wrote: post #252
ars wrote: post #246

Earlier quoted context omitted.

The ground pressure of a human wearing studded shoes is an order of magnitude or more higher than the ground pressure of a car. The ground pressure of a car is exactly equal to the PSI that you inflate the tire. Take the weight of a human and divide by the surface area of of a started shoe you will find a significantly higher number.

>>The ground pressure of a car is exactly equal to the PSI that you inflate the tire Wait, what? So if the tire is flat, the car exerts no pressure on the ground? :-P

I know you are joking but just to answer the question anyway, if the tires are completely flat then they are not supporting the car and you can't use them for measurement.

If the tires are partially flat then they are supporting the car and the PSI is correct and you'll notice the tire spreads out wider on the road so the ground force is lower because it's spread out over a larger area.

Technically you have to also include the springiness of the sidewall in the measurement not just the PSI of the air.

Re: Pollution from tire wear is worse than exhaust emissions?

#256

Post by Reason077 »

kungtotte wrote: post #173
ratel wrote: post #164

Hold on: The claim is this: > "Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles." It does not seem to be a mistake: > "Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000." A tire might way up to 15 kilograms f…

They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road. There's been studies done here in Sweden since we've banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don't know of any sources in English off the top of my head though. The last time I read an article about it though (2+ years ago, d…

> "the danger in the particles comes from their size with smaller particles being more dangerous for humans. And that road particles were something like an order of magnitude larger than exhaust fume particles from diesel engines."

Exactly. It might look bad when you compare the mass of particles, but if you compare the particle counts, it's exhaust emissions that produce the big numbers - of really tiny (sub-PM2.5) particles.

Re: Pollution from tire wear is worse than exhaust emissions?

#257

Post by xenonite »

saiya-jin wrote: post #222
kungtotte wrote: post #173

Earlier quoted context omitted.

They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road. There's been studies done here in Sweden since we've banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don't know of any sources in English off the top of my head though. The last time I read an article about it though (2+ years ago, d…

That doesn't make sense to me either. Take a busy German highway (as I don't know the average load on US ones), easily 100k cars per day. There are parts of highways which don't get replaced for 20 years easily. Plus apart from tiny fraction of north europe (and maybe Canada?), nobody ever uses studs. Back of the envelope math tells me 1 km of highway would lose some 730 tonnes of asphalt, per year (so 14,600 tonnes…

Indeed, trucks greatly damage roads. For example a 2 tonnes car has 2 axles, hence a=1 tonne per axle. A 20 tonnes truck with 2 axles has b=10 tonnes per axle. Then, the road damage per axle increases by a power of four [1], i.e., by (b/a)^4=10000.

[1] https://de.wikipedia.org/wiki/Vierte-Potenz-Gesetz

Re: Pollution from tire wear is worse than exhaust emissions?

#258

Post by hinkley »

blattimwind wrote: post #190
hinkley wrote: post #155

Earlier quoted context omitted.

Everything is killing us, but some things faster than others and so we have to prioritize, but hedge. Woodworkers have dust collection systems, air exchangers, and occasionally respirators, so they don’t get something akin to asbestosis from sawdust. What escapes gets processed by soil fungi so not a big problem. Microplastics have a possibility to do bad things to us over the long run by accumulating in our soils, a…

A lot of plastics are pretty much chemically inert under a wide variety of conditions though.

Probably true by themselves, although we just don’t know how many PBAs we haven’t figured out yet.

Plastics have a habit of accumulating some pretty bad chemicals like petrochemicals, PCBs, and possibly dioxins but don’t quote me on that one. So ingesting plastic in a lab setting and plastic in the environment may have quite different outcomes.

Re: Pollution from tire wear is worse than exhaust emissions?

#259

Post by reidacdc »

ratel wrote: post #164

Hold on: The claim is this: > "Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles." It does not seem to be a mistake: > "Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000." A tire might way up to 15 kilograms f…

Some discussion down-thread about this also, somebody runs the numbers for the road itself.

If the emissions numbers are right, it can't be matter that is being consumed or discarded, so it has to be matter that is being returned to the system and "emitted" again. Crap on the road itself meets this requirement -- a car drives by, throws up a bit of rubber off the tires, a bit of asphalt off the road, and a lot of junk from the road surface, and almost all of this stuff falls back on to the road to be thrown up again by the next car.

The article doesn't say how the measurements were done, so it's possible they sampled a small fraction of the air and measured the density, so having the junk available to the sensor doesn't necessarily rule out the recirculation idea.

But if the junk is mostly recirculating, then maybe the health threat is not as bad as if it's being emitted off the road and being lofted into the air with a long dwell-time?

Lots of things are possible and consistent with what the article states, evidently more research is needed.

Re: Pollution from tire wear is worse than exhaust emissions?

#260

Post by gambiting »

ars wrote: post #255
gambiting wrote: post #252

Earlier quoted context omitted.

>>The ground pressure of a car is exactly equal to the PSI that you inflate the tire Wait, what? So if the tire is flat, the car exerts no pressure on the ground? :-P

I know you are joking but just to answer the question anyway, if the tires are completely flat then they are not supporting the car and you can't use them for measurement. If the tires are partially flat then they are supporting the car and the PSI is correct and you'll notice the tire spreads out wider on the road so the ground force is lower because it's spread out over a larger area. Technically you have to also i…

>>if the tires are completely flat then they are not supporting the car and you can't use them for measurement.

Run-flat tires are a thing though - you can drive on them even with no internal pressure, there can be a gaping hole in it and you can still drive on them. So what's the pressure the car exerts on the road when driving then?

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