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Pollution from tire wear is worse than exhaust emissions?

emissionsanalytics.com

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

#301

Post by JangoSteve »

bigiain wrote: post #300
TheSpiceIsLife wrote: post #297

Earlier quoted context omitted.

Perhaps it’s mostly existing particles laying on the road that are thrown up by the next vehicle’s tyres as it passes?

That's a pretty long stretch from the claim: "we found that the car emitted 5.8 grams per kilometer of particles".

But is it a long stretch from the claim: "Non-exhaust emissions (NEE) are particles released into the air from brake wear, tyre wear, road surface wear and resuspension of road dust during on-road vehicle usage."

Resuspension of road dust is literally one of the 4 things they defined as the NEE they're measuring.

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

#302

Post by nvader »

This article, and the whole website looks so suspicious. Quotes come mostly from its own organization, "Emission Analytics", and there is no reference to an existing or upcoming publication.

In addition, and I realize I'm nitpicking, the stock photo, the composition of the copy and the general... feel of the website seems off.

The overall effect is to make me actively distrust their conclusions and want to ask about their agenda and source of funding.

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

#303

Post by mirimir »

gambiting wrote: post #260
ars wrote: post #255

Earlier quoted context omitted.

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?

I've done that. They catch fire, after a while.

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

#304

Post by nvader »

labawi wrote: post #238
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…

Study mentions EU and source company has offices in Stokenchurch, UK and Stuttgart, Germany. I doubt they tested with studded tires and called it typical. They did test with brand new tires - that's the likely source. "Emissions Analytics .. [self proclaimed?] leading independent .. specialist for .. measurement of realworld emissions .. performed .. initial tyre wear testing. .. on brand new, correctly inflated tyre…

I don't think you can call it a study. They say they performed, "initial testing".

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

#305

Post by WWLink »

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…

I would guess the measurement is more like how much dirt and dust is involved with a car driving driving down the road. Like brake dust, tire stuff.. and then that stuff being kicked up from the road surface by other cars and so on.

And yes it's super filthy and gross. I live on a busy street (but not a main street, so not THAT busy)... and my bathroom windowsills turn black after about a month because of brake dust and other car grossness.

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

#306

Post by telchar »

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…

A study linked last time this came up on HN indicated most of the particulate pollution is "resuspension", or previously generated particles kicked up by the car passing. It makes sense to consider in some cases but I think it's misleading to quote those numbers in some contexts, leading to confusion like this.

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

#307

Post by jessaustin »

reitzensteinm wrote: post #231
jessaustin wrote: post #203

Earlier quoted context omitted.

Yeah, they use dual tires so that they don't pop catastrophically, not to spare the road from wear.

I'm sure that's true, but are you saying it doesn't reduce wear?

It probably reduces wear slightly. Increasing contact area necessarily decreases applied pressure. Then again, a wider effective contact profile damages more of the road than a narrower one would.

Let's not forget the context of this discussion, however. Fourth power expressions are still fourth power expressions after multiplication by a constant factor. 4/18 is a constant factor.

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

#308

Post by bigiain »

JangoSteve wrote: post #301
bigiain wrote: post #300

Earlier quoted context omitted.

That's a pretty long stretch from the claim: "we found that the car emitted 5.8 grams per kilometer of particles".

But is it a long stretch from the claim: "Non-exhaust emissions (NEE) are particles released into the air from brake wear, tyre wear, road surface wear and resuspension of road dust during on-road vehicle usage." Resuspension of road dust is literally one of the 4 things they defined as the NEE they're measuring.

OK, I missed that bit.

But counting "resuspended road dust" as "emissions" seems pretty far fetched to me. Especially if that's a significant portion of the "5.8 grams per kilometer of particles", and you then push out a press release with the hyperbolic headline claim "Pollution from tire wear 1000 times worse than exhaust emissions."

And they then have the audacity to claim: "Emissions Analytics seeks to bring transparency to a confused market sector."

Pretty sure I know who's funding them now, without even bothering to google it...

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

#310

Post by reitzensteinm »

jessaustin wrote: post #307
reitzensteinm wrote: post #231

Earlier quoted context omitted.

I'm sure that's true, but are you saying it doesn't reduce wear?

It probably reduces wear slightly. Increasing contact area necessarily decreases applied pressure. Then again, a wider effective contact profile damages more of the road than a narrower one would. Let's not forget the context of this discussion, however. Fourth power expressions are still fourth power expressions after multiplication by a constant factor. 4/18 is a constant factor.

You're multiplying the input by a constant factor. If wear is proportional to (weight per tire)^4, and you've halved weight per tire by having twice as many, you've just reduced wear to 6% of its original value.

I don't know if doubling tire counts really does this, but it's hard to see why twice as many axles would help but tires per axle would not. It's possible (the pressure underneath the tires is reduced, but the tires exerting pressure on the road are closer together) but counter intuitive to say the least.

And there's no proof in this thread that it doesn't help except for masklinn's misinterpretation of the original study.

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