Pollution from tire wear is worse than exhaust emissions? • Hacker News Board

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

#41

Post by fefe23 » Sun, Mar 08, 2020, 2:42 PM UTC

furtive808 wrote: post #34

thinkcontext wrote: post #30

> 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. So this is based on n=1, very suspicious. If tires really were this big a source of PM emissions then how would levels in US cities gone down through vehicle pollution control measures. Something is not adding up here.

At that rate you would burn through the whole set of tires in less than 50,000km, so how is it possible? Could it be those nubs on new tires are accounting for a majority of the waste up front?

Maybe not all the particles come from the tyre?

They could come from the road, or the brakes, or leaves / dust on the road.

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

#42

Post by toss1 » Sun, Mar 08, 2020, 2:44 PM UTC

Yes, the tires wear, and the wear can be easily measured by the mass difference between a new tire, worn tire, divided by the distance. Plausible that the total wear is 1-3 orders of magnitude total mass greater than modern tailpipe emissions.

A huge question that is never answered is how much of those worn particles actually become airborne, how many stay airborne for how long, and what is their effect on organisms breathing them.

While the Precautionary Principle says we should assume harm, this entire article seems to assume that every microgram is automatically the most harmful possible pollutant, which is likely untrue, unnecessarily alarmist, and undermines their thesis.

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

#43

Post by [deleted] » Sun, Mar 08, 2020, 2:45 PM UTC

benkuhn wrote: post #21

the8472 wrote: post #11

Headline > Pollution From Tyre Wear [is] 1,000 Times Worse Than Exhaust Emissions Article > But tyre wear pollution is unregulated and can be 1,000 times worse

It's true that they weakened the wording in that section of the body, but the description of the actual research does make it sound like the factor of 1,000 was a typical case, not the worst case: > 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. > > Compared with regulated exhaust emission limits of 4.5 milligrams pe…

[deleted]

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

#44

Post by natch » Sun, Mar 08, 2020, 2:46 PM UTC

lazyjones wrote: post #26

This is, as it stands in the headline, classic "fake news" that is being spread by people who want to exaggerate the problems with cars.

We don't know who it is being promoted by. Possibly the oil industry or the legacy gasoline car industry.

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

#45

Post by abainbridge » Sun, Mar 08, 2020, 2:46 PM UTC

vinw wrote: post #27

benkuhn wrote: post #21

Earlier quoted context omitted.

It's true that they weakened the wording in that section of the body, but the description of the actual research does make it sound like the factor of 1,000 was a typical case, not the worst case: > 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. > > Compared with regulated exhaust emission limits of 4.5 milligrams pe…

5.8 grams per kilometer would mean in only 10,000 KM your tyres lose 58 Kg. Seems way off.

Yep.

Life of car tyre is ~40e3 km. 5.8g * 40e3km = 232 kg. Or 58 kg per tyre. A new tyre weighs about 8kg. I guess it might loose 3kg. So I think they've over estimated by about 20x.

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

#46

Post by pinko » Sun, Mar 08, 2020, 2:48 PM UTC

_Microft wrote: post #32

Maybe offtopic but a surprising bit of extra information regarding wear and vehicles: Road wear scales with the fourth power of axle load, so heavier vehicles do much more damage than one might expect. Take a 40t truck with 5 axles vs. a small car with a weight of 1t and two axles (e.g. VW Polo, maybe an older VW Golf might only weigh 1t as well): (8t axle load / 0.5t axle load) = 16^4, i.e. the truck puts 2^16 (6553…

I remember a civil engineer telling me once that if highways only had cars on them they would last 100 years between repavings.

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

#47

Post by ip26 » Sun, Mar 08, 2020, 2:50 PM UTC

Testing only a brand new tire seems like a serious limitation. What if, for example, tires shed particles in a bathtub curve, or exponential decay?

I find myself slightly suspicious they knew a new tire to shed the most and were going for that shocking headline.

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

#48

Post by muro » Sun, Mar 08, 2020, 2:51 PM UTC

Weigh used tires, compare to new, divide by distance used for. Wash them thoroughly if you want to be extra precise.

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

#49

Post by zip1234 » Sun, Mar 08, 2020, 3:02 PM UTC

pinko wrote: post #46

_Microft wrote: post #32

Maybe offtopic but a surprising bit of extra information regarding wear and vehicles: Road wear scales with the fourth power of axle load, so heavier vehicles do much more damage than one might expect. Take a 40t truck with 5 axles vs. a small car with a weight of 1t and two axles (e.g. VW Polo, maybe an older VW Golf might only weigh 1t as well): (8t axle load / 0.5t axle load) = 16^4, i.e. the truck puts 2^16 (6553…

I remember a civil engineer telling me once that if highways only had cars on them they would last 100 years between repavings.

I highly doubt this in cold areas but might be true elsewhere

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

#50

Post by seemslegit » Sun, Mar 08, 2020, 3:02 PM UTC

This talks specifically about particle pollution ( not CO2 emissions ) which has already been largely regulated out, "up to" 1000x of a very small amount can still be quite insignificant.

Given the misleading nature of the press release title I think I'll avoid reading the actual result and mentally mark "Emission analytics" as one of those companies.