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Comment by ADSSDA | Hacker News Reader

Isn't most PM 2.5 pollution produced by brake pad and tire wear, which is made worse by EVs due to their weight?

> which is made worse by EVs due to their weight?

What a ridiculous supposition.

First the weight difference is not that huge, second EV's use regenerative breaking for a huge portion of their breaking spectrum bypassing break pads entirely.

Idk if you tried looking at any evidence when making your claim, but this clearly supports the gp and contradicts your statement [1] [2].

[1]https://www.ridef2.com/blog-del-direttore-ridef/will-electri...

[2]https://www.sciencedirect.com/science/article/abs/pii/S13522...

Idk, if you bothered to read the study that you are pointing to in your coup de grace, you'd would realize your cited sources admit that EV's create no more particulate pollution than ICE engines. Your cited study actually states that EVs do reduce particulate pollution but only by a couple percent, which is opposite of "creating more" for those who prefer evidence based positions.

It's almost as if regenerative breaking reduces break wear and compensates for the marginal increase weight as many other people have already pointed out?

The original GP's post had two points:

- most PM 2.5 pollution is produced by brake pad and tire wear

- which [i.e. PM 2.5 pollution produced by brake pad and tire wear] is made worse by EVs due to their weight

These are direct quotes from my links:

- "A large fraction (50-85% and up to 90%) of traffic generated PM10 and PM2,5 is not due to the exhaust emissions by the motor, but rather to non-exhaust emissions (brake wear, road wear, tyre wear and road dust resuspension)"

- "A positive relationship exists between vehicle weight and non-exhaust emissions."... "Electric vehicles are 24% heavier than their conventional counterparts."

What’s your point? That we should continue to favor gas cars over EVs? That cars should be taken off the road entirely? Something else?

My point was to defend ADSSDA's post against deeviant's claims.

Personally, I would like light EVs.

So en EV without a battery? They didn’t make them weigh more just because they wanted to.

I think it's just that EVs will not reduce asthma caused by small particle air pollution. They may in fact make it worse.

> "A positive relationship exists between vehicle weight and non-exhaust emissions."... "Electric vehicles are 24% heavier than their conventional counterparts."

Both are true. However, without factoring in decreased friction-brake usage in EVs (due to regenerative braking), this point is meaningless or deceptive.

The study cited to me in order to defend the point that EVs make more particulate pollution flat out found that EV's create less particulate pollution.

> A positive relationship exists between vehicle weight and non-exhaust emissions."

As others already pointed out, that is the same study, the same study that found that EV's create less particulate pollution. The more weight = more particulate emission part did not control for EV regenerative breaking. So your position is ignorant at best and disingenuous at worse.

This will be my last comment here on the account that I will not debate facts with random people on the internet. If you can't be bothered to read the study, don't cite it, don't reference it and for god's sake don't try to use it to say something that is literally the opposite of it's findings.

Brake. The word is brake.

I am dyslexic, I swap words like that frequently, shit happens.

But if that is all you have to add to this discussion, I wonder why you bothered.

Both those sources are the same paper, fyi. Found a PDF here: http://www.soliftec.com/NonExhaust%20PMs.pdf

And the claim is a bit dubious, imo. It looks like they're counting "resuspension" (kicking up existing settled PM2.5 in the wake) as a source.

The first link cites multiple papers, including the one in the second link. Looks like the study that mentions "resuspension" is a different study[1] than the one in the second link.

[1]https://www.sciencedirect.com/science/article/abs/pii/S13522...

People tend to assume that gasoline engines don't produce PM2.5, but that's apparently wrong. I saw some seemingly legit report that claims tire and brakes create about 10% of the PM2.5 pollution.

EV and Hybrid cars have regen braking which reduces brake pad wear. I don't know about PM2.5 but hybrids also emit much less NOx than straight gasoline cars.

These are idle cars which are not braking, so the PM2.5 here is purely the engine pollution. City life might not be affected as much, but school buildings with cars waiting outside will be!

If the ev has regenerative braking, the brakes actually last much longer than in ICE cars. Not sure how tires are affected but I'd imagine they do have a shorter life, and I'm not sure how the longer brake life balances with (probably) shorter tire life from a pollution perspective

Why would tires last longer in an ICE vehicle? I don't think tires care what makes them spin.

Electric cars are heavier due to the battery.

It depends on exactly which car you are comparing. The Tesla Model 3 is somewhere around 3500 lbs, isn't it? That's pretty average for a car these days.

And there are plenty of big SUVs that have a similar weight to the heavier EVs.

Besides, you can't assume that electric cars use the same tires as non-electric ones.

There is a huge range of tires out there from extremely long wearing ones to sticky ones that last a fraction of the time.

I believe tires last less time in an EV, because of the increased mass. But maybe that isn't the case. I just looked up a comparable ICE to a model 3, got the BMW 330i, and that has approximately the same weight (3500 lbs)

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