Examining Electric Cars & Particulate Matter


smart fortwo electric drive

smart fortwo electric drive

There have been record numbers of articles written in 2015 referencing Inside EVs as the source for cumulative EV sales.

So, it was a bit disheartening to read an article posted by Mellisa Lott in the Scientific American referencing 300,000 EVs in the US and counting, while the current US count is just shy of 400,000. That is just a little more than an acceptable margin of error.

The author then posted “Why EVs can reduce (but not eliminate) urban air pollution. It’s time to look beyond the tailpipe”

The author produced the table above to point out how the particulate matter pollution produced by, tires, brakes, and road wear was much greater than from exhaust emissions of an ICE, thus concluding the environmental damage of an EV.  The following source link was provided as the basis for the table, though it is our opinion that the derived conclusions may be off by the comparable measures as the reported cumulative EV sales.

For starters, there is no consideration for regenerative braking under brake wear for urban driving. Nothing is pollution free, and particulate matter is a serious issue worthy of public conversation. It would have been noteworthy to point out how hybrids and EVs, are greatly reducing particulate matter through regenerative braking.

Furthermore, if you are going to write about EVs and pollution, should your table not include EVs and more than just one compound from exhaust emissions? Nowhere in the article could the reader understand how much an EV can reduce pollution.

Particulate matter is known as a contributor toward premature deaths from exhaust emissions, brakes, tires, and roads, though civilizations have turned a blind eye in favor of advancements brought since the dawn of the industrial revolutions. The particulate pollution created from your electrical source matters just the same as that from your tail pipe.

When EVs can receive their power from a renewable source, their emissions truly are zero. Already many EV drivers are saying YES to renewable sources to power their PEVs.  Additionally, if hybrids and PEVs can reduce particulate pollution through regenerative braking, then once again, EVs are saving lives.

Yes, EVs have tires and use the roads, but their environmental benefits are worth our adoption today. As for tires and roads, it may not be long before we start by looking at their composition, and begin the conversation towards different manufacturing materials.

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43 Comments on "Examining Electric Cars & Particulate Matter"

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Quoting from the article:
“According to these data, 55-95% of particulate matter air pollution (PM10) from cars driving in urban areas isn’t actually from the tailpipe”

So half or all basically. Seem like a rather large range no?

Also, no discussion of CO2, no mention of regen braking effect of brake pad wear. The diesel numbers are certain to be wrong given Dieselgate.

The article reads like the worst backhanded compliment to EVs.

Quoting from her 300,000 EV article:

“In terms of other types of air pollution – namely particulate matter (PM) and nitrogen oxides (NOx) – while EVs won’t eliminate pollution from vehicles, they would certainly help (a lot).”

She’s implying that EVs emit NOx by putting PM and NOx together in the sentence like that. Yet it’s clear that NOx only comes from exhaust emission.

Eric Cote

“According to these data, 55-95% of particulate matter air pollution (PM10) from cars driving in urban areas isn’t actually from the tailpipe”

Guess they didn’t measure Volkswagen diesel tailpipes…

Kootenay EV Family

Too bad she focused on PM so much in the paragraphs above the table, and left the largest finding until the second last paragraph – comparing to PM health effects, “While these numbers might seem high [for PM], they are much lower than the annual premature deaths resulting from exposure to nitrogen dioxide (NO2), a type of NOx pollution”.

Since the EV 100% eliminates NOx from the urban environment, and as you pointed out Mark, regenerative braking is not accounted for and could reduce PM itself significantly, you would think the article balance would be that EVs would significantly improve health outcomes for populations living in cities. (And that isn’t even accounting for SOx.)

And really that is only when comparing to a gasoline car – compared to a diesel car, the balance is heavily in the EV favour – which you would think would be important to highlight in diesel-centric Europe!


“Uncontrolled gas turbine NOx emissions are in the 150–300 ppmv range (about 300–600 mg/m3). Sometimes rules are based on a pollutant mass per unit heat input, such as lbs/MMBTU or grams/GJ.”
A lot of the new installations are gas turbine, thus there is a good chance the EV may be charged by one.


Are the turbines far enough away from the urban center to save it from bad effects?


I have seen turbines near industrial parks with thousands of employees nearby. Dilution is no solution to pollution, NOX is NOX.

Coal fired power plants put out arsenic, mercury and sulfur particulates. China and India use coal, I don’t think EVs in China charged with coal will solve the problem.

bill howland
Oh, c’mon that’a a Canard…. A modern US coal plant traps 90% of the mercury and 98% of the Sulfer-Dioxide. Even the sludge (as long as your coal plant isn’t run by the gov’t) is recycled into Formaldehyde-Free Drywall. Too bad Lowe’s purchased the Chinese stuff that ruined all the copper in the houses it was installed in. As far as pollution goes – places with bad problems historically such as Los Angeles had decades upon decades to plant a few trees to catch the rubber run off. Their extensive root systems apparently do a decent job of digesting the rubber. So the question is, why don’t they? Yes trees occassionally get into sewers, but with modern sch 40 DWV PVC, the roots don’t seem to cause the problems they used to. Still, it keeps Americans (Plumbers) working. More than one plumber has told me trees are his best friend, for all the sewer excavation they have caused when replacing old clay pipe sections. China is learning quickly to take pollution controls seriously, and to enact meaningful regulation. They also have a habit of executing CEO’s who cause problems, such as the baby deaths that ensued when one company started… Read more »

You think India and China trap particulates?

bill howland

No, India and China *do not* have enforced pollution controls. My point is, they WILL HAVE THEM, even if they’re kicking and screaming into it.

Even Canadians, who presume they are so much cleaner than Americans, didn’t have the strict Pollution Controls on their Coal Power Plants that Americans do (OF COURSE, Now Ontario Province has rid themselves of them).

When Buffalo was getting some pollution years ago, it was always assumed it was coming from the Huntleigh coal plan in tonawanda 4 miles away.

NOT TRUE! Investigation revealed it came almost totally from the Canadian Nanticoke Coal fired plant 50 miles west of Buffalo.


A large amount of toxic mercury pollution is released from a relatively small number of plants.
These 25 plants alone are responsible for nearly a third of all mercury emissions in the power sector, while providing only eight percent of our electricity.
Twenty of them are located within 50-100 miles of some of the largest metropolitan areas in the country, including Chicago, Dallas, Houston, Atlanta, Minneapolis, Detroit, Pittsburgh, Cleveland, St. Louis and Austin.
Texas led the nation in mercury air pollution from coal-fired power in 2009.

Kevin Z

All ice vehicles burn oil. Is that accounted for?


1. Worthless emissions data from 2012. You could at least quadruple the Nox values for diesels.
2. Roads are not relevant as all vehicles use roads. Most road wear is caused by heavy duty trucks, of which a statically inconsequential number are electric.
3. As mentioned, much less brake wear in evs, due to regenerative braking.
From the aricle:
“But, when taking a closer look at the data, it becomes clear that EVs would not eliminate the majority of local particulate matter emissions.”
So based on false data, according to the statement about evs do not produce 51% less particulate pollution. They could produce 50% less and that statement would still be correct. Again she is only talking about particulates which are only part of our air pollution problem.

A poorly written article based on outdated inaccurate data reaching specious conclusions. I would not want to go off, reach a conclusion, on the basis of false data.


A possible preview of the next article in the series by:
Melissa C. Lott is an engineer and researcher who works at the intersection of energy, environment, technology, and policy.
(I know that intersection, its dangerous).

Amish Buggies pollute as much as cars.
1.Horses evacuating (farting) contributes to global warming and smells bad.
2. Buggie whips and carriage components of tanned leather, noxious fumes.
3. Clip-clop of horse hooves create sparks and damage the pavement.

bill howland


The Amish horses I’ve driven past in my Roadster when purchasing their legally-sold Milk do more than just FART..

And my old-fashioned Roadster had incandescent lights for everything but the LED tail lights, whereas all Amish Buggies now have supermodern LED headlights.


I’m a cyclist, and I’ve long been an advocate for cycling as a perfect mode of transportation for a variety of tasks, but I also understand why some people aren’t as hardcore as I am in my willingness to ride in all four seasons. The very reasons she didn’t ride into work today are the very same reasons nearly nobody is going to do that every day. But that aside, cycling would be about the only acceptable solution to the problem as Melissa sees it. And she knows it has its own flaws.

Plus, there’s an old engineering axiom: “Better (or best) is the enemy of good.”

EVs are a good but imperfect solution to the pollution that cars produce. Electric transportation is also necessary if we’re going to completely get off of fossil fuels, so we need to do the work of generating electricity without fossils alongside the work of electrifying transportation. Doing both of these jobs at the same time will improve the pollution problem from both sources, and at roughly the same rate. The fact that the problem still remains at one end of the chain doesn’t mean that it’s not worthwhile.

Robert Weekley

Brave, the [Plus, there’s an old engineering axiom: “Better (or best) is the enemy of good.”] I believe is more like “Perfect is the enemy of better”, with the point being, “If it’s not yet perfect, let’s not do something that is better in the meantime.”

Similar to the arguments of BEV Range not being long enough, or, EV’s don’t go 500 miles (or 400 miles, or 300 miles, etc.) on a charge, so ‘Not Good Enough’.

Then when they get that range, the argument either moves to a higher number for range, or a lower cost argument. “Not Cheap Enough!”


If what you’re trying to say is that the perfect solution never comes, but a better one here and now is better than that perfect solution, then yes.

In no small part because perfect is never going to happen. Incremental improvements are better than doing nothing at all.


Or that xxx range is not recharged fast enough… kicking the can down the road…

bill howland

I ride a bike one or two miles per day when the weather allows, and if more people did it would help alleviate the current Diabetes epidemic.

They say bike riding has more health benefit for the least perceived effort than almost anything else.

Dave K.

I’m a bicyclist also but that doesn’t make my 40 mile commute possible, for that I use my EV. I think you got it right, the author has an anti car agenda and EVs are good enough that she feels threatened. I have run into this before and perhaps she is technically right, but people are just not going to give up their cars, just like they are not going to give up their air conditioners, eating meat, or any of a number of other “Luxuries” that have become necessities. So we need to make them as clean as possible, trying to change human nature is folly.


Where is the evidence that PMs stay in the air? Heavier ones (like brake dust) would silt out and end up in lakes and oceans. Even lighter ones would precipitate out of the air during normal rain/snow events.

Here in Texas, dust storms and pollen cause more health issues than pollution in non-city areas.

Yeah, moving pollutants from air to water is no solution, but at least you’re not breathing them.


Yes, that’s another fallacy in Ms. Lott’s assumptions. Thanks for pointing it out. Soot is so noxious partly because it hangs in the air so long. Other, larger and heavier particles are going to fall out of the air sooner.

I’d like to see a study of how long brake dust particles hang in the air. My guess is: on average, not long.


On natural gas, I found this Calpine link. Its coal numbers are reasonable (a little high), but they make natural gas electric power much better than gasoline and diesel:
Pretty sure EVs are worse, on NOx, if run only on, mythic, all-coal power. Not always true, but often. Coal NOx will continue to be scrubbed to lower values.
Most EVs are closer to 3 miles per kwh, than 2, or 4. The Tier 2 bin 5 regs, VW blew off, were for .07grams/mile. From there, we can appreciate how tough the US and Euro 6 regs have gotten, and how successful urea injection has become (when used…). Coal plants do it in a similar way (SCR/SNCR).

Take a 2.0 Vokswagen, or Audi, TDI times 40X, you get .07(40)= 2.800gr/mile
At 2lb/MWh coal, a 3mp/kwh EV = 0.302gr/mile

Note, that’s between EPA regs and what VWs put out (.07<.302<2.8). I used 2lbs, not 4, from NRDC data which accepts (more than Calpine advertises) that US coal's numbers are better than Calpine's.


Ev’s are the the Cleanest & safest form of transportation today.IF we all Revert to horse & buggy , Some Einstien Will come up with some QUACKED UP theory that Horse Farts Are causing green house gases & polute more than Car exhaust gases… ..Just to get attention..L M A O…Give it Up Already! These Knowit alls need a team Medical professional, to get their heads Screwed back on right! With Lot of ongoing Therapy to follow…..Give it a Rest!!!!!


Sad to see such poor science in Scientific American, altho this is far from the first occurrence I’ve seen pointed out. It’s rather silly to merely measure the volume of particle emission and conclude that one type of particle is as great a health hazard as another. Just as silly as noting that drinking isopropyl alcohol is bad for your health, and that like water it is a liquid, so drinking water must be bad for your health.

For example, altho there are many claims about health hazards from tire particles, it hasn’t been established that they actually are a significant health hazard. According to an ABC News report: “Even today, after over a century of using rubber tyres, we are not still not sure of the exact health hazards of the rubber from the tread of tyres.”


If one actually follows up on the source document that SA uses for the London PM “death count”, they will find that a) it is the PM2.5 that is the culprit, and b) that most anthropomorphic PM2.5 causing the London deaths comes from OUTSIDE the London area, not generated by internal sources (like cars). The source article doesn’t cite the outside sources. One interesting “source” pulled out of the calc was local airborne sea salt. A causative agent, but not human-sourced. Total Anthgo PM2.5 was estimated at 1.4 micro grams/cubic meter. Sea salt was 0.55, or about 35%. I bet if we did the numbers, we’d find that the total contribution of all ALL brake, tire, road wear PM2.5 is less than the air borne sea salt. Oh, and though PM10 is referenced a lot in the SA article, the source death-count study in London all referenced to NO2 and PM2.5. OK and for EV’s. Subtract brake dust from the count. (anyone had an EV brake job lately?) Tire and road wear probably a lot less than regular cars (isn’t that one thing that low rolling-resistance tires buys you – less road friction, less road and tire – or is… Read more »

HVACman said:

“isn’t that one thing that low rolling-resistance tires buys you – less road friction, less road and tire – or is the tyre – wear?”

Most of the rolling resistance from tires comes from sidewall flexing; the flexing causes loss of energy as waste heat. Engineering the tire to reduce flexing wouldn’t reduce friction, and I doubt that it would significantly reduce emission of tire particles.

Actually, reducing friction between tire and road would be nearly the last thing you’d want in a tire. Low friction is what makes driving on ice so dangerous.

But it’s a fallacy, and very poor science, to claim that tire particles are as dangerous as soot from gasmobile exhaust, or even worse: diesel exhaust. If tire particles really were a strong health hazard, I think by now a clear link between health and tire particles would have been established.


Another point missing is evaporate emissions from the gasoline itself. When refueling a gasoline car, or even when it’s sitting parked, there are a fair amount of VOC’s released.


Yet another story from an academic sounding writer where the data is good but the conclusion is wrong or rather the interpretation of someone else’s study is wrong. The Kings college report is absolutely recommending that London should electrify its transport network from both a cost and health perspective.

If brake dust and road wear are a significant % of the pollution then we should minimize these, that doesn’t mean we should ignore the other sources of pollution. She does write in her article that there are more deaths from NOx than PM10’s, all she is really saying is that EV’s would save billions of dollars in health care costs and eliminate 1000’s of unnecessary deaths but are not perfect.


BTW the report from King’s College showed that road pollution cost’s more than $2 billion USD in health care costs,

Scott Franco

“scientific american” ceased to be unbiased decades ago.

Too bad too. I grew up with that magazine. Watching them turn into far left loons turned my stomach. Now they mainly produce whiny environmental lectures aimed at people with the intelligence of a peptide.


Did you ever consider that it wasn’t Scientific American that changed, it was you that changed into a cranky old man screaming “Get off my lawn!”.


Am i the only one that clicked because of the picture of the sea turtle?


Good to see S.A get rightly criticised here but has anyone put in a complaint to the editor that get the article either corrected or taken down? If it’s false/ based on false data, it needs changing.


The numbers for P10 particulates don’t sound realistic. It the claim seriously that tires, brakes, and the road all wear at the same rate?


I want the Tesla Model S P90D(L) in dark blue with an all- black leather interior and the panoramic sunroof.

Call me particular.

Edward Arthur

Here’s your chance to own one (or nearly all of one, you had to say L) – http://climate-xchange.org/tesla-raffle/

EV Driver

Kind of missing the forest for the trees. Particulate matter kicked up by a car is not what is going to irreversibly damage our planet’s atmosphere. Maybe we should focus on the more important problems first.


Looking forward to the next article from Scientific American where they bust the myths on how EVs won’t reduce light pollution caused by headlights and street lamps.


Have you not visited London? The roads are so often damp, especially at this time of year, I doubt if there’s much particulate from tyres is in the air. Presumably this particulate gets washed down the drains when it rains (frequently).

My Renault Zoe has Michelin EV tyres and the wear rate appears to be a lot lower than any other tyre I’ve ever had fitted to a car. Over 8000 miles the front tyres have worn about 0.7mm!


Scientific American should be ashamed for not rejectING such a poorly researched article

bill howland

Since I’m not worried about plant food, Pseudo-Scientific Articles in Scientific American are nothing new to me.

I always remember the one from around 2 decades ago that said that any large amounts of EV’s were impossible, since there simply wasn’t enough copper for the connector to charge the battery.

He was assuming a 14 kw rate was MANDATORY, and therefore, since the 12 volt battery charged at around 14 volts, a 1000 ampere connector was required at the car, and the copper block required simply used too much to be even possible, seeing as the amount of cars on the road and the amount of copper mined annually.

Now this guy must know what he’s talking about because he has a Doctor of Philosophy in electrical engineering, and insists on being addressed “DOCTOR”.

Of course, GM released the “Copper Blockless” magnetically charged EV1 the same year. Good thing they didn’t read his article, or maybe they did, and laughed as I did.