Diesel is now better than gas, study says

July 14, 2017 by Jeff Heinrich
Credit: THINKSTOCK

Modern diesel cars emit less pollution generally than cars that run on gasoline, says a new six-nation study published today in Scientific Reports whose groundwork was laid in part by an American chemist now working at Université de Montréal.

And since is so much cleaner than before, environmental regulators should increasingly shift their focus to dirtier gasoline-powered cars and other sources of air , says the UdeM scientist, Patrick Hayes.

"Diesel has a bad reputation because you can see the pollution, but it's actually the invisible pollution that comes from gasoline in cars that's worse," said Hayes, 36, an assistant professor at UdeM.

"The next step should be to focus on gasoline or removing old diesel vehicles from the road. Modern diesel vehicles have adopted new standards and are now very clean, so attention needs to now turn to regulating on-road and off-road gasoline engines more. That's really the next target."

 The study, led by researchers in Switzerland and Norway with help from Hayes and colleagues in Italy, France and the U.S., looked at carbonaceous particulate matter (PM) emitted from the tailpipes of cars.

Carbonaceous PM is made up of black carbon, primary organic aerosol (POA) and, especially, secondary organic aerosol (SOA), which is known to contain harmful reactive oxygen species and can damage lung tissue.
Particle filters required on

In recent years, newer diesel cars in Europe and North America have been required to be equipped with diesel particle filters (DPFs), which significantly cut down on the pollution they emit.

In the lab (at the Paul Scherrer Institute, near Zurich in Switzerland), "gasoline cars emitted on average 10 times more carbonaceous PM at 22°C and 62 times more at -7°C compared to diesel cars," the researchers noted in their study.

"The increase in emissions at lower temperatures is related to a more pronounced cold-start effect," when a engine is less efficient because it's not yet warned up and its catalytic converter is not yet on, the study noted.

It added: "These results challenge the existing paradigm that diesel cars are associated, in general, with far higher PM emission rates, reflecting the effectiveness" of engine add-ons like DPFs to stem pollution.

That said, it is true that older diesel cars do pollute more than , because they don't have DPFs, and in general emit far more nitrogen oxides, which cause smog and acid rain, the study also noted.
The air in traffic-heavy LA ... and in the Arctic

For their investigation, the researchers utilized field work on that Hayes carried out in California in 2010 and published in 2013 when he was a researcher at the University of Colorado working with Jose-Luis Jimenez (also a co-author of the new study).

Over four weeks in a parking lot of the California Institute of Technology, in Pasadena, Hayes analyzed air coming from nearby traffic-heavy Los Angeles, drawn through a tube in the roof of a modified construction trailer.

Now he's doing something similar up in Canada's Far North, "the final resting place of atmospheric pollution," said Hayes, a New Yorker from Albany who has lived in Montreal since 2013.

He's interested in whether the carbonaceous PM up North exacerbates climate change.

Soot that settles on snow makes the snow darker and, warmed by the sun, the snow melts faster, for example. To better understand the origins of PM in the Arctic, for the past two years Hayes has been taking measurements at Eureka, Nunavut on Ellesmere Island.

He plans to publish his findings next year.

Explore further: Carcinogenic soot particles from petrol engines

More information: S. M. Platt et al. Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars, Scientific Reports (2017). DOI: 10.1038/s41598-017-03714-9

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dirk_bruere
4.7 / 5 (6) Jul 14, 2017
Standards and tests mean nothing if manufacturers cheat
antialias_physorg
4.5 / 5 (4) Jul 14, 2017
It may be a bit late to look to the next generation of gas engines. There may not be one. The first automakers are already stopping further development of diesel engines altogether.
http://www.reuter...8N1IJ1AI
It's only a matter of a few years until the same will happen to gasoline engines.
michbaskett
5 / 5 (4) Jul 14, 2017
They only concentrated on heavy particulate matter which is really only a small portion of the total emmittance from diesel engines. They also ignore the eventual scenario when the filters no longer work and engines discharge tremendous amounts of foul pollution mile after mile. The best scenario is to ban diesels outright along with an eventual ban on internal combustion engines.

I can't help but wonder who was actually behind this "study". Forgive me my scepticism, but I smell a rat and it stinks of corporate backing.
luke_w_bradley
4 / 5 (4) Jul 14, 2017
Diesels are superior at so many levels. Safer, longer lived, quick integration with renewables via biodiesel, on and on. A mechanic told me gas engines can tach up more, but with even new pickups having superior 10 speed automatic transmissions, its moot: These trucks can haul mad weight, then get 30 mpg when empty. Of course for cleanness you're dealing with DEF and other addons, but long life makes it worth it.
Future of tansportation is diesel heavy vehicles for long trips and light electric vehicles for around town.
Eikka
3.5 / 5 (2) Jul 14, 2017
The irony is that the ethanol added to gasoline in the name of reducing CO2 emissions and reliance on fossil fuels is also causing gasoline cars to emit acetaldehyde, which is a group-1 carsinogen and a major contributor to human lung cancer.

They also ignore the eventual scenario when the filters no longer work and engines discharge tremendous amounts of foul pollution mile after mile.


The particle filters regenerate by burning the accumulated soot. Diesel exhaust has leftover oxygen in it, so the ECU injects fuel in the exhaust manifold and that increases the filter temperature to the point where the collected particles ignite and burn.

That is also the reason why the same particle filters don't really work on gasoline cars, because gasoline engines don't run lean. There's not enough extra oxygen in the exhaust to burn off the soot, so the filters eventually clog up.
Shootist
3 / 5 (7) Jul 14, 2017
"We cannot drill our way to $2.00 a gallon gasoline." -- Barack Hussein Obama, the Failed.

Gasoline is currently $1.99 gallon.

Have you hugged a fracker today? You should.

Pratyeka
3 / 5 (2) Jul 14, 2017
@Shootist isn't fracking for natural gas well?
Nik_2213
5 / 5 (1) Jul 14, 2017
We paid a premium for a 'gasoline' car because the default diesel was less much efficient and more polluting for short runs starting from cold. Think 'Trolley Dash'. Takes a while for a diesel's soot-burner to get up to working temperature.

And this *before* the ECM scandal...
Eikka
5 / 5 (2) Jul 14, 2017
@Shootist isn't fracking for natural gas well?


It's connected, because the abundance of cheap gas reduces the demand for other petroleum products that it displaces, which then shows up in fuel prices.

Oil is refined to multiple different things, and when the demand for say heating oil diminishes, the producers push it into gasoline and diesel instead by lowering the prices.
Eikka
3.7 / 5 (3) Jul 14, 2017
Takes a while for a diesel's soot-burner to get up to working temperature.


Another irony is, electric cars in cold climates are commonly equipped with fuel burners that provide the cabin heat during winters. When you start a car cold in -15 C weather, it takes 10 minutes at full blast before the interior starts to heat up to the point where breath doesn't freeze on the windows and you no longer need gloves to drive. In bad weather, you need the window heaters at full blast to keep the snow from freezing on the glass - it's a safety requirement.

Trouble is, the heater core of a regular car puts out 4-5 kW, plus the rear window heater wire because the blowers don't reach all the way back, which is enough to actually drive an EV at a good clip, especially in the city. It basically doubles the power consumption and halves the range at low speeds because the EV would have to take all that power from the battery.

So, guess what they use for fuel?
sirdumpalot
Jul 14, 2017
This comment has been removed by a moderator.
Eikka
3 / 5 (2) Jul 14, 2017
Just kill them both for EV.


Sure. You paying?
EmceeSquared
2.3 / 5 (3) Jul 15, 2017
dirk_bruere:
Standards and tests mean nothing if manufacturers cheat


Sounds like the next Trump bribery agenda, making the EPA a clearinghouse for cheaters like Volkswagen instead of catching them.
EmceeSquared
4 / 5 (4) Jul 15, 2017
Shootist:
"We cannot drill our way to $2.00 a gallon gasoline." -- Barack Hussein Obama, the Failed.
Gasoline is currently $1.99 gallon.


Gasoline is currently $2.46 a gallon:
https://www.eia.g...&f=M

It was $2 or less a gallon for the months of December 2008 and April 2016, despite the huge surplus in global oil/gas supply. Driven by the US fracking that Obama oversaw as part of his "all of the above" energy policy. Which is what drove down energy prices that let the US industry and economy recover faster and deeper than any other in the world. After Bush/Cheney, who you voted for *twice*, even after their lying invasion and lost war in Iraq.

IOW, you're nothing but a goddamn liar about everything. Because you're obsessed with one of the most successful presidents in history's middle name. You're a catastrophe.
EmceeSquared
3.5 / 5 (4) Jul 15, 2017
Eikka:
Another irony is, electric cars in cold climates are commonly equipped with fuel burners that provide the cabin heat during winters.


That's not ironic. Electric motors aren't a magic wand; replacing fossil fuels with sustainable alternatives isn't some religion with edicts. EVs are transitioning us from filthy, wasteful machines to efficient, sustainable ones. It's a vast industrial transformation that will of course take decades, even though we're fully underway. They're of course using the best available tech, but only as it becomes available.

75% or more of gasoline energy contents are blown out as heat - driving is a byproduct. Since EV's are not using an extremely wasteful motor, they don't have an easy source of heat for the cabin, and must sacrifice a little efficiency for that. So far, anyway. EVs will probably gain insulation and require very little heating, airtight because no emissions, so the battery will suffice.

This is progress, not a miracle.
EmceeSquared
3 / 5 (2) Jul 15, 2017
Eikka:
Just kill them both for EV.


Sure. You paying?


In NY subsidies now make a new Nissan LEAF cost $11,500. Yes, we're all paying for those subsidies, because they're far cheaper than paying later for climate catastrophe. Hurricane Sandy alone was already $75B.

New Yorkers are smart, especially about investment. A 300 year history as a global capital gives perspective on who pays now vs who pays later, like the benefits of a $24 investment for Manhattan island.
rrrander
3.7 / 5 (3) Jul 15, 2017
Diesel is s---. Even controlled it still emits fly ash which is a known carcinogen and frankly is horrible to breath when you are behind a vehicle that uses it. The most insane thing are morons who buy $100,000 Mercedes and diesel!! Do they really CARE if it gets slightly less mileage?? Plus, diesel are still noisy compared to gasoline cars. Diesel should be restricted to large trucks and heavy equipment, it is NOT needed in cars.
ugosugo
5 / 5 (2) Jul 15, 2017
@ Shootist

It is always hilarious to read the way simpleton's minds work!
antialias_physorg
5 / 5 (3) Jul 15, 2017
Another irony is, electric cars in cold climates are commonly equipped with fuel burners that provide the cabin heat during winters.

Which should tell you something: Fossil fuels are good at emitting heat when burned, but inefficient at providing motion. Using them as fuel to move something is just stupid.
antigoracle
1 / 5 (2) Jul 15, 2017
Another irony is, electric cars in cold climates are commonly equipped with fuel burners that provide the cabin heat during winters.

Which should tell you something: Fossil fuels are good at emitting heat when burned, but inefficient at providing motion. Using them as fuel to move something is just stupid.

Uh huh. That's why most of the electricity generated, to run those EVs, is generated by burning fossil fuels. RIGHT
betterexists
not rated yet Jul 15, 2017
Will Biofuels also Contaminate the Air ? Fossil Fuels are ready to use after refinement. Biofuels too must go through further refinement, I presume!
Freethinker51
3 / 5 (2) Jul 15, 2017
I don't want more diesel vehicles in the USA. I much prefer gasoline hybrids and fully electric. Fully electric is where we are headed as predicted by me almost a decade ago.

Ultra-fine soot is still omitted by diesel engines and that is what makes diesel engines more unhealthy, according to some scientists. I also believe this. One more breakthrough in lithium-based battery technology or some other discovery that makes lithium-based batteries obsolete is all we need to render gasoline engines obsolete. I imagine diesel engines will still be needed for heavy commercial vehicles, but hope that problem will soon be solved. They are the major polluters.
petey53
5 / 5 (3) Jul 15, 2017
The problem is with gasoline direct injection engines, not all gasoline engines. GDI cars emit large numbers of very fine particles but port injection cars do not. Modern diesels with DPFs have low particle counts but still often have excessive NOx. Port injected gasoline hybrids such as the Prius have low particle counts, low NOx and low CO2 emissions. See ADAC ecotests.
xponen
5 / 5 (1) Jul 15, 2017
The fight over particulate emission seems like a losing battle. Of course we could install a filter at exhaust, but these nano-particulate is still emitted. What we are doing is just passing some arbitrary test, but we still emit the darn thing and we can't fix it. What we are fighting is a fundamental properties of combustion engine, The time we spend trying to fix it, we wasted the time to improve the engine, as it add nothing to the engine.

I think, ideally we should avoid combustion engine, these nano-particulate is dangerous to society in term of public health & mental health, as it was implicated with elzheimer This isn't the first time combustion engine is associated with destabilizing society, such is with the correlation between crime waves in 80s with leaded petrol.
Zzzzzzzz
not rated yet Jul 15, 2017
Electric vehicles will displace the fossil fueled vehicles. Other tech (hydrogen, compressed air, sustainable combustible fuel) will displace vehicles where EVs don't make sense. The tipping point is getting close, now that there are several available that are competitive in cost, range, etc....
Laws help, but producing better choices is a far more powerful force.
Freethinker51
not rated yet Jul 15, 2017
I just read the article on direct injection gasoline engines and they are said to omit far more ultra-fine soot particulates than modern diesel engines with filters. We better solve that problem in a hurry if this is true.
EmceeSquared
not rated yet Jul 15, 2017
Freethinker51:
I don't want more diesel vehicles in the USA. I much prefer gasoline hybrids and fully electric. Fully electric is where we are headed as predicted by me almost a decade ago.

Ultra-fine soot is still omitted by diesel engines and that is what makes diesel engines more unhealthy, according to some scientists. I also believe this.


This whole article is about new diesel engines polluting less particulates than even new gasoline engines. You didn't read it.

One more breakthrough in lithium-based battery technology or some other discovery that makes lithium-based batteries obsolete is all we need to render gasoline engines obsolete.


It's going to be a long, hard slog moving from petrofuels to sustainables. Biodiesel is sustainable, uses existing infrastructure including vehicles. They'll help make the necessary smooth transition.
EmceeSquared
not rated yet Jul 15, 2017
antigoracle:
That's why most of the electricity generated, to run those EVs, is generated by burning fossil fuels. RIGHT


Yes, but the grid is becoming more efficient a lot faster too. That is one reason EVs are more sustainable: electricity production can be made sustainable quickly for lots of people at once.

Despite the trolling from you and your ilk that does nothing but keep energy filthy.
EmceeSquared
not rated yet Jul 15, 2017
Freethinker51:
I just read the article on direct injection gasoline engines and they are said to omit far more ultra-fine soot particulates than modern diesel engines with filters. We better solve that problem in a hurry if this is true.


This article is all about how new diesel engines with filters emit far less nanoparticles. Which could be an important part of solving that problem. Why didn't you read it?
rrrander
not rated yet Jul 16, 2017
Filters are ridiculous. Diesel emits huge amounts of solid particles. Effective filters would clog fast and cost a lot to keep replacing. They need some kind of scrubbing system which would cost a fair amount to develop and fit, but at least it wouldn't rely on filtration that would need to be constantly replaced.
Eikka
not rated yet Jul 16, 2017
replacing fossil fuels with sustainable alternatives isn't some religion


In NY subsidies now make a new Nissan LEAF cost $11,500. Yes, we're all paying for those subsidies, because they're far cheaper than paying later for climate catastrophe.


It sure seems like a religion, complete with dogmas and blind faith in performing pointless rituals, because those subsidized electric cars right now don't do anything to reduce any greenhouse gasses - so the money we're all forced to pay for them is essentially wasted.

You need to clean up the grid first before electric cars make sense. Otherwise the higher cost is causing more harm. Right solutions at the wrong time are wrong solutions.

Remember that higher cost in money always means higher cost in other resources, because somebody's got to earn that money, and so people have to consume more stuff to be able to work more, and so more greenhouse gasses are generated.
Eikka
1 / 5 (2) Jul 16, 2017
Ultimately the EV is going to be a side track, because of the difficulties with batteries, their properties and their manufacturing in the massive massive volumes required.

1) renewable energy needs to be stored and stockpiled for later use in extremely large amounts
2) the most convenient way to store large amounts of energy we know of is hydrocarbons (gas/oil)
3) methods exist to turn renewable energy into liquid hydrocarbons for storage
4) it would be pointless to turn fuel to electricity to charge an EV when you can use it directy in a car.

Transportation is a minor part of the energy demand of a society. Once the society's energy needs are met with renewables, there will be enough synthetic gasoline, ethanol, diesel, butanol etc. whatever you want to run ordinary cars and fuel cells, stirling engines, what have you.

The combustion engine just isn't going away. The battery electric car is, the same way it did a hundred years ago: being outmoded by better rivals.
Eikka
1 / 5 (2) Jul 16, 2017
The question is rather about how to make them clean. Continuously burning engines like stirlings or microturbines, or SOFCs produce very little to absolutely no NOx or particulate matter at all. Just water and CO2.

Electric cars are fine though. Electric traction is just a different transmission - the actual power source can be anything - the point is that batteries are a huge liability, a huge waste of resources and will not stand the test of time.

Effective filters would clog fast and cost a lot to keep replacing. They need some kind of scrubbing system


Again, effective particle filters exist, and they automatically regenerate by glowing red hot until the soot particles burn off into CO2.
EmceeSquared
5 / 5 (2) Jul 16, 2017
Eikka:
It sure seems like a religion, complete with dogmas and blind faith in performing pointless rituals, because those subsidized electric cars right now don't do anything to reduce any greenhouse gasses - so the money we're all forced to pay for them is essentially wasted.

You need to clean up the grid first before electric cars make sense.


It's really disappointing that you keep posting pretending that converting the world's transit infrastructure from petrofuels to a sustainable energy system doesn't require vast, complex investments over many years by billions of people around the world. Ignoring the gains already achieved in grid GHG efficiency. The cheapness of subsidies to transform technology and markets, averting vaster (even existential) costs later.

You're smart and informed, Eikka. You've been shown these arguments plenty of times, and can't rebut them. Give up your religion crusading against EVs and be part of the solution instead of the problem.
IronhorseA
5 / 5 (1) Jul 16, 2017
"
You're smart and informed, Eikka. You've been shown these arguments plenty of times, and can't rebut them. Give up your religion crusading against EVs and be part of the solution instead of the problem."

I think at heart, you're hearing the argument of someone who wants 1970's level acceleration. You can't get that in efficient cars which is why alot of people switched to pickups and SUV's, they were the big hole in the gas mileage legislation of the '70's because few people drove them back then. Every argument against efficient transportation starts with a Nascar/Formula 1 driving mentality. ;P
greenonions1
not rated yet Jul 16, 2017
You need to clean up the grid first before electric cars make sense.
It can be done simultaneously. Tesla is converting most of their charging stations over to solar. - https://electrek....on-musk/ Another thought - burning 1 gallon of gasoline - gives of about 20 pounds of C02 - https://www.eia.g...amp;t=11 So if you have a small car that gets 30 mpg - you will be producing about .66 pounds of C02 per mile. An electric car gets about 3 miles per Kwh. One Kwh of electricity will generate an average of about 1.1 pounds of C02 - https://www.sunea...ator.php - or about .36 pounds per mile. If your energy source is predominantly nuclear, or hydro - you are WAY ahead of the game to drive an EV. The more coal you get in the mix - the closer you get to parity - but we are closing coal plants - and transitioning to renewbles. No brainer.
Dark_Solar
not rated yet Jul 16, 2017
Filters are ridiculous. Diesel emits huge amounts of solid particles. Effective filters would clog fast and cost a lot to keep replacing.


Maybe as a non-filter scrubbing system use a post-burn, air-injected turbine assembly to burn those particles and capture otherwise lost energy? For that matter, why not do the same with gasoline engines? All that exhaust has immense potential for further use; rather than running it though a catalytic converter and generating wasted heat, burn it again in a turbine....or maybe slap a Peltier generator on the catalytic converter and dump that energy into an assist motor or back into the battery.
EmceeSquared
5 / 5 (1) Jul 16, 2017
IronhorseA:
I think at heart, you're hearing the argument of someone who wants 1970's level acceleration.


I dunno, EVs accelerate faster than equivalent ICEs. I think it's mainly a macho "who are you to tell me I can't waste whatever I want?" attitude. Plus the entitlement of running up the costs externalized to the fuel burner, spread across everyone for the burner's benefit. And all that has been the immersive advertising by vehicle/energy and other consumer corporate webs for generations.

It's cultural, not engineering or economic. It's wrong, but it's the QE2 that must be turned.
EmceeSquared
5 / 5 (1) Jul 16, 2017
EmceeSquared:
Eikka:
It sure seems like a religion, complete with dogmas and blind faith in performing pointless rituals, because those subsidized electric cars right now don't do anything to reduce any greenhouse gasses - so the money we're all forced to pay for them is essentially wasted.

You need to clean up the grid first before electric cars make sense.


[...]the gains already achieved in grid GHG efficiency.


The US electricity grid 2010-2016 cut almost 11% of its GHGs, cut almost 10% of its GHG:W emissions rate, and (most amazingly) cut over 27% of its GHG:GDP emissions rate, as GDP itself grew over 27%. Wow!

2010 Grid GHG emissions:
https://www.epa.g...bles.pdf

So even if EVs themselves are breakeven GHGs (greater efficient at "site" == lesser efficiency at "source"), the grid's 10% cut in GHG:W makes EVs already cut 10% GHGs from the ICEs they replace.
antialias_physorg
5 / 5 (2) Jul 17, 2017
All that exhaust has immense potential for further use; rather than running it though a catalytic converter and generating wasted heat, burn it again in a turbine....or maybe slap a Peltier generator on the catalytic converter and dump that energy into an assist motor or back into the battery.

As always: These solutions are complicated (read: service-intensive), and expensive...not to mention ineffective. E.g. the efficiency of something like a (expensive!) Peltier element is very low. Notice how car manufacturers are already turning off all these post-motor systems to fudge their MPG values.

...and not just VW in dieselgate. ALL manufacturers do this in "motor protection" modes - which are active whenever your car is cold. I.e. for most drivers this means most of the time for their daily commute/shopping trip. Fudging this via 'motor protection' modes is completely legal, BTW.
Shakescene21
5 / 5 (1) Jul 17, 2017
Diesel manufacturers have lied to us so criminally that I won't ever consider buying a diesel car again. (At least not for decades.) There are many millions of consumers like me across the globe, and the auto companies know it.

I think the auto companies will downplay diesel-engined cars for the next decade or longer, and by then technological advances in batteries, fuel cells, and/or capacitors will make diesel cars uncompetitive in most markets.

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