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European automakers and fuel suppliers argue for diesel as they call on policy makers to accelerate fleet renewal

In an open letter to EU policy makers, leading representatives of the automotive and petroleum refining industry in Europe called on policy makers to help accelerate fleet renewal and the introduction of the cleanest vehicles and committed to keep pushing the technical boundaries in order to find ever better ways of combining the customer benefits of diesel—fuel economy and low CO2—with continuously reduced emissions.

The associations pointed out that political measures restricting the rollout of the new generation of diesel technology would undermine existing efforts to cut CO2 emissions.

The letter from the Presidents of the European Automobile Manufacturers’ Association (ACEA, currently headed by Carlos Ghosn); the Association for Emissions Control by Catalyst (AECC); the European Association of Automotive Suppliers (CLEPA); and FuelsEurope, representing the European Petroleum Refining Industry, was sent to representatives of the European Commission, European Parliament and Council.

European vehicle manufacturers and their suppliers, in cooperation with the refining industry, lead the world in the development of state‐of‐the‐art diesel engine technology. We have introduced high‐efficiency diesel engines and diesel particulate filters that eliminate almost all particle emissions from the exhaust tailpipe. The very latest generation of diesel technology combines clean diesel fuel, advanced engines and effective emissions control mechanisms.

… Since 1992, the EU has introduced increasingly stricter limits on vehicle emissions through a series of ‘Euro’ standards, and the industry has played its part by demonstrating technical feasibility as a basis for those standards. The latest and most stringent of these standards is Euro 6. New car types already comply with Euro 6, and from 1 September 2015 all new cars sold will have to meet this standard. Criticisms that Euro 5 cars fail to deliver real‐world improvements compared to the laboratory test cycle conditions are also being addressed. Euro 6 will require real‐world emissions testing of cars for the first time. The automotive industry is actively supporting these developments.

Technical innovation has helped progressively to lower vehicle emissions—over the last 15 years, NOx limits for diesel engines have been reduced by 84%, and particulates by 90%. Diesel cars, having significantly lower CO2 emissions per kilometer, are essential to manufacturers’ efforts to reach the EU’s 2021 CO2 fleet average targets and thereby help reduce road transport CO2 emissions and mitigate climate change. With continuing efficiency improvement, diesel will continue to be essential in meeting post‐2021 targets.

Political measures restricting the rollout of the new generation of diesel technology would therefore undermine existing efforts to cut CO2 emissions. Such measures make no sense from an environmental point of view.

—from the joint letter

ACEA’s members are BMW Group, DAF Trucks, Daimler, Fiat Chrysler Automobiles, Ford of Europe, Hyundai Motor Europe, Iveco, Jaguar Land Rover, Opel Group, PSA Peugeot Citroën, Renault Group, Toyota Motor Europe, Volkswagen Group, Volvo Cars, Volvo Group.

AECC is an international non-profit scientific association of European companies making technologies for engine exhaust emissions control. The members of AECC are companies operating worldwide in the research, development, testing and manufacture of key technologies for emissions control.

CLEPA is the European Association of Automotive Suppliers. 113 of the world’s most prominent suppliers for car parts, systems and modules and 24 national trade associations and European sector associations are members of CLEPA, representing more than 3,000 companies, employing more than 5 million people and covering all products and services within the automotive supply chain. Based in Brussels, CLEPA is recognised as the natural discussion partner by the European Institutions, United Nations and fellow associations (ACEA, JAMA, MEMA, etc).

FuelsEurope’s 42 members account for almost 100% of petroleum fuels refining and more than 75% of motor fuel retail sales in Europe.



The joint letter essentially says in the same breath
•that emissions figures are excellent <> all these figures come from "Improved Prepared Vehicles" for Homologation Tests
•and that these figures are not to be trusted <>
•a good-faith person can google and find at least two or three press articles about how Nox figures in reality have not been cut down

Besides, you can see that ACEA, AECC, CLEPA, and FuelsEurope are all Big Business, certainly as much anxious to counter any new regulation, as they are anxious to help us improve our health.

In old-time three-way-catalyzed indirect-injection gasoline engines, we used to have very low and *real* Nox figures and Particulate figures.
•the three-way catalyst was quite simple and un-expensive by today's highly-complex multiple-sensor cars (more like computer with wheels, than cars)

Now, obsessed with CO2, we introduced complex contraptions that make it ever harder to fight emissions :
•for example, direct-injection gasoline spew out now more Nox and Particulates *on the paper* than diesel engines
•this sad state of affairs is allowed, until Euro 6b kicks in
•diesel engines spew out on the paper less Nox and Particulates, in real-life we still don't know
•our planet may slow down CO2 output, at the cost of greatly increasing deadly Nox and Particulates
•meanwhile, Big Business passes on us end-users and buyers of their devices, the brunt of the costs of this increasing complexity

Isn't the best path, simply
•to emphasize catalyzed indirect-injection gasoline for all passenger cars
•to have diesel only on trucks, and public transportation, with tight real-world-emissions-control

To summarize
•relax regulation on CO2 but tighten it on Nox and Particulates
•emphasize simplicity : more biking, more walking

Of course this goes against the grain of "making you dream by selling you a car"


On any warm summer day, in a large city in France (a highly diesel-friendly country) such as Rennes, Nantes, if you're a cyclist caught in snail-pace traffic, you can breathe the pungent smell of ***clean-diesel*** exhausts (I really mean diesel manufactured after 2010, as you can see by their makes & models). Your lungs and mucous membrane really can feel the pain of processing this alien mixture of air, soot and Nox poisons. Car-drivers, don't just believe me : give this a try, leave your cars at home, bring out your bikes and go touring our cities on any work-day. This is real-world emissions.


I hope diesels will be banned completely here in Europe as soon as possible. France is already considering it and the more research goes into it, the more obvious it becomes that they are a serious threat to public health everywhere in higher concentrations (cities).

I cycle a lot and agree with the Allweatherbiker that diesels are the worst offenders in terms of destroying breathable air. Often a couple of years old, "modern" diesels release a lot of soot and even the ones with invisible exhaust have a chocking effect if one gets a puff. Normal gas cars at least don't have this effect.

Massive electrification is the way to go for livable cities. Diesel is a dead end and we should get rid of it as soon as we are able to.


I am on my second clean diesel car (2015 model year; first one was a 2010), and there has never been any detectable odor from either vehicle, whether cold-started, hot-started, or otherwise run in a small enclosed garage. There are no irritating fumes, even directly from the exhaust pipe, only hot air perceptibly coming from the exhaust pipe.

Using smell as a way to evaluate the toxicity of fumes isn't valid anyway. Many extremely unpleasant smelling agents are harmless, while many extremely toxic agents are either odorless or have a pleasant odor.

Diesel exhaust from current-technology diesel engines has been shown to be benign...

If Europe has a problem with diesel exhaust, it's from pre-Euro 5 vehicles. Banning new diesel vehicles would serve no purpose.


It may be the obvious comment, but I suppose your excrement doesn't smell either. Why should we believe that your personal assessment of the fumes from your diesel car exhaust is any more reliable. If it is so benign, I suggest you route the exhaust into your HVAC system instead of releasing it for others to endure.Those of us who hate having to breathe that, regardless of your opinion as to validity, surely have a right to expect that it be ended ?And hope the politicians are not swayed by this bunch of Big businesses pushing their barrow.Shame on Carlos Ghosn, whose organisation also gives us a number of good EVs.



So any assessment of diesel exhaust with which you don't agree you simply dismiss?

Show me where the ACES study (referenced in the greencarcongress link) is funded by "Big Business pushing their borrow". Do you consider the U.S. Environmental Protection Agency to be "Big Business"?


Carl, I suggest that that view of diesel exhaust may apply equally to you, by your irrational defence of it. My objection may not be based upon any study which you recognise, but is, like other posters above, based upon my intense dislike of the fumes which always come with even the latest models. We should not have to put up with that, no matter how much you and other diesel defenders are saving in fuel costs, the real reason, I know, from acquaintances, for supporting its use. You may dismiss subjectivity, but I maintain that those of us whose olfactory systems are still working properly do have a right not to be offended in that way.Not everything in this world has to be justified by the kind of reported studies you want to see as evidence of its truth.And I do not believe that the EPA is an offshoot of big business either, only that certain sections of the US Congress would like to see it abolished, thanks to their connections with big business. The EPA is possibly one of the better creations of US governments of the past fifty or so years from what I can see, looking on from abroad. I do weary of people who will accept nothing which is not supported by some study which can be referenced, always demanding "Evidence".This is not a court of Law, and if I want to dismiss any assessment of exhaust which I don't like then I shall, especially as a European study reported here not many months ago found that in the real world, Emissions were in fact exceeding the standards supposedly being claimed by OEMs for Type Approval. And now, because I cannot recall the reference, you will I suppose dismiss that as an invention of mine.



I am aware of the European study you reference - Vicente Franco, et al., “Real-World Exhaust Emissions From Modern Diesel Cars.” ICCT. That study measured real-world NOx emissions that were generally higher than the regulatory limit, but it also reported other emissions that were orders-of-magnitude lower than the regulatory limits. PM was nearly 100% below the regulatory limit (i.e., near zero). There's also another study that shows NOx emissions from 2010-compliant diesel trucks in the real world have been reduced by 98% (

My sympathies that your sense of smell is so acute that you can smell non-existent odors. My olfactory senses are just fine; I can smell pre-2007 diesel vehicle exhaust from a considerable distance.

The fact remains that a rigorous study has found that exhaust from current-technology diesels has no public health impacts. If you'd bother to read the full report, it says that the exhaust was so concentrated that a cooler had to be installed to keep the temperature in the exposure chambers tolerable (page xvii of "Preface"). Yet the exposed subjects had no health effects over their normal lifespan that were significantly different from the control group which was exposed exclusively to HEPA-filtered room air.

Also, this was exhaust from a 2007-compliant diesel truck engine; 2010-compliant diesel truck engines are significantly cleaner still (, and have the same emission control technologies as virtually all of the diesel cars, SUVs, and pickup trucks on the U.S./Canadian market today (SCR & DPF).

Furthermore, the steering committee for these ACES studies consisted of representatives from not only government agencies (EPA, DOE, CARB), but also environmental activists groups (National Resources Defense Council). Your "big business" conspiracy theory is what is irrational.


I did read that 12/013 study showing that Lab. rats survived breathing truck diesel exhaust, but that was just rats, renowned survivors of unhealthy conditions such as sewers, rubbish tips etc. And if you think that lower Pm concentrations can justify higher than permitted NOX levels, think again, because NOX is what causes that horrible choking effect experienced by our bicycling friends above. You may claim that I am smelling "non-existent odours" but that is just your clearly prejudiced opinion. Arguing about what you or I can or cannot smell is a pointless exercise, unprovable either way. I shall continue to assert that neither I nor anybody else should have to breathe what I am aware of every time I have to follow even a latest model diesel vehicle on the road, and if you want to believe it holds no health hazards, then you breathe it.But please do not come here attempting to justify your use of it by claiming you cannot smell it, even in your garage.I and no doubt many others can do so, and dislike it intensely.
Lastly, in referring to the signatories to the open letter which was the subject of the original report here, as 'Big Business', I was being quite factual, with no suggestion of any Conspiracy theory. They were, in pressing such views, clearly, simply "pushing their Barrows", a saying which I suggest you familiarise yourself with, to understand its meaning, and spelling.



Rats have been used routinely in inhalation studies. LC50 levels have been established based on lab rat survival rates at various concentrations of subject gases/vapors. NO2 (a component of NOx; NOx = NO + NO2) was the limiting factor in the ACES diesel exhaust study. The 4.2 ppm NO2 limit in the "high exposure" chamber is almost 100 times the ambient air quality standard limits for NO2 (0.053 ppm in the U.S.)

Even if real-world NOx emission rates from late-model diesels are as high as the one study you cite suggests, it's still less than half what the U.S. EPA says 1990s-era petrol cars emitted (~2 grams/mile). Even then, all areas in the U.S. meet the NO2 National Ambient Air Quality Standards (NAAQS) and have since 1998. And there's still the study that shows that real-world NOx emissions from diesel trucks have been reduced by 98%.

In fact, I breath diesel exhaust regularly, not only from my own diesel car in an enclosed garage, but following diesel cars and trucks on the highway. New diesel pickup trucks can easily be identified from behind; the tailpipes are large and ventilated. The large OTR trucks have DEF tanks clearly visible. I never smell any odor coming from the post-2007 diesels, yet I can clearly smell the exhaust of pre-2007 diesel trucks and buses. I can smell the exhaust of diesel farm tractors from as much as 1 km away if the wind direction is right.

Europe effectively required filters (DPF) on diesels after September 2011 (Euro 5b). I suspect the commenters here are misidentifying pre-2012 diesel car models for post-2012 models.


You simply refuse to get it don't you. It doesn't matter how many studies you quote, I am a human not a Lab. Rat, and there is nothing you can say which will convince me that I should put up with the annoyance of having to breathe the foul smelling exhaust pumped out by you and, no doubt, others just like you in the region where I live as you drive along in your precious diesels. More, I am quite capable of identifying late models from their plates, so that argument fails. Further, You are not me, so it is absolutely impossible for you to be able to claim that you know what I can or cannot smell, and your continued arrogant and stupid insistence upon being able to is most enraging. You do of course have the freedom to believe there to be no health hazards in breathing current model diesel exhaust, and long may you continue to do that safely, but I look forward to the day when regulatory bodies around the world feel the need to raise the standard to a level which forces every last one of these vehicles off the roads.I don't forsee it happening in my lifetime, but I at least may shuffle off with a smile of anticipation on my face.

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