Dirty diesels: most polluting cars revealed

Dirty diesels: most polluting cars revealed

Dirty diesels: most polluting cars revealedDiesel emissions testing carried out by Which? has revealed the worst diesel cars for air pollution. The figures highlight a huge variation across the industry, with the worst offenders emitting up to nine times the level of dangerous pollutants permitted in official tests. Read on to discover more about the dirtiest diesels and how Which? conducted the tests.

There are emission laws in place to limit the amount of NOx produced by cars, but Which? has uncovered huge differences in the amount of NOx emissions produced by diesel cars from different brands. Crucially, Which? uses real-world tests, replicating the way drivers really drive their cars.

Which? has provided the averages for diesel cars tested between 2012 and 2016, with the results based on data for Euro 5 compliant cars, rather than the stricter Euro 6 emission limit. The results are presented in reverse order, with Euro 6 information included where applicable.

21. Mitsubishi: 0.31 NOx g/kmDirty diesels: most polluting cars revealed

The Euro 5 diesel limit is 0.18g/km of NOx, which means even the cleanest car on the list fails to meet the target. The Which? data is more accurate as the tests use more realistic cycles, including motorway testing, where the car is accelerated to and then sustains motorway speeds.

20. SEAT: 0.32 NOx g/kmDirty diesels: most polluting cars revealed

Of the figures, Richard Headland, Which? magazine editor, said: “While our tests show that some car manufacturers are making progress on reducing the amount of toxic emissions from their models, many have a long way to go in cleaning up their act.”

SEAT, Euro 6: 0.11 NOx g/km.

19. Audi: 0.33 NOx g/kmDirty diesels: most polluting cars revealed

Headland continued: “We hope that the improved official tests brought in later this year will more clearly name and shame those manufacturers that are failing to meet their obligation to lower emissions.”

Audi, Euro 6: 0.15 NOx g/km.

18. Skoda: 0.33 NOx g/kmDirty diesels: most polluting cars revealed

The improvements mentioned by Richard Headland refer to the World Harmonised Light Vehicle Test Procedure (WLTP), which replaces the much-criticised New European Drive Cycle (NEDC). In a nutshell, WLTP will introduce stricter controls and cycles to reflect normal driving behaviour.

Skoda, Euro 6: 0.14 NOx g/km.

17. Volkswagen: 0.34 NOx g/kmDirty diesels: most polluting cars revealed

Perhaps unsurprisingly, the NOx figures for SEAT, Audi, Skoda and Volkswagen are within 0.2g/km of each other. As Which? points out, the Euro 5 diesel cars tested are part of the ongoing VW emissions investigation, so a question mark remains over the results.

Volkswagen, Euro 6: 0.11 NOx g/km.

16. Volvo: 0.40 NOx g/kmDirty diesels: most polluting cars revealed

Which? says it recorded a (comparatively) low NOx average across the seven Euro 5 Volvos it tested, but the four Euro 6 Volvo cars actually emit more NOx than the Euro 5 vehicles.

Volvo, Euro 6: 0.43 NOx g/km.

15. Toyota 0.40 NOx g/kmDirty diesels: most polluting cars revealed

Toyota performed well, with the Euro 6 figure even lower at 0.13g/km. However, this is still higher than the 0.08g/km European limit for Euro 6 vehicles.

Toyota, Euro 6: 0.13 NOx g/km.

14. BMW: 0.41 NOx g/kmDirty diesels: most polluting cars revealed

Which? is quick to praise BMW and MINI, saying that the 33 cars tested produced some of the lowest NOx averages for diesel cars. While MINI doesn’t feature in the Euro 5 results, it did produce the best result for Euro 6 compliant cars. A figure of 0.08g/km means it just meets the European target.

BMW, Euro 6: 0.14 NOx g/km.

13. Honda: 0.45 NOx g/mDirty diesels: most polluting cars revealed

To produce the figures, Which? analysed 278 diesel cars from leading manufacturers between 2012 and 2016. Five Honda vehicles were tested, producing a result of 0.45 NOx g/km.

12. Vauxhall: 0.46 NOx g/kmDirty diesels: most polluting cars revealed

Other brands for which only Euro 6 compliant cars are tested include Dacia (0.59g/km), DS Automobiles (0.26g/km), Mazda (0.21g/km) and Jaguar (0.18g/km). Meanwhile, in the Euro 5 table, Vauxhall achieves a figure of 0.46g/km.

Vauxhall, Euro 6: 0.25 NOx g/km.


11. Fiat 0.48 NOx g/kmDirty diesels: most polluting cars revealed

Meanwhile, four Fiats were tested, with a result of 0.48 NOx g/km.

10. Mercedes-Benz: 0.48 NOx g/kmDirty diesels: most polluting cars revealed

A total of 17 Mercedes-Benz cars were tested (7 Euro 5 and 17 Euro 6), with a Euro 5 result of 0.48g/km.

Mercedes-Benz, Euro 6: 0.15 NOx g/km.

9. Peugeot: 0.52 NOx g/kmDirty diesels: most polluting cars revealed

Peugeot finishes 9th in the Euro 5 table, making it the best performing French brand on the list. Its Euro 6 performance is one of the best recorded by Which?.

Peugeot, Euro 6: 0.11 NOx g/km.

8. Kia: 0.53 NOx g/kmDirty diesels: most polluting cars revealed

Kia finishes eighth, with a NOx figure of 0.53g/km.

Kia, Euro 6: 0.29 NOx g/km.

7. Citroen: 0.56 NOx g/kmDirty diesels: most polluting cars revealed

Slightly behind Kia we find Citroen, with a NOx figure of 0.56g/km.

Citroen, Euro 6: NOx 0.16g/km.

6. Ford: 0.58 NOx g/kmDirty diesels: most polluting cars revealed

There’s not a huge amount of difference between Ford’s Euro 5 and Euro 6 figure, with the more lax Euro 5 test revealing an output of 0.58g/km.

Ford, Euro 6: 0.49 NOx g/km.

5. Hyundai: 0.60 NOx g/kmDirty diesels: most polluting cars revealed

Hyundai is committed to delivering 14 or more new environmentally-focused models by 2020, which should go some way to improving this top five finish.

Hyundai, Euro 6: 0.40 NOx g/km.

4. Renault: 0.73 NOx g/kmDirty diesels: most polluting cars revealed

NOx emissions from the 16 Renault diesel cars tested are seven times higher than the Euro 6 MINIs tested. In response, Renault said: “Since mid-2015, Groupe Renault has committed to improve the performance of its anti-pollution systems. The vehicles tested by Which? would not have benefitted from this improvement plan”.

Renault, Euro 6: 0.72 NOx g/km.

3. Land Rover: 0.78 NOx g/kmDirty diesels: most polluting cars revealed

In third place is Land Rover, which was one of six manufacturers for which the consumer group only has average figures for Euro 5 compliant cars.

2. Nissan: 0.81 NOx g/kmDirty diesels: most polluting cars revealed

In response to the results, Nissan said: “We are committed to upholding the law and meeting regulations in every market where we operate. Specifically in Europe, all our vehicles sold in Europe meet the Euro 5/6 emission standards. This report, which looks at the variation between lab and ‘real world’ conditions, shows significant variances for most brands tested”.

1. Jeep: 1.74 NOx g/kmDirty diesels: most polluting cars revealed

That leaves Jeep to secure the unwanted position at the top of the dirty diesels tree. Jeep failed to provide a response to the research.

Emissions testing

German carmakers ordered to recall cars for emissions fix

Emissions testingThe German government has instructed Daimler, Opel and Volkswagen Group to recall 630,000 cars so emissions systems can be adjusted to remove temperature-dependant devices, according to reports in Bild newspaper.

German government engineers have been probing car manufacturers since the Volkswagen defeat device emissions crisis emerged in September. 56 models have been tested.

The device in question here is a system that only engages the particulate filter at certain temperatures. Daimler is one car maker that’s admitted such a device is fitted – insisting it’s a perfectly legal system designed to protect the engine when cold.

They may be legal, Stefan Bratzel from the Centre of Automotive Management at Germany’s University of Applied Sciences said, but they’re not legitimate. It “shines a negative light on the industry as a whole,” he told Bloomberg. “This isn’t a good sign.”

The NEDC fuel economy and emissions test cycle is conducted from a cold start, meaning the system would be active for at least part of it while the engine warmed up.

Experts did, however, stress that the only unquestionably illegal ‘defeat device’ found to date is that on Volkswagen diesel cars. This system could sense when the engine was being put through an official test cycle and emissions controls were adjusted to help it pass strict NOx limits without expensive aftertreatment tech.

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Volkswagen to reveal how it will fix U.S emissions-cheat diesel cars

Volkswagen badgeVolkswagen will today reveal how it plans to fix almost 600,000 U.S diesel cars fitted with emissions-cheat ‘defeat device’ software – and has reportedly set aside $10 billion to resolve civil claims and lawsuits.

Some are predicting Volkswagen could even take the unprecedented step of offering to buy back affected cars, rather than fix them through dealers. AP News has also said Volkswagen will spend $1 billion compensating owners of affected diesel cars.

Volkswagen chief Matthias Mueller has already admitted the €6.7 billion Volkswagen set aside to cover the emissions scandal was not enough.

In March, a U.S district judge Gave Volkswagen until 21 April to reveal details of how it plans to resolve the ‘dieselgate’ emissions scandal. This involved diesel cars with software that detected when the cars were taking part in an emissions test and altered engine settings to cut NOx emissions.

In real-world use, the software reverted back to normal – and some models could emit 40 times the legal limit for NOx emissions.

Volkswagen has reportedly been in advanced discussions with U.S environmental regulators to find a solution to the emissions scandal. Today’s deadline means news of a settlement is expected soon – and in anticipation of positive news, Volkswagen shares actually rose 7% in early trading in Frankfurt.

Ahead of today’s expected announcement, Volkswagen, the Environmental Protection Agency (EPA) and U.S Justice Department have all declined to comment to news agencies.

More news as we get it…

MPs call for Low Emission Zones in cities

EU agrees to cut real-world car emissions – but green groups are not happy

MPs call for Low Emission Zones in citiesThe European Parliament has voted not to block the introduction of Real Driving Emissions testing from 2017, meaning that new cars will be tested for emissions such as NOx in real life conditions, not in regulated labs.

And who was trying to block this apparent good move for air quality? Not the car makers, but MEPs – because they think the exemptions car makers have been granted are too generous.


In 2007, it was agreed that European regulations would demand cars emit no more than 80mg/km of NOx under the Euro 6 limit currently in force.

Vehicles are homologated in laboratory conditions to prove that they meet this limit, as part of the NEDC fuel consumption test.

However, on-road testing has found that many vehicles exceed this NOx limit in real world use, sometimes by 4-500% or more. The Real Driving Emissions test – RDE – has been under development for several years to try and overcome this.

And then came dieselgate

The Volkswagen emissions scandal accelerated its rollout: it was agreed in October 2015 that it would come into force from 2017 – first for all newly-introduced models, and then for all new cars sold.

There’s a ‘but’, though. Because car makers were basing their developments on the existing lab test – which critics argue is easier to fool (indeed, this is exactly what Volkswagen’s ‘dieselgate’ cheat was based upon) – they sought an exemption that would relax the limits for a couple of years.

They won one.

In September 2017, new models to market would be allowed to emit up to 2.1 times (110%) the 80mg/km limit, which would extend to all cars on sale by September 2019.

This discrepancy would be reduced to 1.5 times (50%) by January 2020 for new models, and by January 2021 for all cars sold. This leniency would remain in place going forward – to account for margins of error in the testing kit (called Portable Emissions Measurement Systems, or PEMS).

A date when the variance from the norm will become zero – meaning vehicles would have to emit the 80mg/km limit set back in 2007 – has not yet been agreed.

‘Good day for dirty deals’?

Still with us? Good – because today’s vote was one of the final hurdles against the introduction of this. MEPs were trying to block the introduction of RDE because they argue these exemptions are too kind on car makers – particularly the 50% margin of error. They say the actual margin of error is more like 20%.

“Today was a good day for dirty deals but a bad day for cleaner air,” said Liberal Democrat MEP Catherine Bearder.

However, the RAC’s Steve Gooding said the vote was “a step in the right direction” as it would cut NOx from today’s spiralling emissions to two times the limit, and then 1.5 times – without delay.

A rejection of the decision already made by EU member states “would delay improvements to air quality, particularly in cities,” said European automotive industry body the ACEA.

The car makers say…

RDE will introduce a completely new testing method for vehicles on the road. Europe is the first and only region in the world to introduce such a system, which will lead to major progress in improving air quality.

While the current proposal takes into account error margins in the new measuring equipment, vehicle manufacturers will have to aim well below the legal limit to ensure compliance. Moreover, the error margin will be reviewed and, as the equipment improves in precision, the conformity factor will be tightened.


The environmental campaigners say…

The European Parliament today caved in to pressure from car-producing countries and agreed to weaken the limits for nitrogen oxide (NOx) emissions from new diesel cars. The effective new ‘Euro 6’ limit, 168mg of NOx per km, is more than double that agreed in 2007 (80mg/km). From 2020, all new cars will still be allowed to emit 120mg/km.

Despite public outcry, EU governments have pressured national MEPs to accept the weakening of the legal limits that was agreed via the backdoor of comitology in October of last year. The decision will undermine efforts to clean up Europe’s air and improve public health.

– Transport & Environment

What do you think of today’s vote? Share your thoughts of which side you’re on below…

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Volkswagen ‘among worst performing brands’

Classic Volkswagn badgeThe Volkswagen emissions scandal has caused the firm’s brand value to plunge by even more than experts initially estimated – which has led to big falls in its overall brand power.

Brand valuation firm Brand Finance has revealed its latest Global 500 rankings for 2016, and its analysis has revealed Volkswagen to be one of the very worst performing brands of the year.

It has fell down the rankings from 17th to 56th, due to a staggering $12 billion decline in the power of its brand. This is even more than the $10 billion cost initially estimated by Brand Finance.

It leaves the Volkswagen brand worth $18.9 billion, instead of the near-$31 billion it was valued at this time last year.

Volkswagen’s fortunes “come as little surprise given the scale of the scandal that has engulfed the brand,” said Brand Finance, “following revelations that it programmed its diesel vehicles to activate their optimal emission-reduction settings only when being tested.

The damming result is that, “under normal conditions, they would emit up to 40 times the more nitrogen oxide” and the effect on Volkswagen’s brand value has been stark.

Brand Finance’s analysis is based on factors such as familiarity, loyalty, promotion, marketing investment, staff satisfaction and corporate reputation. The battering the latter’s taken for Volkswagen has been enormous and it’s only by turning it back around will the value of the brand recover.

Filling station pumps

2017 real-world emissions mpg test approved by EU

Filling station pumpsThe European Commission has approved a new Real Driving Emission (RDE) test in response to criticisms the current NEDC fuel economy test is outdated and misleading.

From 2017, the RDE test will become part of the type approval process for all cars sold in Europe. It will include an element of ‘real world’ driving using a portable emissions measurement system.

This means that emissions testing will move outside the laboratory for the first time, enabling real-world driving emissions to be compared with laboratory-tested results.

The news comes after The Sunday Times and testing company Emissions Analytics discovered that many Euro 6 diesel cars far exceeded lab-tested results in real-world driving.

The average variance was a hefty 4.4 times the legislated limit but some cars were far worse, particularly in terms of NOx emissions.

The firm did, however, report improvements over outgoing Euro 5 emissions of nearly 50%; “We believe the manufacturers, anticipating this legislative change, have really stepped up their game and the results are encouraging, although still mixed,” said Emissions Analytics CEO Nick Molden.

Car makers agree – but are concerned

European car manufacturers have agreed that “a new and fully updated Real Driving Emissions test is needed to better measure NOx emissions”.

The European car makers association, ACEA, did however add that “the decision is by no means the end of the discussion on RDE, as what was greed is just a partial set of evaluation conditions for real driving emissions”.

Mr Jonnaert, Secretary General of ACEA said: “ACEA calls on the Commission to urgently deliver a complete proposal for Real Driving Emissions by June or July at the latest for a positive decision in the regulatory committee. We need to make more progress on clarifying all testing conditions to ensure a robust RDE regulation could commence from September 2017.”

He did add that car makers are worried. “Automobile manufacturers remain concerned about the piecemeal approach the Commission is taking in preparing this proposal.

“This is not smart regulation. We need clarity in advance so that we can plan the development and design of vehicles in line with the new requirements.”