UK inquiry after Volkswagen scandal finds much higher nitrogen oxide levels than when vehicles are tested in laboratory

Diesel cars are producing many times more health-damaging pollutants than claimed by laboratory tests, with some emitting up to 12 times the EU maximum when tested on the road, according to a government investigation undertaken following the Volkswagen scandal.



A Department for Transport (DfT) study of cars made by manufacturers such as Ford, Renault and Vauxhall found there was a vast difference in nitrogen oxide emissions measured in the laboratory and under normal driving conditions.

Not a single car among 37 models tested against the two most recent nitrogen oxide emissions standards met the EU lab limit in real-world testing, with the average emissions being more than five times as high.

However, the DfT said it had found no vehicles outside the VW group with systems in place to deliberately rig emissions figures. Robert Goodwill, the junior transport minister, said: “Unlike the Volkswagen situation, there have been no laws broken. This has been done within the rules.”



The minister denied that the findings meant the current emissions testing regime was a farce. “But certainly I am disappointed that the cars that we are driving on our roads are not as clean as we thought they might be. It’s up to manufacturers now to rise to the real-world tests and the tough standards we’re introducing,” he said.

The DfT exercise was ordered after it emerged that Volkswagen had allegedly used technology to cheat emissions tests. It measured NOx, or nitrogen oxide emissions. Nitrogen oxide helps to form ozone smog that can badly affect people with chest conditions such as asthma.

The tests were carried out by a team led by Ricardo Martinez-Botas, professor of mechanical engineering at Imperial College London. Among the vehicles tested were 19 models that meet the latest Euro 6 limit of 80mg/km NOx emissions in laboratory tests. Euro 6 was introduced for all new cars sold after September last year.

When driven in a real-world simulation of urban, rural and motorway travel, the average was nearer to 500mg/km, with some cars getting close to 1,100mg/km.

Among the new models tested that are meant to comply with the Euro 6 standard were the Ford Focus, which had a real-world emission about eight times above the EU limit, the Renault Megane, whose emissions were more than 10 times higher, and the Vauxhall Insignia, almost 10 times higher.

Officials stressed that comparisons directly between models was unfair as they were all tested on different days, with varying temperatures and road conditions.

The study also revealed that none of the 37 top-selling vehicles that were claimed to have met the previous Euro 5 limit of 180 mg/km, in place from 2009 until last year, stayed within that legal level when driven on the road.

The models tested represented 50% of all diesel cars on the roads sold from 2010 to 2015, the report said.

The results do not mean any of the manufacturers other than Volkswagen have potentially broken any laws, because the only legal standard currently is to meet the lab requirement.

In the US it emerged that the of nearly 600,000 Volkswagen vehicles rigged to cheat on diesel emissions tests will have the option to have their cars fixed or bought back by Volkswagen, a federal judge said on Thursday.

VW may have to spend more than $10bn to comply with the agreement it has struck with the US Justice Department, according to analysts and sources briefed on the deal. The German carmaker admitted in September using sophisticated secret software to cheat exhaust emissions tests.

Industry experts said the car industry faced a crisis similar to recent banking scandals. David Bailey, professor of industry at Aston University, said the government, manufacturers and regulators needed to act on the results of the study.

“I liken this to the Libor crisis in banking. There is a fundamental question of confidence in the industry,

” Bailey said. “Clearly the testing regime needs to more accurately reflect the real world. That is not happening at the moment, not just in terms of nitrogen oxide but fuel efficiency. There is also an issue of accountability and openness for manufacturers in terms of what they put into public domain.”

In the wake of the tests, the government has promised to introduce new “real driving emissions tests” from next year. Initially, manufacturers will be able to sell cars that produce slightly over double the 80mg/km limit on the roads, but from 2020 this will fall to the actual limit.



The report found big variations depending on outside temperatures, with engines producing more emissions when it was cold.

Manufacturers told the DfT that devices to reduce emissions, called exhaust gas recirculation, tended to switch off when it was cold to protect the engine. This partly explained the lower lab emission readings, as these were taken at temperatures of about 20C.

The transport secretary, Patrick McLoughlin, said car manufacturers needed to take action. “Following the Volkswagen emissions scandal, the whole of the automotive industry must work hard to restore public trust by being transparent about the systems they employ and advancing plans for introducing cleaner engine technology.”

He added: “I’m disappointed the results are as bad as they are. We expected them to be different by a factor of maybe 0.5 or two on the road compared to the lab, but the levels are disappointingly high – industry needs to raise its game.”



The Society of Motor Manufacturers and Traders (SMMT), which represents the auto industry, said it backed the new real-world tests. A spokesman said: “The differences between the results from official laboratory tests and those performed in the real world are well known, and industry acknowledges the need for fundamental reform of the current official test regime, which does it no favours.

“SMMT and industry support the introduction of the proposed new and more onerous test, which will help to reflect better real-world driving.”

Friends of the Earth said properly stringent standards would take too long to come into force, with tens of thousands of people a year dying early because of poor air quality. “This confirms what experts have been saying for years: deadly emissions are far higher in the real world than in controlled tests in the lab,” said Oliver Hayes, from the group.

Jaguar Land Rover said its customers should be confident that its cars were “fully compliant with all current emissions legislations”. It added: “The results demonstrate that Jaguar Land Rover does not use any cheat devices or software. Jaguar Land Rover recognises that there is a difference between lab and real-world test results. We fully support the move towards real-world testing and the greater clarity this will bring for our customer.”

Mercedes said its vehicles had been “certified and licensed in accordance with the applicable legal requirements”. Vauxhall said it “welcomes the clarity provided by the report from the UK government”.

A Vauxhall spokesman added:



“Vauxhall is actively engaged in the discussion on RDE (real driving emissions). We strongly believe that the industry has to regain trust by increasing the transparency with customers and authorities, and we have taken definitive steps in this direction.”