Most Diesel Cars Emit More Emissions Than Legal Limit: Report

Jason Siu
by Jason Siu

Essentially every diesel vehicle on today’s roadways emit more emissions during everyday road driving than they do in testing.

According to a recent report from The Guardian, Volkswagen isn’t the only automaker that has diesel vehicles sharing too much NOx pollution with the world.

The publication first reported that Renault, Nissan, Hyundai, Citroen, Fiat, Volvo and Jeep all had diesel vehicles that emitted more NOx in realistic driving conditions than compared to testing and now it has added Mercedes-Benz, Honda, Mazda and Mitsubishi to the list.

In on-road tests, some Honda models emitted six times the regulatory limited or NOx pollution while unnamed 4×4 models showed 20 times the amount.

Although all the diesel vehicles tested passed the EU’s official lab-based regulatory test, they have failed to cut air pollution because the vehicles were designed to perform better in the lab than on the road.

SEE ALSO: VW Top Brass Learned About Cheat in September, ‘Major Fix’ Planned: US CEO

Unlike Volkswagen however, these other automakers show no indication that they used defeat devices or engaged in illegal activity in order to achieve these results. It appears more likely that “the issue is a systemic one,” said Nick Molden, whose company Emissions Analytics tested the cars.

In testing, Emissions Analytics analyzed about 50 Euro 6 diesels and 150 Euros 5 diesels and found only five had real-world NOx levels that matched the regulatory test.

“The VW issue in the US was purely the trigger which threw light on a slightly different problem in the EU – widespread legal over-emissions,” Molden said. “For NOx, [diesel] cars are on average four times over the legal limit, because of the lenient nature of the test cycle in the EU.”

[Source: The Guardian]

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Jason Siu
Jason Siu

Jason Siu began his career in automotive journalism in 2003 with Modified Magazine, a property previously held by VerticalScope. As the West Coast Editor, he played a pivotal role while also extending his expertise to Modified Luxury & Exotics and Modified Mustangs. Beyond his editorial work, Jason authored two notable Cartech books. His tenure at saw him immersed in the daily news cycle, yet his passion for hands-on evaluation led him to focus on testing and product reviews, offering well-rounded recommendations to AutoGuide readers. Currently, as the Content Director for VerticalScope, Jason spearheads the content strategy for an array of online publications, a role that has him at the helm of ensuring quality and consistency across the board.

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  • Jonny_Vancouver Jonny_Vancouver on Oct 09, 2015

    Good article. That would make sense if it was an inherent flaw in the testing system and/or how diesel vehicles operate in general, but regarding the VW scandal let's not forget that they blatantly lied to everyone and took the extra step of installing cheat software, and there's no excuse for that.

  • Smartacus Smartacus on Oct 09, 2015

    the only ones not on the list of offending diesels: Ford, GM