Europe’s cleanest diesel cars still fail strict EU emissions rules

Even the cleanest diesel cars currently on the roads do not meet EU emissions standards, according to field measurements performed by TNO. Not a single tested diesel car comes to being below the emission limit of 80 milligrams of nitrogen dioxide per kilometer. 

The tested cars emit an average of three to five times more nitrogen dioxide than in the approval test - the test in which a car is put on a chassis dynamiter. If the cars are subjected to extreme conditions - speeding or hard braking for example - they are even 10 to 20 times above the limit.

The Volkswagen Passat CC, the BMW 518, the Mercedes Benz C220 and the Opel Zafira in particular performed badly in the field tests. The Audi Q7 and the Peugeot 308 also did not do well. Only the BMW 530 came relatively close to meeting EU standards.

TNO added that the published figures only give an indication and that the tests varied too much to be able to make clear judgement on car manufacturers. The researchers also emphasized that the test results do not automatically mean that the car manufacturers used tampering software, as was the case in the Volkswagen Diesel scandal.

From next year, new tests are mandatory for cars in Europe, which should give a better picture on what cars emit in practice.