29 nov 19

Mercedes Citan emits 17 times more NOx than VW Crafter

Still, they are both Euro 6 compliant. Cities should look at the real numbers rather than just the emission standards to reach air quality targets.

Independent road emission testing organism Air Alliance published the first ever Air Index ratings for vans with ten of Europe’s best-selling diesel light commercial vehicles (LCVs) tested.

Even though all of the tested vehicles comply with the Euro 6 emission standards, the differences in the actual NOx emissions are mind-blowing. The 2019 Mercedes Citan (a Renault Kangoo derivative) powered by a 1.5 diesel was found to emit nitrogen oxides at a rate of more than 600mg/km, whereas the Euro 6 limit for this vehicle class is 80mg/km, giving it an E rating.

A two years older and larger RWD 134bhp Mercedes Vito with the legacy 2.2 CDI performed a lot better and got a B label (80-160 mg/km). The even bigger VW Crafter is the cleanest van tested by Air Alliance, boasting an A label for the fact that its NOx emissions were below the 80 mg/km threshold.

Without specifying the specific emission results, Air Alliance found that a manual 2019 FWD VW Crafter 2.0 TDI 138bhp is 17 times cleaner than the aforementioned Mercedes Citan, highlighting that Euro 6 compliance in lab conditions is no guarantee for contained NOx emissions on the road.

That is why WLTP and RDE were introduced: new test protocols to close the gap between lab and road. The Real Driving Emissions test separates the- sometimes badly polluting – Euro 6b and 6c diesels from the (very clean) Euro 6d-temp diesels. Legally, they are not treated differently, though.

Limit city access to clean vans

Air Alliance believes this should change, citing Ireland’s announced NOx-based road taxation as a good way forward. But it goes one step further in its plea, calling on cities to look at the numbers rather than at the emission standard.

“There is a shocking variation in actual emissions compared with the official results based on laboratory tests,” said Massimo Fedeli, Co-founder and Operations Director, Air. “The Air Alliance is calling on cities to supplement the use of Euro 6 standards for low emission zone entry with the Air Index database of real-world emissions results, to identify the dirtiest vans which are otherwise slipping through the net. By doing so, we believe the Air Index could very quickly bring most European cities in line with air quality targets.”

The ten Euro 6 diesel vans tested by Air Alliance represent just under half of the annual sales across Europe. “If just those rated D or E were prevented from entering the centre of urban areas the  Air Index could bring all European cities into air quality compliance,” stresses Nick Molden, Co-founder of Air Alliance.

“But the ultimate responsibility to implement change lies with the manufacturers. With simple service-led engine management updates, it is possible to make vans much cleaner, dramatically reducing emissions immediately.”

For example, Air found that when it commissioned tests of the Mercedes Vito CDI 111 LWB 1.6, a simple manufacturer-led update of the vehicle’s emissions management system halved the NOx emissions when tested again.

Read more about diesel emission standards here.


Authored by: Dieter Quartier