We all kind of knew this to be the case. Our eyes told us. Our noses told us. Common sense assured us. Diesel engines aren’t environmentally sound. Yet, carmakers pounded us with references to “clean” diesel. Supposedly, oil burners were every bit as harmless as almost anything else on the road. We knew that was unlikely. Now, we know for sure. “Clean” diesel isn’t clean. Recent independent tests run by The Real Urban Emission Initiative (Known in Europe as “True”) proved the case our nostrils made long ago. Gildshire and Motor1 combined with the research effort.
The True coalition tested almost 5,000 models. Every last diesel up to the latest iteration, known as Euro 6, received a poor rating. That didn’t surprise us. But, the majority of Euro 6 diesel cars were judged “below standard” or “poor” as well. By contrast, all Euro 6 gas engines received a good or moderate rating. The TRUE study also found that that the highest-polluting gas Euro 6 vehicle has about the same level of noxious emissions as the best-performing diesel engine.
Earlier models performed even more spectacularly poorly. Every Euro 5 diesel model tested had noxious emissions at least twice the legal limit. The worst one checked in at an eye-watering 18 times the legal limit.
“If I was a customer, I would look at these figures at the moment and have to conclude I should not buy a diesel car,” said Peter Mock of the International Council on Clean Transportation. “Even Euro 6 diesel vehicles are not performing well at the moment so pretty much all of them should not have access to city centers.”
The latest tests may be the beginning of the death rattle for a less-than-popular segment of vehicles. Diesel engines have steadily declined in popularity since mid-2015. That was when it first emerged that Volkswagen fitted its cars with so-called “cheat devices.” These cheaters enabled VW’s cars to pass emissions examinations while under lab conditions, all the while polluting the air when on the open road. Since the VW scandal, stricter legislation has been enacted, and some larger cities have new rules that keep diesel-engined cars from entering certain areas.