Diesel was, for a time, considered by some to be a greener alternative to unleaded gasoline. Those days seem numbered, as the environmental case against the fuel is starting to look stronger. As the AP reports, new research suggests that diesel’s pollution is being grossly underestimated all over the world:
The work published Monday in the journal Nature was a follow-up to the testing that uncovered the Volkswagen diesel emissions cheating scandal. Researchers compared the amount of key pollutants coming out of diesel tailpipes on the road in 10 countries and the European Union to the results of government lab tests for nitrogen oxides.
They calculated that 5 million more tons (4.6 metric tons) was being spewed than the lab-based 9. 4 million tons (8.5 million metric tons). Governments routinely test new vehicles to make sure they meet pollution limits.
Experts and the researchers don’t accuse car and truck makers of cheating, but say testing is not simulating real-world conditions.
Europe has a long history of gaming its car emissions tests, and it’s a history we’ve been following for some time. Testers get creative to juice extra mileage out of vehicles, employing such novel techniques as removing side-view mirrors to reduce drag, taping up doors, and removing “extras” like stereos to make vehicles lighter.
This lax testing has made diesel to seem more environmentally friendly than it actually is. Diesel’s green case was dubious to begin with, though: the fuel emits more local air pollutants than gasoline, and has been blamed for the recent rise in toxic smog in many of Europe’s biggest cities. Europe saw this as an acceptable trade-off, however, because diesel is capable of getting higher mileage.
But it seems as if those local pollutants being spewed out of the tailpipes of diesel-powered cars and trucks are a bigger problem than previously believed. So much for Europe’s “green” credibility.