Diesel Cars Pollute 50 Percent More Than Previously Thought, Study Says

Which means diesel was reportedly responsible for 38,000 more premature deaths than we thought. 

Christophe Gateau/picture-alliance/dpa/AP Images

Diesel is dirty business. In spite of the best efforts of automakers to clean the fuel up with urea and other additives in recent years, the oily fuel emits far more nitrogen oxide emissions than gasoline—the karmic price to pay for its superior fuel economy. And while we've know that diesel wasn't great for the environment (or the people in it) for some time, we're still learning just how bad they really are. A new study has found that diesel vehicles from 10 major regions around the globe actually produced 50 percent more nitrogen oxide than scientists previously thought.

According to a study published this week in the journal Nature, researchers measured tailpipe emissions from diesel cars and trucks in 10 markets—the United States, China, the European Union, Mexico, Russia, Canada, Australia, South Korea, Brazil, Japan, and India—whose citizens buy around 80 percent of the oil-burning road vehicles on the planet. When compared with the lab-based test results, they found that, based on their field testing, vehicles were actually emitting about 14.4 million tons of nitrogen oxide—5 million more than the previous testing had led scientists to believe.

Those additional millions of tons of NOx and other nasty diesel tailpipe crap being blasted into Earth's atmosphere, according to the researchers, add up to around an additional 38,000 ozone and particulate matter-related deaths in 2015 alone. (Obviously, that doesn't mean 38,000 more people died than we previously thought—it just means diesel pollution had a hand in more fatalities than we realized.) That means diesel was responsible for 10 percent more deaths in Europe than previously believed, for example, as well as an additional 1,100 deaths that year alone in the U.S.

The study could be seen as yet another nail in diesel's coffin, considering the horde of bad PR the fuel has been accumulating. In addition to the Volkswagen Dieselgate scandal, the Fiat Chrysler diesel inquiry, and probes into Daimler among other brands—the burden of which lies more with the companies than the fuel, but still does little to further diesel's reputation—doctors in Great Britain have begun attacking the oily fuel en masse, with a group now engaged in a full-scale lobbying effort to rid the country of it.

Still, don't assume diesel's days are done. The study's authors point out that adopting stricter emissions standards—ones that go beyond current plans—could all but eliminate diesel deaths, saving hundreds of thousands of live over the next few decades.