Because of testing inefficiencies, maintenance inadequacies and other factors, diesel cars, trucks and buses worldwide emit 4.6 million tons more harmful nitrogen oxide (NOx) than standards allow, according to a new study co-authored by University of Colorado Boulder researchers.
The study, published today in Nature, shows these excess emissions alone lead to 38,000 premature deaths annually worldwide, including 1,100 deaths in the United States.The findings reveal major inconsistencies between what vehicles emit during testing and what they emit in the real world – a problem that’s far more severe, said the researchers, than the incident in 2015, when federal regulators discovered Volkswagen had been fitting millions of new diesel cars with “defeat devices.”