Diesel vehicles produce 50 percent more nitrogen oxide than originally thought

Credit: Steffen Thoma/Public Domain

The research, led by the International Council on Clean Transportation and Environmental Health Analytics, LLC., in collaboration with scientists at the University of York's Stockholm Environment Institute (SEI); University of Colorado; and the International Institute for Applied Systems Analysis, examined 11 major vehicle markets representing more than 80% of new diesel vehicle sales in 2015.'

Of these markets, they found vehicles emitted 13.2 million tons of nitrogen oxide under real-world driving conditions, which is 4.6 million tons more than the 8.6 million tons expected from vehicles' performance under official laboratory tests.

Chris Malley, from the SEI, University of York, said: "This study shows that excess nitrogen oxide emissions effect crop yields and a variety of human health issues. We estimate that implementing Next Generation standards could reduce crop production loss by 1-2% for Chinese wheat, Chinese maize, and Brazilian soy, and result in an additional four million tonnes of crop production globally."

Nitrogen oxide is a key contributor to outdoor air pollution. Long-term exposure to these pollutants is linked to a range of adverse health outcomes, including disability and reduced life expectancy due to stroke, heart disease, chronic obstructive pulmonary disease, and lung cancer.

Josh Miller, researcher at the International Council on Clean Transportation (ICCT), said: "Heavy-duty vehicles, such as commercial trucks and buses, were by far the largest contributor worldwide, accounting for 76% of the total excess gas emissions.

"Five of the 11 markets that we looked at, Brazil, China, the EU, India, and the US, produced 90% of that.

"For light-duty vehicles, such as passenger cars, trucks, and vans, the European Union produced nearly 70% of the excess diesel nitrogen oxide emissions."

The study estimates that excess diesel NOx emissions in 2015 were also linked to approximately 38,000 premature deaths worldwide - mostly in the European Union, China, and India.

Susan Anenberg, co-Founder of Environmental Health Analytics, LLC, said: "The consequences of excess diesel NOx emissions for public health are striking. In Europe, the ozone mortality burden each year would be 10% lower if emissions were in line with certification limits."

At a global level, the study estimates that the impact of all real-world diesel will grow to 183,600 early deaths in 2040, unless something is done to reduce it. In some countries, implementing the most stringent standards - already in place elsewhere - could substantially improve the situation, according to the researchers.

Explore further

Nearly 30 mn diesel cars on EU roads over emissions limit: study

More information: Impact of excess diesel emissions on premature mortality, Nature (2017). DOI: 10.1038/nature22086
Journal information: Nature

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User comments

May 16, 2017
I'm willing to bet the diesel vehicle manufacturers rigged their engine performance to overperform on official lab tests used to regulate them so they can get away with underperforming in actual driving. Just ask Volkswagen (which will probably still deny it even after getting badly caught cheating). There are very rarely any major car manufacturers doing anything very different from all the rest.

May 17, 2017
Huh. Here's a big new factor that climate scientists knew absolutely nothing about.

And I thought they had this stuff all figured out.

May 17, 2017
No, because of all the industrial and political pressure on climate scientists they are forced to underestimate how bad our trajectory is. Nobody thinks they have it *all* figured out: after all, they're at work today doing more science, figuring more out. Now they're working on figuring out how much worse cars have made our future survival.


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