Engineering news
The report, published in Nature, says strict new regulations must be introduced in several countries to limit the release of the dangerous gases. The international team of researchers, led by Susan Anenberg at Environmental Health Analytics in the US, said limits are needed to prevent a projected 104,000 premature deaths in 2040.
In Australia, Brazil, Canada, China, the European Union, India, Japan, Mexico, Russia, South Korea and the US, the group said over half of emissions from light-duty diesel vehicles, such as cars, break legal limits for nitrogen oxides (NOx). In the same areas, which make up 80 % of new diesel vehicle sales, the report claims nearly one third of emissions from diesel heavy goods vehicles (HGVs) are over legal limits.
The authors said the vehicles were responsible for releasing 4.6 million tonnes of NOx above certification levels in 2015, with HGVs found to be the biggest contributor in all areas apart from the EU. The gases are associated with respiratory problems, including inflammation of the lung lining and susceptibility to bronchitis, according to the Healthy Air Campaign.
The research team also found that diesel vehicles emit far more NOx in “real world” conditions compared to laboratory testing. The disparity is down to issues with the New European Driving Cycle (NEDC) test, which was designed for “precision rather than realism,” said Chris Brace, engineer at the Centre for Low Emission Vehicle Research, to Professional Engineering.
Previous modelling of NOx emissions was also inaccurate because “the mix of vehicle types, ages and state of maintenance in a model is difficult to match to real city conditions,” he added. Researchers said the Volkswagen emissions scandal, where illegal “defeat devices” were installed to limit emissions during laboratory testing, was also found to be a dominant factor in the amount of NOx released in the EU.
The strictest emissions standards for HGVs, known as Euro 6, should be implemented in Brazil, Mexico, China and Russia, said the researchers. The regulation limits NOx emissions to a maximum of 80mg/km, down from 180mg/km. They claim the move would reduce two thirds of the global impacts of excess diesel NOx emissions. “Making these changes is important because it would improve human health and minimize the impacts of air pollution on crop production,” engineer and contributor Daven Henze from the University of Colorado told PE.