The auto industry has been rocked by revelations that Volkswagen, the largest automaker in the world, rigged its emissions tests in the US to get around laws and increase sales. Martin Winterkorn, the company’s chief executive, resigned on September 23 after the company acknowledged on September 22 that it had employed special software to reduce emissions during laboratory testing of some of its diesel vehicles. As of September 25, the US Environmental Protection Agency (EPA) announced that US automakers would now have to pass more difficult emissions tests.
According to the company’s disclosure, about 500,000 cars in the United States and 11 million globally may be releasing significantly more nitric oxide and nitrogen dioxide (often referred to as nitrogen oxides, or NOx) into the atmosphere than is predicted by laboratory testing. It’s unclear what the scandal means for human health, and some believe it may still affect other automakers. However, experts have long known that lab studies frequently significantly underestimate real emissions from diesel vehicles.
How were the manipulations discovered?
Scientists from the Center for Alternative Fuels Engines and Emissions at West Virginia University in Morgantown were hired by the International Council on Clean Transportation (ICCT) in Washington, DC, last year to test the emissions from three light-duty diesel vehicles under more realistic conditions than could be achieved in a lab. The scientists accomplished this by equipping vehicles with portable emissions measurement equipment, which allowed them to continuously collect data over a range of US road conditions.
Depending on the road and driving circumstances, the tests revealed that the NOx emissions from a Volkswagen Jetta were 15–35 times higher than the US guideline, which is set at 31 milligrams per kilometre. Similarly, a Volkswagen Passat had five to twenty times higher values.
The results led the US Environmental Protection Agency (EPA) to begin looking into Volkswagen’s testing in the country. Additionally, the EPA threatened to revoke its clearance for any Volkswagen diesel vehicles permitted for sale in the country. In response, Volkswagen acknowledged that it had manipulated emissions testing by utilising software that detects when the vehicle is being tested and activates full emissions control.
Why should we be concerned about diesel emissions?
Since diesel engines are far more common in Europe than they are in the US, diesel exhaust is a significant source of air pollution. Diesel emissions are associated with harmful health impacts, particularly carbon monoxide and NOx. Volkswagen’s manipulations mostly affected NOx emissions, which are a precursor to ground-level ozone and can lead to severe respiratory issues.
In London, diesel vehicle traffic accounts for 40% of NOx emissions, which are linked to air pollution and over 3,000 deaths annually. It is estimated that 20% of urban residents in the European Union reside in regions where nitrogen dioxide concentrations are higher than permitted levels.
What issues with emissions testing were recognised before Volkswagen’s acknowledgement?
Numerous studies have demonstrated that the NOx emissions from diesel passenger cars – including those manufactured by automakers other than Volkswagen—when driven on public roads significantly surpass the levels recorded in lab settings. The outcomes have sparked questions about the viability of the current regulatory processes, which automakers must clear if they want to release a new model into the market.
The Joint Research Centre (JRC) of the European Commission in Ispra, Italy, revealed in 2011 that the average on-road emissions of tested diesel vehicles exceeded permissible limits by as much as 14 times1. In contrast, petrol vehicles’ NOx emissions remained under the permitted range.
A year later, the JRC compared the NOx emissions of six older-model cars with a diesel passenger car named Euro 6, designed to meet the 2014 emissions regulations. The new automobile model did perform much better on the road thanks to its sophisticated catalytic converter, but it still surpassed the current emissions standard by almost 260%.
However, an analysis conducted by the ICCT in October of the real-world emissions of fifteen contemporary diesel cars—twelve certified to the EU standard and three to the US standard equivalent—found that while some vehicles operated fairly well, others had real-world emissions up to 25 times higher than the 80 milligrams per kilometre permitted by the Euro 6 regulation. About seven times as much NOx was emitted on average compared to what the EU permits.
Does Volkswagen stand alone in using software meant to evade testing?
The use of so-called “defeat devices” may be more common than previously thought, even though no other manufacturers have been linked to this. “I personally find it hard to believe that Volkswagen was the only brand to do it,” remarks Jos Dings, director of Transport & Environment, a non-governmental group located in Brussels. Citing research published by Transport & Environment, he says Volkswagen was just one of several businesses using diesel cars with emissions over legal limits on the road. The study was limited to Europe where diesel emissions regulations are less strict, and did not, however, search for proof of deception.
What is happening now?
Europe had already implemented measures to improve diesel emissions tests before the scandal. The European Commission planned to establish ‘Real Driving Emissions’ tests for all passenger vehicles, ensuring on-road compliance with NOx emission limits. Similarly, the US EPA announced updates to emissions testing standards after the scandal, allowing spot-checks on new diesel vehicles using portable emissions measurement systems. This expanded testing includes light-duty diesel vehicles—a small fraction of the US car fleet and highway pollution.
Does that mean the problem will be resolved?
The suggested modification has the potential to significantly reduce the emissions from new cars, and experts anticipate that it will incentivise automakers to produce vehicles that adhere to the regulations. Future testing conditions, however, still need some aspects to be worked out. Automakers would rather have specific requirements for on-road testing. However, experts warn that the broadest possible emissions test is necessary for meaningful results.
What implications does the controversy have for diesel vehicles going forward?
Diesel vehicles have been promoted as a way to reduce global warming since they typically have a lower carbon footprint than their gasoline-powered equivalents. Furthermore, diesel vehicles may keep emissions under current regulations.
However, experts warn that Volkswagen’s improper actions could lead to increased emission regulations, increasing automakers’ expenses for R&D and investment. Additionally, the controversy may make it harder to convincingly argue that diesel use is compatible with efforts to lower air pollution.
(Tashia Bernardus)