Diesel emission scandal comes as no surprise

Volkswagen’s admission that they manipulated emission results may have shattered their share prices and crushed confidence but it was certainly no surprise.

Michel Cames, University of Luxembourg and Prof. Eckard Helmers, University of Applied Sciences Trier had long suspected something was amiss. We speak with the authors of “Critical evaluation of the European diesel car boom” to get an insight into the scandal.

ResearchGate: What was your initial reaction to the announcement that VW had installed software to deceive emission tests? Does it at all come as a surprise to you?

Michel Cames & Eckard Helmers: It felt like the missing piece to a puzzle. For years we knew that real-world emissions are on average around a magnitude higher than official test results, so it did not come as a real surprise.

RG: How did you find out about emissions being on average around a magnitude above official results?

MC & EH: In addition to the fact that hundreds of scientific papers have collected data on this, the International Council on Clean Transportation (ICCT) released an​ ​independent investigation revealing that average on-road nitrogen oxide emissions were seven fold higher than limits set by the European Union.

Furthermore, a unique report gave us a valuable insight into “real-world” emissions. The report showed us what was actually happening in the European Union: ​while the EU was decreasing its nitrogen oxide emission thresholds from Euro 0 to Euro 6, nitrogen oxide emissions were actually increasing in the “real world”. Even though emissions have recently decreased, they still remain where they were 20 years ago. ​Despite all the evidence, public discourse continues to propagate this myth that nitrogen oxide emission of diesel cars are decreasing which never actually happened.

RG: Could a diesel car achieve those results under real-life driving conditions?

MC & EH: It could, but only if it is equipped with SCR-catalyst/urea injection. This is a treatment system that filters and converts dangerous chemicals when it is adjusted accordingly. Also, engine tuning would need to be perfect, and the diesel car would have to be new because most of the old cars have some type of engine malfunction.

RG: Furthermore, what does this say about the emission tests themselves?

MC & EH: Emission tests in Europe are unrealistic. They are based on highly modified vehicle bodies that lower fuel consumption to levels that are not achievable in reality. Newly tested engines only need to be valid for the first 150,000 km (in contrast, US cars have to meet emission thresholds for up to 240,000 km). They are also subject to interferences from stakeholders; the testing is not independent. Carmakers actually contract the tests to organizations themselves. These organizations are commercial enterprises that compete for business.

RG: What sort of damage will this scandal do to VW and the diesel car industry in general?

MC & EH: The damage to VW is already obvious. Diesel cars in Europe may also face more questions in the future. So far, the emission focus was only on greenhouse gases as regulated in the Kyoto protocol, but the diesel car industry should also have to critically approach its pollutants, like nitrogen oxide. Although they “did”, it was not effective in the real world.

RG: Could this scandal see Europe make a shift away from diesel technology? Maybe in a similar direction to Japan and its focus on petrol-hybrid cars? Or to electric, full-stop?

MC & EH: We'd hope so at least! It is still too early to see what any shift may be. Politics and industry may be tempted to avoid admitting that diesel was the wrong road to take decades ago and just push for a faster conversion away from the combustion engine. However, they will need to make quick inroads into ongoing petrol-hybrid research to keep with Europe's greenhouse gases targets. The scandal should also exert extra pressure on the EU Commission and the Member States to reevaluate their long term diesel fuel tax incentive.

RG: VW’s unleashed tons of extra pollutants in the United States and Europe as a result of the cheating software. What sort of environmental impact could pollutants like nitrogen oxide have on global warming and on human health?

MC & EH: Nitrogen oxide emissions are a precursor for ozone. Tropospheric ozone is responsible for some 20 % of manmade greenhouse effect. Nitrogen oxide causes allergies, cancer, bronchitis and cardiovascular diseases.

RG: In your paper you write that nitrogen oxide emissions have been underestimated 20 fold in official data. Why is that so? How likely do you think it is that other carmakers manipulated their data too?

MC & EH: Exhaust treatment systems are either absent or were not optimized to minimize emissions during real driving conditions but rather to optimize power, torque and CO2. There is an evident trade-off between nitrogen oxide emissions and power, torque and CO2.

Other carmakers may as well have manipulated their data, especially if they pretend their vehicles have low nitrogen oxide emissions without the SCR-catalyst/urea injection system equipped.

Image courtesy of Sal