Researchers discover 'suspicious' exhaust emission values in diesel vehicles in Europe

By Timo Kirez

GENEVA (AA) - An analysis of tests and studies conducted over several years by the international environmental research alliance ICCT has found significantly excessive exhaust emissions from many diesel cars in Europe, the researchers announced Thursday.

According to the results, 85% of Euro 5 and 77% of Euro 6 diesel vehicles showed "suspiciously high emissions," they said.

In 40% of the cases, even "extreme" values for harmful nitrogen oxides (NOx) were found.

Some rulings of the European Court of Justice (ECJ) on the so-called switch-off devices required their "reassessment." According to these rulings, the cleaning system may only be shut down if there is a threat of concrete technical damage and safety risks.

According to the ICCT, the data covers approximately 700,000 cars from various European countries. The scientists took different measurement methods into account.

For the most part, the so-called "remote sensing" was used -- exhaust gas values of passing cars were measured from the roadside, along with tests using mobile measuring devices on the exhaust.

The values determined in this way were then related to a threshold value for the respective engine and vehicle type. This was derived "on the basis of the exhaust gas cleaning behavior normally to be expected," the ICCT said.

The researchers interpreted the deviations to mean that for diesel cars with NOx emissions classified as "extreme", "the use of a switch-off device could be considered almost certain."

Slightly less-elevated values also indicated the "likely use of an engine calibration strategy, which can be classified as a prohibited switch-off device under recent ECJ rulings."

The ICCT had triggered the so-called emissions scandal in 2015, after which the research and environmental organization found nitrogen oxide levels far above the permissible limits in on-road tests of some vehicles, and subsequently alerted the US Environmental Protection Agency.

The evidence ultimately led to the uncovering of the "Dieselgate" affair, the biggest industrial scandal in post-war history.

The diesel share of new registrations has been declining year after year everywhere in Europe since then. Even in January 2023, the number of new registrations for diesel vehicles fell by 1.6%, according to the European Automobile Manufacturers' Association, and the market share fell from 17.9% to 15.9%.