Some new diesel vehicles are still emitting up to 12 times more toxic Nitrogen Oxide (NOx) on the road than is allowed in official laboratory tests, although emissions from a new Volkswagen model are within current limits.
Emissions Analytics, specialists in real-world, on-road vehicle emissions measurement and analysis, has published its latest EQUA Air Quality Index, which compares the real-world emissions of new cars with European regulations.
The VW Tiguan 2.0 was the only diesel to achieve an A rating
Ironically, VW, which last year admitted using software to cheat lab tests, is the only manufacturer to achieve an A rating for a diesel vehicle, with its new Tiguan 2.0 diesel. This means that its real-world NOx emissions are less than or equal to the Euro 6 limit recorded in the laboratory.
Emissions Analytics said the Tiguan was the fifth VW model and eighth Volkswagen Group vehicle to be awarded an A rating since the EQUA Index was launched earlier this year.
More than 20 new cars were added to the EQUA Index in August, including models from Audi, BMW, Hyundai, Mercedes-Benz, and Renault.
Two new Renault models, the Espace 1.6 diesel and Megane 1.5 diesel, were rated at the lowest, H grade, meaning that they emit more than 12 times as much NOx on the road as official tests suggest.
The Hyundai i40 1.7 diesel and Santa Fe 2.2 diesel were both found to emit up to eight times the Euro-6 Nox limit on the road, thereby achieving an F-grade.
Nick Molden, CEO of Emissions Analytics, said: ‘We continue to see a number of encouraging results from vehicle manufacturers such as Volkswagen, which show that a number of new diesel engines are as clean on the road as they are under official tests. However, there are still some new cars that are performing very differently in the real world to the laboratory.’
In April, the Department for Transport said all makes of diesel cars it tested produced significantly higher NOx emissions in real world tests than in labs, with the worst performing car models also up to 12 times more polluting and even the best almost twice as polluting.
New European legislation coming into effect in 2017 will allow real-world emissions to exceed the lab-testing limit by a maximum 2.1 times.
Emissions Analytics said its EQUA Index provides an easy to understand sticker clearly showing each car’s performance and allows manufacturers to demonstrate their vehicles’ clean credentials, and provide data to policymakers on progress in the drive to improve air quality.
It is intended to complement the forthcoming Real Driving Emissions regulations for new vehicle certification, and the firm said it would will help monitor vehicle performance when driven normally on roads, and the effectiveness of new regulations.