Vehicles emissions data firm, Emissions Analytics has reported its latestÂ EQUA Air Quality Index which, it claims, shows some vehicle manufactures successfully tackling harmful NOx emissions, while others struggle.
The EQUA Air Quality Index for the European Union evaluates the performance of passenger cars in terms of tailpipe nitrogen oxide (NOx) emissions under road driving conditions.
In August, Volkswagen (VW) was the only manufacturer to achieve an A rating with a diesel vehicle in the new additions to the Index, the company said.
Meanwhile, some new diesel vehicles that entered in the Index this month(August 2016)Â are still emitting up to 12 times more NOx on the road as is allowed in official Euro-6 tests.
More than 20 new cars were added to the EQUA Air Quality Index in August, including models from a range of manufacturers including Audi, BMW, Hyundai, Mercedes-Benz, and Renault.
The new Volkswagen Tiguan 2.0 diesel is the fifth VW model and eighth Volkswagen Group vehicle to be awarded an A rating since the EQUA Index was launched earlier this year. According toÂ theÂ index company,Â this means the Tiguan’s real-world NOx emissions are less than or equal to the Euro-6 limit recorded in the laboratory.
Nevertheless, VW remains generallyÂ the focus of controversy following the emissions scandal surrounding its diesel cars, where the company was accused of having fitted â€˜cheating devicesâ€™ designed to manipulate emissions tests (see AirQualityNews.com story).
In contrast to the Tiguan, two new Renault models, the Espace 1.6 diesel and Megane 1.5 diesel, were both rated by Emissions Analytics, with the lowest H grade, meaning they emit more than 12 times as much NOx on the road as official tests suggest.
Also falling short was Hyundai, with the i40 1.7 diesel and Santa Fe 2.2 dieselâ€” both emitting up to eight times the Euro-6 NOx limit on the road, achieving an F grade.
Nick Molden, chief executive and founder of Emissions Analytics, said: â€œWe 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.
â€œHowever, there are still some new cars that are performing very differently in the real world to the laboratory.â€
EQUA Index ratings are published and freely available to all. Developed, funded and operated by Emissions Analytics, the EQUA Index allows manufacturers to “demonstrate their vehiclesâ€™ clean credentials and provide data to policymakers in the drive to improve air quality”.
Emissions Analytics is an independent provider of real-world emissions measurement and has carried out PEMS tests on more than 1200 model variants of passenger car in addition to testing heavy goods vehicles, tractors, taxis, vans and buses. It is currently in partnership with Imperial College, London, studying urban emissions for transport planning and policy.
In June, the company called on Government to take action after research revealed diesel cars could be emitting significantly more NOx pollution in cold weather (see AirQualityNews.com story).