The firm has released details of the latest engines to be awarded an A rating for low NOx emissions under its EQUA Air Quality Index, with Ford’s 1.0-litre EcoBoost, as well as Bentley’s 6.0-litre W12 and Rolls-Royce’s 6.6-litre V12 all making the grade.

Emission Analytics’ testing showed that the current Ford Focus 1.0 EcoBoost 125 manual produced roughly 85% less NOx when recently tested. In addition the firm said that the new Bentley Bentayga 6.0-litre W12 and Rolls-Royce Dawn 6.6-litre V12 have also received an EQUA Index A rating – in both cases the engines produce less NOx than 100% of the Euro 6 diesel engines listed on the EQUA Index.

Nick Molden, CEO and founder of Emissions Analytics, said: “It’s encouraging to see that vehicle manufacturers are cleaning up engine emissions as part of a continuous development programme. Both large and small displacement engines are capable of hitting the latest targets if correctly optimised.”

In total, 18 cars were added to the EQUA Index this month, all of which were Euro 6 models, joining more than 470 vehicles ratings that are available from www.equaindex.com. The programme will continuously add new vehicles to its database.