Diesel Euro 6 vehicles continue to deliver drastically different nitrogen oxide (NOx) emissions when tested in the real world, with some models meeting official targets while others are up 12 times over.

Emissions Analytics uses a portable emissions measurement system to compare standards.

The latest EQUA Air Quality (Aq) Index results from Emissions Analytics show the BMW 520d auto and Mercedes C220d auto both produced NOX in line with official figures in the company’s tests – giving them an A rating, while the BMW 216d Active Tourer recorded the second-highest band of pollution, equating to roughly 8-12 times the Euro 6 limit and scoring it a G.

Emissions Analytics said the results show it remains difficult to pick the ‘saints from the sinners and underscore the need for real-world testing to tackle “issues that can have a serious impact on health”.

The company also noted that yet again, petrol models performed far better, with all new models hitting the top mark for air quality apart from one, which was only one band adrift. Meanwhile the results also showed that the latest petrol hybrid models from Lexus and Toyota were all in line with legislation.

The new EQUA Air Quality (Aq) Index also include the latest petrol hybrid models from Lexus and Toyota – all of which were in line with legislation. To date, all Euro 6 hybrid vehicles accessed have produced real-world results in line with official targets.