Emissions Analytics has produced research showing the level of Nox emissions seen in Euro 6 vehicles is up to 72% lower than Euro 5.

Extensive tests conducted to date show that the newer, Euro 6 diesel engines exhibit marked improvements when it comes to the production of emissions harmful to health.

With over 350 diesel vehicles analysed so far, Emissions Analytics’ data shows the earliest Euro 6 diesels produced levels of NOx significantly above the legislated limits.

As reported in the International Council on Clean Transportation’s 2014 report, to which Emissions Analytics contributed data, the average was seven times over the limit.

Recent Euro 6 diesels show marked improvement, with NOx levels averaging around 2.5 times the legislation limit of 0.08g/km.

“The regulation change to Euro 6 has reduced the permitted levels of NOx by 55% but, in real terms, the very latest Euro 6 diesels that we’ve tested are showing an improvement on Euro 5 of 72%,” explained Nick Molden, CEO of Emissions Analytics.

Secondly, a large proportion of NOxis emitted during stop-go urban driving - particularly while a vehicle is accelerating.  This is one of the principal contributors towards urban air quality problems, and underlines the importance of looking beyond the headline numbers.

Molden added: “To claim that all diesels are dirty misrepresents a complex situation. While it is certainly true that older diesel vehicles, including passenger cars, buses, taxis and delivery vehicles are significant contributors to poor air quality, our data shows that, with the introduction of the latest Euro 6 vehicles, the situation is improving. What this shows us is the important role real on-road emissions testing has to play in cleaning up our towns and cities.”