Still plenty to be done
Emissions Analytics provide valuable insight to the debate on just how clean modern diesel engines are with its real, on-road vehicle emissions data.
Far from being a simple case of all diesels being equal, the 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 NOxsignificantly above the legislated limits. As reported in the International Council on Clean Transportation’s 2014 report, the average was seven times over the limit.
However, many recent Euro 6 diesels show marked improvement, with NOxlevels 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%,” explains Nick Molden, CEO of Emissions Analytics.
While this shows that there is still progress to be made, the recent demonisation of diesel misrepresents the work that vehicle manufacturers have undertaken to improve air quality and reduce the effects of transport-derived health issues, such as asthma. In addition, the introduction of diesel particulate filters at the Euro 5 stage went a long way to clean up the solid matter emitted from the exhaust.
A deeper dive into Emissions Analytics’ data shows that there are further considerations beyond the headline NOxnumbers.
Firstly, the percentage of NO2 in the NOx is an important consideration as NO2 is the major contributor to pollutant-related health issues. A recent presentation made by Emissions Analytics revealed that the ratio of NO2to NOxcan be as high as 90% in urban driving.
Secondly, a large proportion of NOx is 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.
Nick Molden concludes: “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.”
