Emissions testing firm highlights ‘issues with diesels’

Emissions Analytics commends new diesel improvements but says real-world emissions are still seven-times above limits

A vehicle emissions research firm has backed the UK motor industry’s claims that diesel engines are being disproportionately ‘demonised’ over air pollution, but stressed that there are still “issues with diesels that are not captured by the regulations”.

Winchester-based Emissions Analytics said the newest Euro 6 standard diesels had shown considerable reductions in emissions compared to older models.

Emissions Analytics said NOx emissions from newer diesel engines had improved but were still above limits

Emissions Analytics said NOx emissions from newer diesel engines had improved but were still above limits

But, the firm said that its own real world testing found that some of the earliest Euro 6 engines on the market still produced levels of NOx which were “seven times above the legislated limits”, adding that “in our opinion, the evidence from real-on-the-road tests speaks for itself”.

Furthermore, the firm explained that current regulations do not take into account the proportion of NOx emissions that are nitrogen dioxide (NO2), which is “the more harmful component”. It added that its research shows that the proportion of NOx emitted as NO2 “can be as high as 90% in urban driving, much higher than generally acknowledged”.

Emission’s Analytics’ statement came in response to the Society of Motor Manufacturers and Traders’ (SMMT) ‘myth-busting’ diesel campaign launch last week (March 11), which sought to challenge what it described as the “increasing demonisation of diesel” over the impact of these vehicles on air pollution (see story).

Launching the campaign, SMMT — which includes motor vehicle firms such as BMW, Ford, Volkswagan and Jaguar Land Rover — had urged policy makers and local authorities to “avoid confusing motorists” and argued that the latest diesel cars are the “cleanest in history”, which prompted criticism from air quality campaigners.

And, highlighting its own research on vehicle emissions, Emissions Analytics agreed that that the newest Euro 6 standard diesels are bringing “marked improvements, with NOx levels averaging 2.5 times above the legislated limit”.

It also said that “great strides” have also been made to improve emissions from new buses.

Furthermore, Emissions Analytics said that the introduction of diesel particulate filters (DPFs) had addressed the issue of particulate matter emissions from the vehicles, and it praised the impact of regulations and industry investment on reducing emissions.

As a result, the research firm said: “This can only be to the benefit of urban air quality and thus we agree with the SMMT in that a simplistic ‘demonisation’ of new diesels is not correct. In fact, careful attention needs to be paid to other technologies creating emissions increases, such as direct injection gasoline engines.”

However, the firm also highlighted its own research showing that diesel cars of Euro 5 standard or earlier “are indeed ‘dirty’” as they produce high levels of NOx which is harmful to human health and “particularly bad in urban environments” due to the stop-start nature of city driving.

Emissions Analytics added: “And, it is made worse by the high number of older diesel buses, taxis and delivery vehicles in the urban environment.”

Emissions Analytics is now conducting research into vehicle emissions in partnership with the likes of Imperial College London in order to “ensure that the clean-up of diesel engines continues to translate into reality”.

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