DVSA Report Confirms High Risk of Low Emission Zone Failures From Over-Emitting Euro 6 Vehicles

  • Allow Independent Road-testing (AlR), the publishers of the AIR Index, the independent, standardised on-road emissions rating system, welcomes clarity from the government’s latest emissions test results published this week by the Driver and Vehicle Standards Agency (DVSA).
  • The AIR Index ratings confirm the DVSA findings which show some 2017, Euro 6 cars, allowed unrestricted access into ULEZs, produce NOx emissions up to 20 times the legislated test cycle limits.
  • AIR is calling on policy makers in London and across Europe to make clean air zones more effective by tackling the issue of dirty Euro 6s – using ratings such as the AIR Index – to bring air quality into legal compliance as soon as possible.
  • To learn more about the AIR Index and see a rating for your vehicle go to

25 July 2019 The latest findings from the DVSA’s ‘2018 Vehicle Emissions Testing Programme’1 highlight the threat to air quality improvements in ultra-low emission zones (ULEZs) from poor vehicle emissions from some Euro 6 cars.

Tests carried out by the DVSA on a range of popular Euro 6 vehicles identified low and high emitters in line with the results of similar tests conducted for Allow Independent Road-testing (AIR) and published in the AIR Index. The DVSA tests reveal that some fully homologated vehicles meeting the legislated laboratory tests produce up to 20 times the NOx emissions limit during the WLTP track test.

Consequently, city policy makers across Europe who are using, or plan to use, Euro 6 as the basis for city access will be unable to stop over-emitting cars adding to poor urban air quality. AIR is not aware of a single Clean Air Zone (CAZ) or ULEZ operating in Europe which has implemented a way to discriminate between clean and over-emitting Euro 6 vehicles.       

The DVSA’s tests show that during WLTP track tests the Nissan Qashqai diesel was found to be more than 17 times the legislative limit for NOx and the Renault Kadjar diesel was 13 times the same limit. Diesel versions of models within the ranges of the BMW 1-series, Hyundai Tucson, Jaguar F-Pace, Vauxhall Astra and Volvo XC60 were all found by DVSA to be multiple times higher than emission limits for the legislated test cycle. The only car tested by DVSA and found to be within the limits was the Mercedes E-class diesel.      

The AIR Index rates vehicles tested in urban conditions to the same standardised methodology providing comparable NOx emissions levels that more accurately reflect the contribution to urban air quality than existing tests performed in a laboratory. It has been created to inform and empower car buyers and city policy makers with the real facts about vehicle emissions when making choices about car purchase and usage. A simple A-E colour-coded rating, shows the difference between clean and dirty vehicles based on how much NOx comes out of a car’s tailpipe in urban driving.

For example, the diesel Nissan Qashqai tested by the DVSA has a provisional AIR Index ‘E’ rating, indicating extreme levels of NOx emissions (>600 mg/km) with the worst impact on air quality in towns and cities. The diesel Vauxhall Astra tested by the DVSA has a provisional AIR Index ‘C’ rating, indicating high levels of NOx emissions (168 – 270 mg/km) impacting air quality in towns and cities. The DVSA presented the results to car makers and invited them to improve the emissions performance of their cars. Several companies are in the process of offering solutions, but Nissan declined to do so, a decision described as ‘unacceptable’ by DVSA.

Nick Molden, Co-Founder of the AIR Index said, ‘Cities who in good faith are using or plan to use Euro 6 as the threshold for access policies will not deliver the air quality improvements expected and will not solve their breach of urban air quality in the time required. The DVSA’s latest test results confirm the importance of independent testing to provide confidence and transparency about actual emissions during on-road driving. We welcome the government’s publication of this report which aligns with the results of vehicles rated for the AIR Index, and it highlights again that not all Euro 6 cars control NOx emissions to the same degree.’

Massimo Fedeli, Operations Director and Co-Founder of the AIR Index said, ‘Car owners, policy makers and citizens in towns and cities where air quality is breaching European limits will be disappointed by both the poor results of these tests and the reaction of those car makers who refuse to take action to remedy the over-emission of NOx from these vehicles. AIR’s mission is to help reduce the negative impacts of vehicle emissions in the short and long term. We believe that only the cleanest internal combustion engine (ICE) vehicles should have free access to cities and the most effective way to determine this is through independent emissions testing. The AIR Index ratings offer cities a legal framework to improve air quality, quickly and effectively, avoiding the potential scenario of vehicle bans which would restrict mobility and penalise clean vehicles.’


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About the AIR Index

Cars rated for the AIR Index are tested according to the CWA 17379 standardised methodology which ensures that the results are independent, comparable and can be used as the basis for a legal framework for vehicle policies.

The testing is carried out on at least two cars, sourced independently from vehicle manufacturers with portable emissions testing units (PEMS) recording actual on-road driving in towns and cities.  For a result to be considered acceptable for rating in the AIR Index there must be at least five, 10 km trips completed during three separate journeys on at least two matching vehicles in line with the CEN standard. 

The results of the tests provide the basis to rate the vehicle according to the A-E, colour-coded scale.

The AIR Index website includes more than 200 results of the first tests conducted with ratings A-E, but also provides a facility to check other vehicles on the road to see if they would be allowed access (or not) to the 14 German cities which have set a NOx limit of 270 mg/km under the Federal Emissions Control Act.

Other cities across Europe are considering a similar threshold to control access and allow only the cleanest cars to enter. Car buyers should consider carefully the implication for a vehicle’s residual value, and their own mobility requirements, if it is unable to enter a town or city where emissions are controlled.

About the DVSA

The DVSA carry out driving tests, approve people to be driving instructors and MOT testers, carry out tests to make sure lorries and buses are safe to drive, carry out roadside checks on drivers and vehicles, and monitor vehicle recalls. DVSA is an executive agency, sponsored by the Department for Transport.

1 Results of the 2018 Vehicle Emissions Testing Programme were published on 22 July 2019 and the report can be downloaded from the DVSA website.

The DVSA report shows the results of WLTP track tests for the selected 2017 diesel cars (dark green bars). The NOx limit under laboratory conditions for Euro 6 diesel is 80 mg/km, which relates to an on-road ‘A’ in the AIR Index and is shown by the light green line. The chart shows just how far beyond the original homologation limits all but one of these vehicles emit during on-road use.

Sources: DVSA ‘Vehicle Market Surveillance Unit Results of the 2018 Vehicle Emissions Testing programme; AIR research

About AIR

AIR (Allow Independent Road-testing) is an independent alliance of public and private organisations, which promotes the voluntary uptake of independent on-road emissions testing.

The alliance’s key objective is to contribute to delivering a cost-effective and timely reduction in harmful vehicle emissions in urban areas, while ensuring the lowest CO2 emissions from the global vehicle fleet.

AIR seeks to empower citizens, industry and public authorities to take informed decisions on their mobility practices and policies by promoting full transparency on vehicle emission levels.

Scientific Advisory Committee

The development of the AIR Index has been led by the world’s leading academics in the fields of emissions and air quality and they make up AIR’s Scientific Advisory Committee (SAC).

  • Professor Helen ApSimon, Professor of Air Pollution Studies, Imperial College London.
  • Dr Adam Boies, Reader in the Energy Division, Department of Engineering, University of Cambridge.
  • Dan Carder, Director for Alternative Fuels, Engines and Emissions, West Virginia University.
  • Dr Claire Holman, Chair, Institute of Air Quality Management.
  • Dr Guido Lanzani, Head of Air Quality Unit, Regional Environmental Agency, Lombardy Region.
  • Dr Norbert Ligterink, Senior Research Scientist, TNO.
  • Martin Lutz, Head of Sector Air Quality Management, Berlin Senate Department for Environment, Transport and Climate Protection.
  • Dr Xavier Querol, Institute of Environmental Assessment and Water Research, Spanish Council for Scientific Research.
  • Dr Marc Stettler, Lecturer in Transport and the Environment, Centre for Transport Studies, Imperial College London.
  • Dr Martin Williams, Professor of Air Quality Research, Kings College London.

Notes on European Air Quality

The European Environment Agency provides independent information on the environment for those involved in developing, adopting, implementing and evaluating environmental policy and the general public. In its latest report, published in April 2018, updated in November 2018, the European Environment Agency stated that for particles and nitrogen dioxide, because of the widespread exceedance levels in urban areas, it is unlikely that the air quality standards for these pollutants will be met by 2020 across the EU.

See more at: https://www.eea.europa.eu/airs/2018/environment-and-health/outdoor-air-quality-urban-areas 

Ultra-Low Emissions Zone (ULEZ)

The existing ULEZ policy in London is based on Euro emissions standards (minimum Euro 6 for diesel and Euro 4 for petrol) for penalty-free access, but unfortunately independent emissions testing reveals that up to half of Euro 6 diesel cars produce much higher levels of NOx from the tailpipe during city driving than during homologation laboratory tests. This means that the current ULEZ policy is inadvertently allowing in over-emitting vehicles which are contributing to the problem of poor air quality.

AIR proposes that ULEZ policy makers in London and other cities developing their own solutions should use the independent AIR Index emissions rating for vehicles, in conjunction with Euro standards to provide the most effective reduction of harmful vehicle emissions.

If the AIR Index was used as the basis for access, this would increase the effectiveness of the ULEZ and clean up London’s air more effectively.

The AIR Index also provides ULEZ policy makers with a fair way to control access for vehicles of all ages, because it is based on the actual emissions produced, meaning that an older, lower emitting vehicle can still travel in the zone, whilst a newer more polluting vehicle may not. This ensures that access to towns and cities is not restricted only to people able to afford newer, and typically more expensive vehicles.

Find out more about ULEZ and AIR Index.


DVSA Report Confirms High Risk of Low Emission one Failures From Over-Emitting Euro 6 Vehicles

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