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Euro 6 Emissions Standards Guide

Euro 6 is the latest in a series of ratings to reduce harmful pollutants from vehicle exhausts. Read our guide for all you need to know about Euro 6 and Euro 6d cars.

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Euro 6 emissions standards

When car shopping, it’s no longer just a case of selecting the right colour, trim and specification. You also need to consider the vehicle emission rating – and the one you need is Euro 6.

Since 1992, the European Union has enforced increasingly strict limits on vehicle emissions, known as Euro emissions standards.

Euro 6 was introduced on 1 September 2015 and is the latest in a series of ratings that help reduce the pollutants released from new petrol and diesel vehicles. This also includes hybrid cars as they use a petrol or diesel engine under the bonnet with their electrical elements.

The emissions standards are designed to become more stringent over time and define acceptable limits for the exhaust emissions of new light duty vehicles sold in EU and EEA (European Economic Area) member states.

Whether your vehicle is a Euro 6 diesel or a Euro 1 petrol, knowing your car’s rating is increasingly important as more fines and levies are being introduced for older cars, especially those that run on diesel fuel, as well as Clean Air Zones (CAZ) and Ultra Low Emission Zones (ULEZ) in cities and towns.

What is Euro 6?

Euro 6 is the sixth rating of the European Union directive to reduce harmful pollutants from vehicle exhausts, including:

  • Nitrogen oxide (NOx)
  • Carbon monoxide (CO)
  • Hydrocarbons (HC)
  • Particulate matter (PM)

It’s the name given to a set of limits for harmful exhaust emissions produced by any vehicle powered by petrol or diesel engines. New type approvals from September 2014 and all mass-produced cars sold after September 2015 must meet these emissions standards.

However, the way that emissions are tested has changed to become more realistic and has led to the latest Euro 6d standard being introduced. We discuss this in more detail below.

The Euro 6 emissions standard gained increased potency in 2019 as it consolidated the criteria under which new ultra-low emission zones (ULEZ) and clean air zones (CAZ) are currently enforced.

Any diesel vehicle that doesn’t meet the Euro 6 standards will be subject to a daily charge of up to £12.50 upon entry to these zones, in order to help improve air quality.

Are the Euro 6 emissions standards the same for petrol and diesel cars?

Euro 6 regulations set different emission standards for petrol and diesel vehicles that are reflective of the different types of pollutants the two fuels produce. For example, diesel produces particulate matter (PM), which is basically soot, and has led to the introduction of diesel particulate filters (DPFs).

Diesel – the NOx limit has dropped significantly to 80mg/km compared to the 180mg/km limit required under the Euro 5 emissions standard.

AdBlue is also required in diesel cars and helps vehicles meet the Euro 6 standards. It’s injected into the engine’s gas exhaust system which results in a chemical reaction, converting NOx into harmless water vapour and nitrogen.

Petrol – the NOx limit is 60mg/km and remains unchanged.

The Euro 6 standards that vehicle engines must meet are separate to fuel specifications which also set strict limits on factors such as sulphur levels.

How are new cars tested for emissions?

For a car to be sold in Europe, it must adhere to Euro 6 emissions standards on official tests.

Initially, Euro 6 cars were tested for emissions and fuel economy in a laboratory on a rolling road. These tests were infamously unrealistic compared with real-life driving and could be easily manipulated, such as in the 2015 emissions scandal.

To ensure these tests accurately represent real-world driving, World harmonised Light duty Testing Protocol (WLTP) tests were launched in September 2018 to replace old NEDC tests.

All cars are WLTP tested to ensure emissions are reflected more closely to fuel economy and emissions when actually driving. This includes an additional test known as real-world driving emissions (RDE) which was introduced in September 2017 to help ensure cars meet limits in a much wider range of driving conditions.

RDE testing in more detail

RDE testing is conducted on the road rather than in a lab and uses a portable emissions measurement system to accurately record emissions. Using a highly controlled environment that’s overseen by Government agencies, it measures the ambient temperature, vehicle fluid levels and tyre pressures to maintain consistency between tests of different models.

Testing cars in the same conditions helps ensure the emissions figures can be compared directly when looking at specs between cars. Cars are randomly selected by the legislative body to avoid manufactures ‘tweaking’ or preparing models for the testing.

Euro 6d emission standards

From January 2022, all new cars must pass the real-world test with lower limits (RDE2), effectively equalling the levels in the laboratory test. This standard is also known as Euro 6d and is expected to result in a generation of much cleaner new diesel cars.

These new adhering vehicles will be cheaper to tax, particularly for business users as they will not be subject to the 4% company car tax surcharge that adheres to all other diesel vehicles. That could see savings of £500 a year for a £30,000 car.

RDE was introduced in two steps

RDE step 1 – relates to new type approvals from 1 September 2017 and all new registrations from 1 September 2019.

  • For RDE1 a NOx conformity factor of 2.1 will apply meaning that NOx emissions in the RDE1 test can be up to 2.1 times the Euro 6 laboratory limit of 80mg/km
  • Cars type-approved during this period will be described as meeting Euro 6d-temp

RDE step 2 – applies to new type approvals from 1 January 2020 and all new registrations from 1 January 2021.

  • For RDE2 the NOx conformity factor is 1.0 but with an error margin of 0.5 meaning that NOx emissions in the RDE2 test can be up to 1.5 times the Euro 6 laboratory limit of 80mg/km
  • Cars type-approved during this period will be described as meeting Euro 6d
Emissions standardDetailsEmission zone and tax benefits
Euro 4Mandatory for all types of new cars from January 2006Minimum standard for petrol cars to be exempt from London ULEZ and Birmingham CAZ
Euro 5Mandatory for all types of new cars from January 2011 
Euro 6Mandatory for all types of new cars from September 2015Minimum standard for diesel cars to be exempt from ULAZ and CAZ
Euro 6d tempNew cars must meet real-world testing limits from September 2019 
Euro 6dTougher real-world testing limits are mandatory for new cars from January 2022Diesel cars exempt from company car and car tax surcharges

Benefits of a Euro 6 car

Emission-related charges – Driving a Euro 6 standards car means you won’t have to pay the high charges when entering Clean Air Zones or Ultra-Low Emission Zones like you would when driving a non-compliant vehicle. Therefore, getting a cleaner car can help you save a lot of money!

Company car tax – To make the biggest savings, it’s best to opt for cars that are at least Euro 6d compliant which will also help cut your emissions.

Car tax (VED) – Although car CO2 emission limits aren’t covered by Euro 6, compliant cars will usually have lower emissions. Therefore, the better subcategory of Euro 6 the car meets, the lower your emissions will likely be and the less it will cost you in VED (vehicle excise duty or road tax).

The Euro 1 to Euro 6 standards timeline

Euro 1 (EC93) standards came into law in 1993 which ensured diesel cars emitted no more than 780mg/km of nitrogen oxide, and the maximum for petrol engines was 490mg/km. This also saw catalytic converters become compulsory on new cars, effectively standardising fuel injection and reducing carbon monoxide (CO) emissions. Since then, there have been a series of successive standard revisions.

Euro 2 (EC96) was introduced in 1997 which dropped NOx levels to 730mg/km, followed by Euro 3 (EC2000) standards in 2001 which reduced levels to 500mg/km. Euro 4 (EC2005) standards then came into effect in 2006 to reduce NOx levels to 250mg/km and again to 180mg/km in 2011 under Euro 5 standards.

Until Euro 6 (80mg/km NOx in diesel models and 60mg/km in petrol vehicles) the maximum amount of NOx emitted by diesel vehicles was far above the level permitted for petrol vehicles.

Why do I need to know my vehicle’s Euro emission standard?

In 2018, the government announced the Road to Zero strategy to support the move to zero emission road transport which includes the ban of the sale of new petrol and diesel cars by 2040 and a complete ban by 2050.

As part of this initiative, an increasing number of UK authorities are implementing low-emission zones to help further reduce air pollution. Knowing your car’s Euro emission standard is essential if you intend to travel to or through these ULEZ zones; penalty charge notices may be applied if you don’t follow the ULEZ’s rules, costing up to £160 per day.

Is my car Euro 6 compliant?

The dates when the standards were introduced will help you determine which emissions standard your car confirms to. The implementation date for Euro 6 was September 2014 (new approvals) and September 2015 (most new registrations). You can find this information on your V5C document, which details your ownership of the car and other important information.

See the below tables to help you determine what emissions standard your car is, and what that classification means in terms of the actual emissions produced. Every vehicle sold up to a year after the dates below should conform to the appropriate standards. Nevertheless, it’s always best to check with your car’s manufacturer for complete clarity as some cars bought after the implementation date may still have the previous Euro standard.

If your vehicle pre-dates Euro emissions, then you may be banned from entering certain cities and towns.

Euro emissions standards for passenger cars using diesel

Euro standardDateCO mg/kmNOx mg/kmPM mg/km
Euro 1July 19932.720.970.14
Euro 2January 199710.70.08
Euro 3January 20010.640.50.05
Euro 4January 20060.50.250.025
Euro 5aSeptember 20110.50.180.005
Euro 6September 20150.50.080.005

Euro emissions standards for passenger cars using petrol

Euro standardDateCO mg/kmNOx mg/kmPM mg/km
Euro 1January 19932.720.97n/a
Euro 2January 19972.20.5n/a
Euro 3January 20012.30.15n/a
Euro 4January 200610.08n/a
Euro 5September 201110.060.005
Euro 6September 201510.060.005

Euro 6 standards for vans

Emissions standardDateCO mg/kmNOx mg/kmPM mg/km
Euro 1October 19942.72n/a0.14
Euro 2October 19971n/a0.08
Euro 3January 20010.640.50.05
Euro 4January 20060.50.250.025
Euro 5aJanuary 20110.50.180.005
Euro 5bJanuary 20130.50.180.0045
Euro 6bSeptember 20150.50.080.0045
Euro 6cSeptember 20180.50.080.0045
Euro 6d-TempSeptember 20190.50.080.0045
Euro 6dJanuary 20210.50.080.004

Does my car’s Euro standard affect my MOT?

In May 2018, new rules were introduced for MOT testing to include stricter requirements surrounding emissions. All cars fitted with a diesel particulate filter (DPF), which is a requirement for all Euro 6 and 6 diesels (6d), that produce visible smoke of any colour during testing will give a major fault which is an automatic fail.

Will Brexit change Euro 6 emissions standards?

Euro 6 standards are compulsory for all new diesel vehicles. Regardless of what Brexit means, since 1 September 2016, all UK fleets have had to comply.

Brexit appears unlikely to make a difference to UK energy policy because Britain’s own unilateral Climate Change Act imposes even stricter requirements than the EU for reducing emissions. The UK must reduce carbon emissions by 90% on 1990 levels by 2050.

Though air quality targets technically remain within UK law due to being protected through Air Quality Standards Regulation, the EU is no longer be able to enforce them and the UK is therefore free to abolish the laws.

But while there is some concern around leaving the EU with regards to all the hard work that has been done to improve air quality being lost, the likelihood is extremely low.

When will Euro 7 standards come into force?

A date for the introduction of Euro 7 standards is yet to be set, although it’s expected that Euro 7 will be the final Euro emission standard before all cars become ‘zero emission’.

Possibilities for Euro 7

Option 1 – would see “a narrow revision of Euro 6” and a streamlining of current regulations.

Option 2 – would comprise stricter CO2 and NOx limits, in addition to new tests and limits for “non-CO2 greenhouse gas emissions.”

Option 3 – in addition to option 1 and 2 changes, cars would automatically carry out “real-world emission monitoring over the entire lifetime of a vehicle”. This would “ensure compliance, robustness against tampering, and enforcement over the entire lifetime of the vehicle”. This data would be collected through onboard monitoring to support market surveillance and in-service conformity testing.

Finalised proposals for Euro 7 are set to be presented to the European parliament at the end of 2021 and will likely come into force around 2025.

The UK’s exit from the EU means the EU will have no power to enforce the uptake of Euro 7 regulations. However, policymakers are clear that “imported vehicles would not be treated differently to domestic ones” meaning any cars built in the UK and exported to the EU would have to adhere to the regulations.

Looking to learn more about Euro 6 standards? Crown Oil is a national diesel supplier with a wealth of experience in emissions standards. Call our team of experts on 0330 123 1444 today.

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