Euro 6 compliance and emission standards

Here in the UK, we’ve had rules and regulations for car exhaust emissions since the 1970s. But growing concerns over health and environmental risks have seen the laws become much tougher. Euro 6 emission rules are now in full force.

Whatever your personal views on pollution and climate change, the impact of the stricter measures is unavoidable. With the London ULEZ scheme and Birmingham Clear Air Zone (aka the CAZ) now in effect, as a UK driver entering major cities at any point, having a handle on Euro 6 compliance is essential.

Euro 6 compliance and emission standards
Emissions regulations start in the 1970’s and have become ever stricter.

Fortunately, our ultimate guide to Euro 6 Emission Standards will help you make the best of the situation, whether you’re about to buy a new Euro 6 vehicle or sell a car, want to save money in the future, or planning a road trip.

Euro 6 Emissions Standards and compliance explained:

  1. What are the Euro 6 standards?
  2. How will the Euro 6 standards affect me?
  3. Is my car Euro 6 compliant?
  4. Euro 6 car check
  5. Euro 6 diesel cars explained
  6. Euro 6 conversions

What are the Euro 6 Emission standards?

Petrol and diesel combustion engines inevitably produce emissions as part of their normal operation. The Euro 6 standards were introduced within the EU to try and ensure vehicle manufacturers keep harmful emissions below specific limits.

Euro 6 Emissions Standards want to reduce pollution
Euro 6 Emissions Standards aim to cut traffic pollution

Only aeroplanes and seagoing ships are exempt from testing. Everything else, from scooters to trucks, has a set of standards to meet before they can be Euro 6 compliant and sold within the EU.

That includes both petrol and diesel cars. The rules cover nitrogen oxide (NOx), carbon monoxide (CO), hydrocarbons (THC and NMHC), and particulate matter (PM). The last of which is the soot you can see emanating from the rear of diesel vehicles.

Limits are different for petrol and diesel engines:

  • Euro 6 Diesel Emissions Standards (grammes per kilometre): 0.50 CO, 0.080 NOx, 0.005 PM
  • Euro 6 Petrol Emissions Standards (grammes per kilometre): 1.0 CO, 0.060 NOx, 0,005 PM

To confuse things more, changes have been made to the testing procedure following the diesel emissions scandal. The standard was originally applied to cars type approved in September 2014 and first registered on the road in September 2015.

Originally the testing was purely carried out in laboratory conditions (known as WLTP), and the testing methods were updated to create a new Euro 6c designation effective from September 1st, 2017.

A new test on public roads to simulate Real Driving Emissions (RDE) has now been introduced. But whether your car is Euro 6, Euro 6c, Euro 6d-TEMP, or Euro 6d, the emission amounts are the same. The differences are purely about testing and how much discrepancy is allowed between the lab figures and those from testing on real roads. Euro 6-TEMP allows the figures to deviate by 110%, but for full Euro 6d approval, the deviation allowed will be 43%.

Most new cars produced since the end of 2017 are Euro 6d-TEMP compliant, and some manufacturers such as Jaguar and Mercedes already exceed the full Euro 6d regulations.

How did the Emission Standards come into being?

The first rules covering air pollution from motor vehicles were introduced on 20th March, 1970. The Council Directive 70/220/EEC introduced tests for carbon monoxide, and hydrocarbons.

All of the later Euro standards are amendments that have introduced tougher limits and testing. They’re listed below, alongside the date they applied for a vehicle first registration:

  • Euro 1: January 1993
  • Euro 2: January 1997
  • Euro 3: January 2001
  • Euro 4: January 2006
  • Euro 5: January 2011
  • Euro 6: September 2015
  • Euro 6d-TEMP: September 2019
  • Euro 6d: January 2021

The purpose of these measures was to combat the risks to human health and the environment due to vehicle pollution. For example, road transport accounted for 34% of all UK NOx emissions in 2015.

Naturally, the effect is greater in congested urban cities. The emissions contribute to smog, acid rain, and other air pollution. Carbon monoxide also creates pollution and is a leading contributor to climate change.

Poor air quality and pollution in congested urban areas has led to stricter standards
Pollution in congested urban areas has led to stricter standards

The Society of Motor Manufacturers and Traders (SMMT) claim that it would take 50 new cars today to produce the same amount of pollutant emissions as one vehicle built in the 1970s.

An even stricter Euro 7 standard will be unveiled in the next few years. Partly this will continue the progress towards lower emissions, but it will also hopefully reduce some of the confusion around the various Euro 6 testing standards and ongoing compliance.

This is likely to appear soon, as countries including the UK plan to stop the sale of new petrol and diesel cars in the next two decades.

How will the Euro 6 emission standards affect me?

There are a number of ways the Euro 6 emission standards affect the typical car owner. The first is the amount you pay for car tax. Vehicle tax for cars registered on or after 1st March 2001 is based on CO2 emissions and fuel type.

Diesel cars that meet the Real Driving Emissions 2 (RDE2) standards for full Euro 6d compliance pay substantially less in tax for the first registration year. The difference can vary from £15 up to £535, which is a significant amount.

The other most noticeable effect is if you drive into major UK and European cities. In the UK, the London Ultra Low Emissions Zone (ULEZ) currently affects pre-Euro 6 diesels and pre-Euro 4 petrol cars with a standard daily charge of £12.50. You can check your car for ULEZ compliance with the our ULEZ checker.

ULEZ limits access for old, high-polluting cars.
The Ultra Low Emissions Zone in London will limit access for older vehicles

Similar schemes are also in operation across most major European countries. And while some cities focus purely on Heavy Goods vehicles, many also include passenger cars.

The regulations are often similar to London, but some do have more stringent rules. For example, from July 4th, 2019, cars must be at least Euro 2 to enter Paris between 8am-8pm. But the plan is to increase the minimum standard until all petrol and diesel vans will be banned from Paris in 2030.

If you’re planning a European road trip, it’s increasingly important to check the relevant city restrictions before travelling in an older vehicle. You can look by country or city on the official EU Urban Access Regulations website.

Diesel cars use a process called Selective Catalytic Reduction, or AdBlue, to lower the amount of oxides. This injects a solution into the exhaust gases which does need refilling every few thousand miles, although it’s relatively cheap at around £1.50 per litre for a dealer to top up your system

Although the UK is still negotiating an exit from the European Union, the emissions standards are unlikely to be changed. Not only will car manufacturers continue to build to the compliance specifications of the largest available market, but many non-European countries are also slowly adopting the same emissions standards.

Ultimately this all factors into the used car market. If you own an older car and you live in a commuter area, some car buyers may be put off. At the moment, other cities are still considering whether to implement more low emission zones in the UK, so the effect on used prices is relatively limited.

But if you have the option to choose a Euro 6 standard car versus a slightly older model, it may well be a better investment for the future. We’ve also written a specific guide if you’re still wondering whether to buy or sell a diesel car.

Is my car Euro 6 compliant?

All new cars registered from September 1st, 2015 should be Euro 6 compliant. And from September 2018, the Euro Emission Standard of your car can be found on the V5C document.

If you don’t have a logbook that tells you the emissions rating for your car, it’s worth doing a vehicle-specific check. Not only could your car have had a delay between production and registration, but even different trim and specifications of a specific car model can vary in emissions ratings.

The good news is that you may be pleasantly surprised. Some car manufacturers have been producing Euro 6 compliant cars since as early as 2012. With earlier cars, particularly diesels, it tends to be the environmentally-focused ranges that qualify.

For instance BMWs with the optional ‘BluePerformance’ pack, or ‘BlueHDi’ Citroen’s and Peugeot’s tend to be compliant with the regulations. Other brands with a wide range of earlier Euro 6 models include Volvo, Mazda, Audi, and Mercedes.

You can check either by contacting your manufacturer or using an online checking tool.

Euro 6 car check?

A number of services exist for checking the emissions rating of your car and therefore its Euro 6 compliance. At the same time, you can also find out tax information and cost.

The Vehicle Certification Agency offer one of the services which covers all new cars currently on sale in the UK, and used cars that were first registered on or after March 1st, 2001.

You’ll need to know the month and year in which the car was first registered.

Then you can select the type of fuel, transmission, manufacturer, model and engine description.

To see the actual Euro Emissions Standard, click on the Description for more details, and you’ll find all the information under ‘Further Details’.

A variety of other services exist, including one from UK Government, and the HPI Euro Emission Standards Checker.

Euro 6 diesel cars explained

As mentioned above, to meet the Euro 6 Emission Standards, many diesel cars use a Selective Catalytic Reduction, or AdBlue process to lower the number of oxides emitted.

This system needs to be regularly refilled, and mileages vary between cars and owners. Many drivers will find it coincides with their annual service. But if you regularly cover long distances, it may be a more frequent occurrence.

Diesel cars have been fitted with extra technology
Diesel cars have been fitted with extra technology to meet Euro 6 regulations

For example, Jaguar quote the range at one litre used for between 400-550 miles depending on your model of car and driving style. This gives you 5,000-9,400 miles between refills (again, depending on the Jaguar you own).

When it comes to choosing to buy a diesel car, most models registered since September 2015 will be compliant.

Manufacturers with earlier examples of Euro 6 diesel cars include:

  • Audi
  • BMW
  • Citroen
  • Mazda
  • Mercedes
  • Mini
  • Peugeot
  • Vauxhall
  • Volkswagen
  • Volvo

Euro 6 conversion – how to convert your car to meet the Euro 6 standards

If you own an older car that isn’t Euro 6 compliant, you may be wondering if you can convert it to meet the latest standards.

For petrol cars, this isn’t really a possibility. The range of technology involved in meeting Euro 6 emissions standards is pretty complex and integrated into the design of the car. So it wouldn’t make financial sense compared to buying a car already built with those regulations in mind.

You could possibly switch to electric or Liquid Petroleum Gas. But LPG conversions cost as much as £2,000, and you only save £10 per year on road tax as an alternatively-fuelled car.

There are substantial savings on fuel costs, but LPG has specific rules and regulations regarding usage. Meanwhile converting a car to electric power can cost from £12,000 to £20,000 if you hire a specialist company, so it would have to be a pretty special car to justify the investment.

Diesel vehicles can potentially be converted to meet Euro 6 emission standards. Because a large part of the process to reduce harmful gases takes place in the exhaust system, it’s a more viable option.

Upgrading an existing car to Euro 6 is very expensive
Converting older vehicles to Euro 6 only really makes sense for commercial vehicles

But while you could potentially upgrade any diesel, it doesn’t make sense for most motorists. It will add weight, require substantial space around the exhaust system, and the cost is likely to outweigh the benefit.

That’s why most conversion services and products are aimed at the commercial market, particularly larger and more expensive vehicles. SCR systems range from around £1,200 to £3,000.

There’s also an issue that there’s no current certification for retrofit systems. So it’s difficult to know whether or not your work will result in a Euro 6 compliant car. Or whether the work will be recognised by authorities operating the low emissions zones in the UK and Europe.

In Germany, the transport ministry has released guides for getting regulatory approval on retrofitted exhaust systems, with Volkswagen and Daimler offering to cover some of the costs. But in the UK, the focus so far has been on upgrading public vehicles including buses and black cabs.

Ultimately if you’re considering converting an older diesel to meet the Euro 6 emission standards, it’s probably worth waiting if possible. As it becomes a more common need, the process should become cheaper and easier. But at the moment, it’s hard to justify on practical and financial grounds.

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