What’s the EURO 6 standard? (2024)

EURO 6 – the latest emission standard – reduced the limits for the amount of nitrogen
oxides emitted by cars with the diesel engines. The permitted average level of CO2
emission for particular vehicle manufacturers was also reduced, but most importantly,
they manner of measuring the emission was changed.

Since when has the EURO 6 standard been functioning?

The European emission standard known as EURO 6 was approved in 2014, and it concerns
passenger cars registered since September 2015. The sixth version of the standard had even
more editions than EURO 5 – the first EURO 6b was followed by EURO 6c, after which
EURO 6d-Temp was released, and finally the proper EURO 6d was introduced.
By the first registration date of new passenger cars, EURO 6b enforced since September
2015, EURO 6c since September 2018, EURO 6d-Temp since September 2019, and EURO
6d – since January 2021.

Types of the EURO 6 standards

There are three modifications of this standard – yet, unlike the transitions from EURO 4 to
EURO 5, or from EURO 5 to EURO 6 – these editions did not introduce tightening of the
requirements for particular emission limits, but they presented the manners of measurement,
which would allow getting the most reliable and as realistic as possible results.

The EURO 6b standard

Considering the standard released immediately after EURO 5, EURO 6b and the gasoline
engines do not differ a lot. Actually the only modification, when it comes to the values solely,
is the new format of particulate matter emission measurement. When it comes to the cars
equipped with the diesel engines, this format was already applied in EURO 5b. For the so-
called diesels, the permitted amount of emitted nitrogen oxides (NOx) was reduced.
So what is it about – and why the latest standard couldn’t be just another edition of EURO 5?
Here are a few things. First of all, it’s about making the results of the tests of compatibility
with the EURO standard more realistic and reducing the permitted deviations from the
type-approval declarations. This is one thing. Another thing is the average emission
measured for all the models available in the offer of a given manufacturer – and such limit is
gradually reduced.

The EURO 6c standard

The introduction of the EURO 6c standard did not result from the tightening of the
regulations, but because the New European Driving Cycle (NEDC) stopped being… new. It
was an obsolete – last updated in 1997 – way of measuring pollution emission.
It was replaced with the Worldwide Harmonized Light Vehicle Test Prodcedure (WLTP), a
new procedure allowing better estimation of both pollution emission and the level of fuel
consumption. The replacement of NEDC by WLTP was symbolically marked with an update
– similarly to the EURO 6b standard, which evolved into 6c.

The EURO 6d-Temp standard

The 6d-Temp (temporary) edition, is a EURO standard update which was supposed to be
temporary only.

The introduction of 6d-Temp was a kind
of a response to the high- or low-profile cases of manufacturers of new cars manipulating the
tests, showing results better than could be achieved in reality, in the traffic conditions.
The sixth EURO standard, whether in the temporary or final version, is also labeled as ISC-
FCM. It means that the matter whether or not cars meet the new requirements is established
based on the monitoring equipment reading, which the vehicle manufacturers are obliged to
equip their vehicles with. In other words, it is supposed to prevent the gap between the theory
and the practice – to guarantee that new cars meet the European emission standard, not only
during tests, but also during the regular use (RDE – Regular Driving Emissions).

The EURO 6d standard

EURO 6d is the latest so far, updated working European emission standard. It concerns the
manufacturers so that in their model range available in the European Union, the average
carbon dioxide (CO2) emission does not exceed 95 g/km. Slightly different values are
applied for brands offering smaller, mostly city cars, and slightly higher values for those
offering biggest and heavier cars.

When the 6d-Temp standard was relevant, the permitted variance difference between the
laboratory and the road tests was up to 2.1. It means that e.g. nitrogen oxides emission
could’ve been in reality over twice higher than a given manufacturer stated on the basis of the
laboratory tests results. Since the beginning of 2011, this coefficient has been reduced to 1.43,
but this is not the end – the ultimate goal is that the laboratory test results correspond to the
road test results.

The consequences of the EURO 6d standard introduction

The entry into force of the EURO 6d standard was the most feared by the dealers, who didn’t really know what to do with the vehicles manufactures earlier and not adjusted to the new standard.

One of the obstacles that hindered the typical “model of the year sales” was, i.a. the pandemic, as a result of which many people, who until then had been willing to spend money, started to look for saving opportunities.

Their tendency for inhibiting spending money forced some dealers to register – before 1st January 2021 – unsold cars on themselves and then offer them for sale as used ones (although de facto they were still new).

What is the maximum emission value for this standard?

The values presented below concern tests conducted in laboratory conditions – it is significant
in the case of e.g. nitrogen oxides. As it has been mentioned above, the 6d-Temp standard
obliged the passenger car manufacturers to implement road tests, so that the vehicles were
subjected to the analysis as close to reality as possible.

The EURO 6 emission standard requirements for cars with gasoline engines:

• CO: 1 g/km
• HC: 0.1 g/km
• NOx: 0.06 g/km
• VOC: 0.068 g/km
• PM: 0.0045 g/km (for vehicles with the gasoline direct injection)
• Particulate matter: 6.0×10^11/km (6.0×10^12 for the first three years of the EURO 6
  standard validity)

Along with the introduction of the new EURO standard for the passenger cars, there has been
introduced also a new way of measuring the particulate matter emission, already applied
before for the diesel engines.

The EURO 6 emission standard requirements for cars with diesel engines:

• CO: 0.5 g/km
• NOx: 0.08 g/km
• HC+NOx: 0.17 g/km
• PM: 0.0045 g/km
• Particulate matter: 6.0×10^11

Considering the diesel engines, the permitted nitrogen oxides emission was substantially
reduced.

The EURO 6 standard and the clean transport zone

The dissemination of clean transport zones is just a matter of time. It results from the
necessity of adjustment to the regulations enforced in the European Union, and also from the
care about the air quality – especially in the city centres, where its quality is the worst.

The legislator wants that the cars which meet the EURO 6 requirements can enter clean
transport zones at least until 2035. Will it be this way in reality – time will tell. For sure,
this period of time will not be reduced. Its extension is more probable, due to the already
existing difficulties with the arrangement and refinement of the EURO 7 standard regulations.

Which cars does the EURO 6 standard concern?

The EURO 6 regulations concern light passenger cars (the M category) and utility cars
(the N1 and N2 categories) both with the gasoline, as well as the diesel engines.

Considering motorcycles and other two- and three-wheel vehicles, the latest, currently
enforced regulation is the EURO V standard, introduced in 2020.
For trucks and buses other regulations are applied, due to a different way of measuring the
emission – the pollution is measured not in grams per kilometer, but in grams per kilowatt-
hour.

The future of the EURO 6 standard

The cars meeting the requirements of the EURO 6 standard will be allowed to enter the clean
transport zones until 2035 (five years longer than the cars meeting the requirements of EURO
5). Until then, for sure the next standard will have been released, the EURO 7 standard. Just
like in the case of each previous standard being introduced there was certain concern raised –
whether among the manufacturers or drivers of the older passenger cars – also in this case, the
scare was replaced with common panic.

How exactly the new standard will look like, whether it will indicate the definite end of
diesels and the gasoline engines, and when it will be enforced – it is an unknown so far…
although experts have no doubts concerning certain aspects of it.

And although the requirements of the EURO 6 were already tremendously strict, and the cars
meeting them harm the environment substantially less compared to the ones manufactured
just a few years earlier, the long-term goal of the European Union is to reduce the emission to
zero. And this means, that sooner or later the gasoline engines and the cars with the diesel
engines will have to be replaced – regardless of which emission standards these cars
meet. The future is electric, there’s no space for the emission.