The EURO 5 standard – what should you know about it?

25 July 2022

Although not everybody is fond of them, the EURO standards – limiting i.a. nitrogen oxides and particulate matter emission – have been a necessity. It is these regulations that forced the car manufacturers to find better and more ecological solutions. What has the EURO 5 standard introduced?


Since when has the EURO 5 standard been functioning?

The first emission standards – then still referred to as the R49 Regulation – were introduced already in the 80s of the 20th century. However, a lot has changed since then. Within the territory of the European Union and the European Economic Area subsequent, more and more rigid standards were being introduced, with the EURO 5 standard being one of them, once again modifying the permissible particulate matter, nitrogen oxides, carbon monoxides and hydrocarbons emission limits.

Its principles were approved already in September 2009, but another year and a half was required for the so-called vacatio legis. The final date for enforcing the regulation was on 1st January 2011 for cars with the gasoline and diesel engines. At the beginning of January 2013, the EURO emission standard was updated into the so-called EURO 5b.



For motorcycles and other two- and three-wheel vehicles, the EURO V standard – written using the Roman numeral for differentiation – is valid since 2020.


If you’d like to learn more about other – previous and current – particulate matter and other harmful substances emission regulations, take a look at our collective article devoted to the EURO standards.


What is the maximum emission value for this standard?

The EURO 5 standard determines various permitted emission values and the contained particulate matter, carbon monoxide and nitrogen oxides for cars with gasoline and diesel engines, as well as for the motorcycles. It forced the car manufacturers to experiment in order to find new solutions – such as discharging part of the emission from the exhaust system back to the combustion chamber, or starting to use the SCR catalysts and using additives to the fuel.


The EURO 5 emission standard limits 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: 0.005 g/km (for vehicles with the gasoline direct injection)

In terms of the permitted carbon monoxide and hydrocarbons emission for cars with gasoline engines, there are no differences between the EURO 4 and 5 standards. However, the nitrogen oxides emission limits were reduced. The volatile organic compounds (VOC) emission started to be verified, and for the first time the case of particulate matter in the gasoline engines was inspected.


The EURO 5 emission standard limits for cars with diesel engines:

  • CO: 0.5 g/km
  • NOx: 0.18 g/km
  • HC+NOx: 0.23 g/km
  • PM: 0.005 g/km
  • Particulate matter: 6.0×10^11/km (measured this way since January 2013)

The permitted limits for carbon monoxide emission in EURO 5 remained unchanged. However, the maximum nitrogen oxides emission along with the total value of nitrogen oxides and hydrocarbons were reduced. A substantial – by fivefold – reduction of particulate matter emission was applied. Since 2013 and the 5b standard, they are measured also in the quantitative manner – practically no car without the particular matter filter can meet the emission criteria any longer.


For motorcycles and other two- and three-wheel vehicles:

  • CO: 1.0 g/km
  • HC: 0.1 g/km
  • NOx: 0.06 g/km
  • PM: 0.0045 g/km
  • NMHC: 0.068 g/km



When introducing the EURO V standard for motorcycles, a new category was included – non-methane hydrocarbons (NMHC) emission.


The EURO 5 standard and the clean transport zone

The clean transport zones (SCT) are supposed to be a solution for the growing majority of the pollution – i.a. particulate matter, but also other substances – accumulating especially in the city centres, where the air movement is especially limited. The entry ban for cars not meeting a specific combustion standard is aimed at limiting the emission originating from transportation, and as the result, improve the air quality. Therefore, the EURO 5 standard was a step forward to this goal.

As it is explained in the article concerning the clean transport zones, entering the SCTs is gradually limited. Until 2025, the so-called green zones will be available for cars meeting the requirements of EURO4. Vehicles meeting the requirements of the EURO 5 standard will be allowed to enter the clean transport zones until 2030.

So – formally – there’s no need to hurry resigning from the traditional fuel and the combustion engines which meet the EURO 5 standard criteria, although, considering the harmful substances emission and the good of the environment, the faster the electric engine displaces the combustion one, the better it is (of course, on condition that the energy used to power it does not originate from the fossil fuel combustion).


Which cars does the EURO 5 standard concern?

The EURO 4 standard concerned not only passenger cars and motorcycles, but also buses, trucks and other vehicles. In the case of EURO 5, there has been certain distinction. The “fifth version” of the popular standard embraces:

  • light passenger and utility cars (in accordance with the Regulation no. 715/2007),
  • two- and three-wheel vehicles (following the Regulation no. 168/2013).

The EURO 5 standard is therefore applied to passenger cars (the M category) with diesel and gasoline engines, motorcycles and three-wheel vehicles (the L category), and light utility vehicles (the N1 and N2 categories). For truck and buses separate regulations were prepared, i.a. due to the fact that the manner of presenting the harmful substances emission changed (not in grams per kilometer, as it was until then, but in grams per kilowatt-hour).


What is SCR?

Increasingly more rigid new standards forced the manufacturers to look for advanced and ecological solutions. One of the examples of this is introducing the SCR system to vehicles with the diesel engines. The role of the SCR, selective catalytic reduction, is to limit the harmful substances emission, in this case nitrogen oxides.

How does the selective catalytic reduction work? The AdBlue fluid is injected under pressure to the initial section of the exhaust system. The urea it contains, under the action of high temperature, turns into ammoniac, which in the presence of nitrogen oxides, breaks them down into nitrogen and water – products completely safe for the environment. When in comes to the diesels meeting the EURO 5 criteria, the SCR catalysts were not yet used on a daily basis. The spread of these catalysts was accelerated by the EURO6 standard, which allows substantially lower share of NOx in emission.

This piece of technology is not free from flaws – and a vehicle equipped with the SCR catalysts might cause problems, especially in winter (the AdBlue fluid freezes already at -11°C). Any abnormalities in the system performance might result in the necessity of having expensive repairs done, and also the engines performance might be disrupted.


What is EGR?

Another way – aside from SCR and the particulate matter filters – to improve the emission parameters used by the vehicle  manufacturers is the EGR system (Exhaust Gas Retention), which one of the elements is the well-known to the drivers EGR valve. Installed both in the gasoline engines (with the spark ignition) and in the diesel engines – so regardless of the type the fuel used. Its role is to make a part of the emission go back to the combustion chamber, instead of the atmosphere.

The EGR valves direct a part of the emission – through a special radiator – back to the inlet system. Its role is NOTburning down the emission” but reducing the temperature and slowing down and calming the combustion, which, as the result, reduces the harmful substances emission.

There’s no lack of drives ready to deprive the engine of the EGR valve, but it not recommended (nor lawful). First of all, the presence of an operational system does not impact the performance of the car. It does not increase the fuel consumption and does not worsen the performance.

However, drawbacks are the sediments accumulating both on the EGR system and the elements of the particulate matter filter. It is of more importance when the car is driven often for short distances, when the engine does not heat up well. This is one of the reasons why diesels are not recommended for drivers who drive purely in the cities and almost never on longer distances.


The future of the EURO 5 standard

The cars currently registered must meet the criteria of the EURO 6 standard. It is a matter of time – rather sooner than later – that EURO 7 is introduced, which would be another step forward to reducing the particulate matter and other substances emission. According to experts, it heralds a soon end of the combustion engines. The car manufacturers will be forced to replace them with the electric ones. What about the vehicles introduced to the market in 2001-2015, which meet the requirements of the EURO 5 standard?

Their users do not need to worry, for the time being. Such cars – with the diesel and gasoline engines – equipped with the particulate matter filters and catalysts, and other solutions limiting the harmful impact on the environment – still will not be the “victims of the regulations” for a longer time. The vehicles meeting the requirements of the EURO 5 standard will be allowed even in the clean transport zones until 2030.



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Although not everybody is fond of them, the EURO standards – limiting i.a. particulate matter emission. What has the EURO 5 standard introduced?
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