European emission standards for vehicles

The first EU-wide standard–known as Euro 1–was launched in 1992, while emission regulations date back to 1970.

Catalytic converters became mandatory on new vehicles sold in the UK as Europe became aware of the need to decrease emissions from tailpipe. This injection of fuel on new vehicles was efficiently standardized.

Since then, we have gone through a sequence of Euro emission standards, leading to the present Euro 6, introduced for new approvals in September 2014

The regulations–intended to become more stringent over time–set acceptable boundaries for exhaust emissions of new cars and heavy-duty trucks sold in member countries of the EU and EEA (European Economic Area).

According to the EU, "Road transport air pollutant emissions are a major contribution to the general state of air quality in Europe," with other main sources being industry and power generation.

Euro emission standards are aimed at reducing damaging exhaust emission concentrations, mainly:

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

SMMT (the society of motor manufacturers and traders) says these standards have had a positive effect and claims that 50 new cars would be needed today to produce the same amount of pollutants that a vehicle built in the 1970's produces.

The SMMT has quoted the following figures in support:

• Carbon monoxide (CO): petrol down 63%, diesel down 82% since 1993
• Hydrocarbons (HC): petrol down 50% since 2001
• Nitrogen oxide (NOx): down 84% since 2001
• Particulate matter (PM): diesel down 96% since 1993

Due to the distinct kinds of emissions produced by petrol and diesel engines, they are subject to varying standards.

In diesel, for instance, more particulate matter –or soot–is produced which led to the implementation of diesel particulate filters (DPFs).

However, the EU has indicated that the emissions of NOx from road transport "Have not reduced as much as expected. Since the emissions in actual driving circumstances (especially for diesel vehicles) are often greater than those measured during an approval test.

As pointed out by the UK government in December 2016, 34% of UK NOx emissions were accounted by road transport during 2015. Due to the increased contribution from diesel vehicles the atmospheric NOx reduction rate has slowed down.

Meanwhile, the average carbon emissions of new cars have fallen by more than half and will achieve the target average of 95g / km by 2020. CO2 emissions are related to the effects of climate change and subject to various regulations.

The following table shows the different Euro categories for new vehicle models approved after a specific date. The table is reproduced from that developed by the European Commission. Each car sold up to one year after the following dates should meet the required standards, but check directly with your manufacturer if you are uncertain.

If your car is older than all the dates listed below, it will not even be classified as Euro 1, so certain cities may charge or prohibit you from driving it at certain times.

European Emission Standards and their introduction

Important Note: single sales of trucks and car already constructed and shipped by the manufacturer before 1 June 2015 would continue to be sold until 1 September 2016 as explained in the Jaguar website. This implies that a vehicle sold before 1 September 2016 could still be fitted with a Euro 5 engine. To be sure, check with the manufacturer.

Euro 1

Implementation date (new approvals): 1 July 1992

Implementation date (all new registrations): 31 December 1992

In July 1992, the first euro emission standards were introduced throughout Europe and the regulations were nowhere near as strict. That said, all new vehicles had been obliged to fit catalytic converters and Euro 1 had to move to unleaded petrol. In the case of diesel engines, only hydrocarbons and oxides with nitrogen were screened alongside particulate matter at that time. The regulations have been tightening up over the years and the limits have reduced.

Euro 1 emissions standards (petrol) CO: 2.72g/km HC + NOx: 0.97g/km

Euro 1 emissions standards (diesel) CO: 2.72g/km HC + NOx: 0.97g/km PM: 0.14g/km

Euro 2

Implementation date (new approvals): 1 January 1996

Implementation date (all new registrations): 1 January 1997

Euro 2 decreased carbon monoxide levels and the combined levels for unburned hydrocarbons and nitrogen oxide and introduced a range of petroleum and diesel engine levels.

Euro 2 emissions standards (petrol) CO: 2.2g/km HC + NOx: 0.5g/km

Euro 2 emissions standards (diesel) CO: 1.0g/km HC + NOx: 0.7g/km PM: 0.08g/km

Euro 3

Implementation date (new approvals): 1 January 2000

Implementation date (all new registrations): 1 January 2001

Euro 3 splits the petrol and diesel engine hydrocarbons and nitrogen oxide limits and adds a separate nitrogen oxide threshold in diesel vehicles. The warm-up period has been deleted from the test.

Euro 3 emissions standards (petrol) CO: 2.3g/km THC: 0.20g/km NOx: 0.15g/km

Euro 3 emissions standards (diesel) CO: 0.66g/km HC + NOx: 0.56g/km NOx: 0.50g/km PM: 0.05g/km

Euro 4

Implementation date (new approvals): 1 January 2005

Implementation date (all new registrations): 1 January 2006

Euro 4 emissions standards (petrol) CO: 1.0g/km THC: 0.10g/km NOx: 0.08g/km

Euro 4 emissions standards (diesel) CO: 0.50g/km HC + NOx: 0.30g/km NOx: 0.25g/km PM: 0.025g/km

Euro 5

Implementation (new approvals): 1 September 2009

Date of implementation (all new registrations): 1 January 2011

Euro 5's big news was to introduce Particle Filters (DPFs) for diesel engines and lowering limits across the board. Diesel vehicles were subject to a fresh particulate-number threshold for type approvals from September 2011 and fresh vehicles from January 2013. Every new diesel vehicle is equipped with the DPF that captures 99 percent of all particulate matter. Cars complying with Euro 5 norms emit an equivalent of one grain of sand per kilometer driven.

Euro 5 truck emissions standards (petrol) CO: 1.0g/km THC: 0.10g/km NMHC: 0.068g/km NOx: 0.06g/km PM: 0.005g/km (direct injection only)

Euro 5 emissions standards (diesel) CO: 0.50g/km HC + NOx: 0.23g/km NOx: 0.18g/km PM: 0.005g/km PN [#/km]: 6.0x10 ^11/km

Euro 6

In September 2015 most new registrations implemented the sixth and current iteration of the Euro Emissions Standard. The allowable amount of NOx was cut from 0.18g / km in Euro 5 to 0.08g / km for diesels.

A focus on diesel NOx was the immediate outcome of a research related to these emissions with respiratory issues.

Pollution control methods used by the biggest truck manufacturers (Euro 6)

Manufacturers attempt to comply with the Euro Standards

Euro V standards for heavy-duty diesel engines were in effect in Europe from around the end of 2008, which reduced NOx emissions from  to 2.0 g / kWh from Euro IV's 3.5 g / kWh. Euro VI emission limitations were implemented in 2013 with 0,4 g / kWh of NOx and0.01 g / kWh of PM. The PN limit of 8.0x1011 particle/kWh was also implemented. At the Euro V level, OBD specifications were implemented and later increased in stringency for Euro VI. Off-cycle emission tests were implemented at Euro VI level.

To meet these new targets, some heavy-duty truck manufacturers, such as Iveco, MAN and DAF introduced Selective Catalytic Reduction (SCR), which injects a liquid-diminishing agent into the exhaust of a diesel vehicle using a catalyst. A chemical reaction transforms the oxide of nitrogen into harmless water and nitrogen expelled by the exhaust pipes.

The Exhaust Gas Recirculation (EGR) was an alternative technique used by Scania / MAN to meet Euro 6 requirements. Some of the exhaust gas is blended with intake air to reduce the burning temperature . In accordance with engine load or speed, the ECU of the vehicle helps to regulate the EGR.

Preparing emission standard for the future. Is Euro 7 on the horizon?

Currently, Euro 7 in Europe is little more than "chatter." There's a lot of lobbying and no formal proposal. Behind the VW’s ‘dieselgate’ scandal is a realization that the only way to prevent 'cheating' is real-world testing and tracking.

This ignores the fact that 'Dieselgate' was a VW car problem, with different Euro standards and tests, different and higher standards for PCV and HGV.

What is known as Euro 7 is being lobbied by towns and green movements who want cleaner air. Cummins thinks even cleaner systems can be built. It is therefore already working towards this objective.

Further calls for the EU to "very aggressively" improve the fuel economy at the Euro 7 were made by big fleet truck operators and clients.