Photo: © Zdenek Sasek /

Post-Euro 6 car emissions standards

A new ICCT report highlights the limitations of current EU car emissions standards and provides detailed recommendations for how to overcome them.

In October, the International Council for Clean Transportation (ICCT) published a report that points out problems and limitations of the EU’s existing Euro 6 emission standards for light-duty vehicles, compares them to current and future regulations in other parts of the world, and offers policy recommendations for new, post-Euro 6 standards.

The recommendations are timely, since the European Commission has fairly recently started the regulatory work aimed at the next stage of emission standards. Clearly, the objective of any new EU standards are to markedly improve the emissions performance of new road vehicles in order to minimise, and ultimately eliminate, their contribution to the persistent air quality problems across Europe.

Motor vehicle emissions of various air pollutants, including carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and tiny particles (PM) contribute directly as well as indirectly to health and environmental damage. The indirect effects result primarily from their role as precursors for the formation of PM2.5 and ground-level ozone.

Regulatory action at the EU level started in 1970 with a directive that established emission limits for CO and HC from petrol vehicles. Emission limits for NOx were introduced in 1977, and extensions to also cover the gaseous pollutants of diesel vehicles were passed in 1983. A particulate mass (PM) emissions limit was introduced for diesel vehicles in 1988.

What are known today as the Euro 1 standards were adopted in 1991. Since then, the EU has progressively tightened emission limits through the Euro 2 (1996), Euro 3 and 4 (1998), and Euro 5 and 6 (2007) standards.

It is no news that the Euro standards have been ineffective in reducing the real-world NOx emissions from diesel vehicles. The ICCT points out that from 2000 to 2016, that is from Euro 3 to Euro 6, the nominal NOx limits set by the diesel Euro standards have been reduced by 84 per cent, but over the same time period NOx emissions from transport have only fallen by 32 per cent.

NOx emissions from petrol vehicles, on the other hand, have decreased proportionally with reductions in the limit set by the applicable Euro standard.
As the European Commission is now turning its attention to the development of post-Euro 6 emission standards, the ICCT has presented a series of recommendations covering several topics, with the aim of strengthening the current vehicle emission standards for light-duty vehicles.
These topics include:

  • Emissions of regulated, unregulated, and climate-forcing pollutants;
  • Testing regimes, data evaluation methods, and boundary conditions for demonstrating compliance with type-approval and in-service conformity testing;
  • Measures to improve durability, emissions performance, and compliance with standards throughout the useful life of the vehicles.

The list of recommendations is split into different categories and presents many detailed proposals. A few highlights are given below.

In addition to fuel- and technology-neutral emissions limits and standards upgraded to bring them in line with other markets, ICCT is calling for additional limits for methane and nitrous oxide (as greenhouse gases), ammonia, all volatile organic compounds (not solely hydrocarbons), and specific limits for nitrogen dioxide in addition to total nitrogen oxides. It also wants to improve and strengthen emission controls for ultrafine particles and the establishment of emission limits for brake wear particles.

ICCT wants better testing conditions, including a new low-temperature test with tighter emission limits covering more pollutants. It also wants to see improvements to the Real Driving Emissions (RDE) test. Moreover, requirements for durability, on-board diagnostics and monitoring, as well as market surveillance mechanisms, should be strengthened.

Christer Ågren

The full report is at:



In this issue