The EU has adopted strict new caps on pollutant emissions from diesel and petrol cars, limiting in particular nitrogen oxides (NOx) and particulate matter (PM) which pose the most serious health and environmental problems.


Road transport contributes to air quality problems through vehicle emissions. Poor air quality leads to health problems such as respiratory and cardiovascular disease.

To preserve air quality, cars must meet certain standards for exhaust emissions before they can be approved for sale in the European Union. Successive 'Euro' emission standards for passenger cars and light vehicles were initiated in the EU as of 1993.

They have already helped achieve considerable reduction in air pollution from cars, for example by forcing carmakers to fit catalyst filters to exhaust pipes. Heavy-duty trucks and buses, off-road diesel vehicles and motorcycles are subject to separate emissions regulations, as are emissions of carbon dioxide (see EurActiv LinksDossier on Cars and CO2).

Reducing vehicle emissions is part of a larger strategy to tackle the negative health and environmental effects of air pollution created by all sectors. This so-called thematic strategy on air pollution was adopted by the Commission in September 2005, along with a Directive on ambient air quality, as part of the 6th environmental action programme and its related Clean Air for Europe (CAFE) programme launched in 2001(LinksDossier on the 6th EAP).


From Euro 4 to Euro 5 standards

The Euro 5 standards for cars will further restrict emissions, from both petrol and diesel cars, of carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and particulate matters (PM), which are considered harmful to human health. The tighter standards will apply as of September 2009 for new models of cars and in January 2011 for all new cars.

The new Directive will also close the current loop-holes, under the Euro 4 Directive, for heavy sports utility vehicles (SUVs) and four-wheel drives above 2,500 kg. 

The original aim of the Commission’s Euro 5 proposal was that the new rules come into force by mid-2008 for new car models and in 2010 for all new cars, but Parliament and member states agreed to delay its introduction by one year (EurActiv 18/09/06) in order to provide sufficient preparation time for building and testing adapted engines.

  • Optimising diesel engines

Emissions of the highly noxious pollutants known as nitrogen oxides (NOx) and particulate matter (PM) from diesel vehicles are currently four to five times higher than for petrol vehicles. The Euro 5 Directive aims to make diesel cars "catch up" - although not completely. 

The Euro 5 limits will reduce emissions of particulates from diesel cars by 80% compared to Euro 4. They will however be more lenient as regards NOx emissions, which will only have to be cut from 250mg/km to 180mg/km – against the current 70mg/km for petrol vehicles.

This leniency for diesel vehicles contrasts with legislation in the United States, which is "fuel-neutral". However, it is worth mentioning that diesel cars represent roughly half of all cars in the EU, whereas they represent less than 5% of those in the US.

To prepare for the new standards, carmakers are working on technologies to optimise diesel engines. The quantity and composition of emissions vary depending on several technical factors, including the quality of diesel fuel used; the type of engine and the engine tuning; the workload demand on the engine, etc. 

The tightening of vehicle standards is closely linked to fuel quality improvements. In some cases, fuel modifications are necessary to allow the introduction of new technologies that are needed in order to meet the tighter emissions standards. For example, the adoption of Euro 1 standards for gasoline vehicles required the develoment of unleaded gasoline. 

  • Making particulate filters compulsory

The emissions standards are always technology-neutral, which means that carmakers can use the technology of their choice to reduce emissions. At the time of their adoption, the Euro 4 standards were believed to require expensive particulate filters to be fitted onto diesel cars. But progress in the engine technology made it possible to meet the Euro 4 PM limit (25 mg/km) on most cars using advanced in-cylinder techniques and the diesel oxidation catalyst (DOC), without the need for a PM filter. Current Euro 5 proposals, however, given current technology, can only be achieved by fitting expensive filters to exhaust tubes.

  • Temporary exemptions for social needs vehicles… and SUVs  

Vehicles designed for specific social needs, such as ambulances and vans designed to transport disabled persons or to fulfil public services, will be allowed a transition period of three years to comply with the standards. 

So will "light commercial vehicles" weighing less than 3,500 kg, which include vans intended for the transport of materials, small pick-up trucks and sports utility vehicles (SUVs) – the bête noire of green groups, because of their high levels of fuel consumption and pollutant emissions. 

  • Tax incentives to reduce emissions

Member states are free to introduce fiscal incentives to reduce emissions beyond the Euro 4 emission standards which have applied since January 2005. Germany, for instance, has a tax exemption of about €600 for new cars bought if particle emissions are under 0.0085g/km. Similar incentives are proposed in France, Austria and the Netherlands. In January 2005, the Commission issued a guidance document for the purposes of countries wishing to go beyond Euro 4. 

  • International cooperation

Japan and the US have adopted similar legislation to the Euro emissions standards. Emerging countries in Asia, Africa and South America are also gradually adopting legislation on emissions standards and fuel requirements in order to avoid serious air pollution problems linked to the growing numbers of automobiles on their roads. In 2005, Indonesia, Nepal, Philipines, and Bangladesh remained under Euro 1 standards while most cities in India and China were applying Euro 3 standards. 

From Euro 5 to Euro 6 standards

Beyond Euro 5, the three institutions have agreed on introducing longer-term limits, under a Euro 6 stage that has been adopted at the same time as Euro 5, but will enter into force five years later. Euro 6 will set significantly lower emission limits for NOx emissions from diesel cars.

Overview of past and future measures in place since 1996:



Particulate matters (PM)/



Oxides of nitrogen (NOx) 


  Hydrocarbons (HC) (mg/km)  
- Diesel  Petrol Diesel Petrol Diesel Petrol
Euro 2 (1996) 80-100 - - - - -
Euro 3 (2000) 50 - 500 150 - 200
Euro 4 (2005) 25 - 250 80 - 100
Euro 5 (2009) 5 5 180 70 - 100

Euro 6(2014)

5 5 80 70 - 100


Commission Vice-President Günter Verheugen, responsible for enterprise and industry policy, stressed: “The Euro 5 and 6 regulation is important for improving the environmental performance of vehicles. It will not hamper the competitiveness of the EU’s car industry.”

Ivan Hodac, secretary-general of the European Automobile Manufacturers Association (ACEA) said that the new Euro 5 and 6 standards were "extremeley challenging", adding: "What concerns us, is that the proposed limit values will not only be extremely difficult to meet, but will have a significant counter-productive effect on reducing CO2 emissions from passenger cars." The group claims that costs related to the new standards have been underestimated by around 33% and that the price of diesel cars will rise by €900, causing a shift to gasoline cars and an increase in CO2 emissions of 6%. 

The European Federation for Transport and the Environment (T&E) strongly supports stronger emissions standards but regrets the weakness of the Euro 5 and 6 standards, notably as regards NOx emissions, which it says cause smog, respiratory problems and acid rain. The NGO also deplores the fact that four-wheel drive vehicles (or SUVs) have been allowed an additional three year transition period before having to comply with the new rules. "The Parliament, in its 'wisdom', has concluded that SUVs - these unsafe, antisocial, heavily-polluting cars - should be allowed to pump lethal emissions into the air for an extended period," said T&E Director Jos Dings. He added that the new legislation created an "unbelievable situation" where Euro 6 standards, to be enforced after 2014, will be weaker than those in California and ten other American states (40mg/km for both petrol and diesel cars): "An American consumer can buy a super-clean Mercedes diesel today in their local dealer, while a German will have to wait until 2015 to buy something even remotely similar. There is simply no excuse for allowing Europe to lose its leadership in this area." 


  • 13 December 2006: Parliament adopted a compromise report on the proposal.
  • 30 May 2007: Council confirms adoption of the compromise text.
  • September 2009: Euro 5 applies to all new car models (light commercial vehicles and special needs cars in September 2010).
  • January 2011: Euro 5 applies to all new cars (light commercial vehicles and special needs cars in January 2012).
  • September 2014: Euro 6 applies to all new car models (light commercial vehicles and special needs cars in January 2015).
  • September 2015: Euro 6 applies to all new cars (light commercial vehicles and special needs cars in January 2016).