Euro 1 to Euro 7, a complete guide on emission Standards

Euro standards were created in 1992 to limit the amount of exhaust emissions produced by petrol and diesel vehicles to reduce the impact of emissions on the planet. Euro emission standards are regulations introduced to control the level of harmful emissions from vehicles, mainly Nitrogen oxides (NOx), Carbon monoxide (CO), and hydrocarbons (HC).

Euro 7 will be introduced on 1st July 2025 and will be the strictest standard so far. All new cars sold from 2025 will need to emit less than 60 milligrams of NOx to meet the standard. It is expected that Euro 7 will be in place between five and 10 years, this new standard shouldn’t affect the UK’s low emission zones but with the expanding London ULEZ it is always useful to know which cars are compliant. 

• Please note that these standards are periodically updated with tougher limits brought in with each iteration. The aim of these standards is to reduce the levels of harmful exhaust emissions, chiefly: Nitrogen oxides (NOx), Carbon monoxide (CO), Hydrocarbons (HC), Particulate matter (PM). These standards are having a positive effect on improving air quality.

   

  Emission Standard	Year Introduced	Key Changes
  Euro 1	1992	First set of emission standards introduced. Required the switch to unleaded petrol and the universal fitting of a catalytic converter. Aimed to limit emissions of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) from gasoline and diesel vehicles.
  Euro 2	1996	Further reduced the limit for carbon monoxide emissions and also reduced the combined limit for unburned hydrocarbons and oxides of nitrogen for both petrol and diesel vehicles. Introduced different emissions limits for petrol and diesel.
  Euro 3	200	Modified the test procedure to eliminate the engine warm-up period and further reduced permitted carbon monoxide and diesel particulate limits. Added a separate NOx limit for diesel engines and introduced separate HC and NOx limits for petrol engines.
  Euro 4	2005	Further reduced permitted limits for CO, HC, NOx, and PM. Some diesel cars were fitted with particulate filters.
  Euro 5	2009	Further reduced permitted limits for CO, HC, NOx, and PM.
  Euro 6	2014	Sets a legally binding CO2 emissions target that most car manufacturers must adhere to. The main focus of Euro 6 is reducing nitrogen oxide (NOx) and particulate matter (PM) emissions
  Euro 7	-2025	Sets limits for non-exhaust emissions such as particles from brakes and tyres. It additionally covers minimum performance requirements for battery durability in electric cars, and imposes stricter vehicle lifetime requirements. The regulation also provides for the use of advanced technologies and emission-monitoring tools[. Takes the lowest limits from Euro 6, and apply them to all new cars, regardless of what fuel they run on. For example, the limit for NOx under Euro 6 is 60 milligrams per kilometre for petrol cars, and 80 milligrams per kilometre for diesels

• A brief history of Emission standards

  Euro 1 implemented in 1992 was the first set of emission standards introduced. It required the switch to unleaded petrol and the universal fitting of a catalytic converter. It aimed to limit emissions of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) from gasoline and diesel vehicles. 

  Euro 2 was implemented in 1996 and further tightened the limits on CO, HC, and NOx emissions for new vehicles, promoting the use of more advanced emission control technologies. It also introduced different emission limits for petrol and diesel vehicles.

  Euro 3 introduced in 2000 changed the test procedure to eliminate the engine warmup period and introduced stricter limits on CO, HC, and NOx emissions, as well as the introduction of separate HC and NOx limits for petrol engines. 

  Euro 4 came into effect in 2005 and focused on cleaning up emissions from diesel cars, especially particle matter and NOx, some diesel cars were fitted with particle filters. It also significantly reduced the allowable levels of CO, HC, NOx, and PM emissions from vehicles. 

  Euro 5 introduced in 2009 further tightened the limits on particulate emissions from diesel Engines and all diesel motors wanted particulate filters to fulfill the brand new requirements. Further tightening of NOx limits were put into place and a particulates limit was introduced for direct-injection petrol engines. Euro 5 also introduced a limit on particle numbers for diesel engines in addition to the particle weight limit to counter very fine particle emissions. 

  Euro 6 implemented in 2014 further reduced NOx emissions from diesel engines at 67% compared to Euro 5. It also introduced Exhaust Gas Recirculation which replaces some of the intake of air with recycled exhaust gas to reduce the amount of nitrogen that can be oxidised and turned into NOx during combustion.