EN590 / EURO 4 / EURO 5 / ULSD

Reducing Toxic Emissions

In the European Union emissions of nitrogen oxides (NOx), total hydrocarbon (THC), non-methane hydrocarbons (NMHC), carbon monoxide (CO) and particulate matter (PM) are regulated for most vehicle types, including cars, trucks (lorries), locomotives, tractors and similar machinery, barges, but excluding seagoing ships and aeroplanes. For each vehicle type, different standards apply. Compliance is determined by running the engine at a standardised test cycle. Non-compliant vehicles cannot be sold in the EU, but new standards do not apply to vehicles already on the roads. No use of specific technologies is mandated to meet the standards, though available technology is considered when setting the standards. New models introduced must meet current or planned standards, but minor lifecycle model revisions may continue to be offered with pre-compliant engines.

Along with Emissions standards the European Union has also mandated a number of computer on-board diagnostics for the purposes of increasing safety for drivers. These standards are used in relation to the emissions standards.

In the early 2000s, Australia began harmonising Australian Design Rule certification for new motor vehicle emissions with Euro categories. Euro III was introduced on 1 January 2006 and is progressively being introduced to align with European introduction dates.


The stages are typically referred to as Euro 1, Euro 2, Euro 3, Euro 4, Euro 5 and Euro 6 for Light Duty Vehicle standards. The corresponding series of standards for Heavy Duty Vehicles use Roman, rather than Arabic numerals (Euro I, Euro II, etc.)

The legal framework consists in a series of directives, each amendments to the 1970 Directive 70/220/EEC. The following is a summary list of the standards, when they come into force, what they apply to, and which EU directives provide the definition of the standard.

  • Euro 1 (1992):
    • For passenger cars—91/441/EEC.
    • Also for passenger cars and light trucks—93/59/EEC.
  • Euro 2 (1996) for passenger cars—94/12/EC (& 96/69/EC)
    • For motorcycle—2002/51/EC (row A)—2006/120/EC
  • Euro 3 (2000) for any vehicle—98/69/EC
    • For motorcycle—2002/51/EC (row B)—2006/120/EC
  • Euro 4 (2005) for any vehicle—98/69/EC (& 2002/80/EC)
  • Euro 5 (2009/9) for light passenger and commercial vehicles—715/2007/EC
  • Euro 6 (2014) for light passenger and commercial vehicles—459/2012/EC

These limits supersede the original directive on emission limits 70/220/EEC.

The classifications for vehicle category are defined by:

  • Commission Directive 2001/116/EC of 20 December 2001, adapting to technical progress Council Directive 70/156/EEC on the approximation of the laws of the Member States relating to the type-approval of motor vehicles and their trailers
  • Directive 2002/24/EC of the European Parliament and of the Council of 18 March 2002 relating to the type-approval of two or three-wheeled motor vehicles and repealing Council Directive 92/61/EEC


Since the Euro 2 stage, EU regulations introduce different emission limits for diesel and petrol vehicles. Diesels have more stringent CO standards but are allowed higher NOx emissions. Petrol-powered vehicles are exempted from particulate matter (PM) standards through to the Euro 4 stage, but vehicles with direct injection engines are subject to a limit of 0.005 g/km for Euro 5 and Euro 6. A particulate number standard (P) or (PN) has been introduced in 2011 with Euro 5b for diesel engines and in 2014 with Euro 6 for petrol engines.

From a technical perspective, European emissions standards do not reflect everyday usage of the vehicle as manufacturers are allowed to lighten the vehicle by removing the back seats, improve aerodynamics by taping over grilles and door handles or reduce the load on the generator by switching off the headlights, the passenger compartment fan or simply disconnecting the alternator which charges the battery.


Although EN590 covers numerous fuel characteristics, water content is the most relevant contaminant for fuel maintenance. To comply with EN590, fuel can contain no more than 200mg of water per kg of fuel.

This is an extremely demanding standard. 200mg of water per kg of fuel represents just 0.02% water contamination. Because modern biodiesel blends absorb water naturally (i.e. they are hygroscopic) it is practically impossible to adhere to the standard without regular testing and the use of a water extraction process such as a polishing systemor regular tank cleaning.


EN590 was introduced to coincide with the development of new emissions standards across the European Union. The overall goal has been to reduce the sulfur content of diesel fuel. Sulfur had been used as a lubricant in the fuel. Its role is taken by special additives in ULSD.

Since 2007, diesel that conforms to EN590 has been referred to as Ultra Low Sulfur Diesel (ULSD) in the European Union. The phrase “Ultra Low Sulfur Diesel” is governed by different standards in other parts of the world.

With the number of vehicles roaming on the streets around the world, who is there to monitor the toxins being emitted out in the air? Good thing, the European Union (EU) made the Euro emission standards to limit the amount of harmful chemicals that spreads in the air.

If you're wondering what it means and why we need it, just think about the chemicals being emitted by millions of vehicles across the entire planet. These chemicals pollute the air that all humans and animals, including plants, breathe; more pollutants simply means health problems, and more health problems could possibly lead to increased mortality rate.

What does European emission standards mean? 

Basically, the Euro emission standards seek to limit the vehicle’s toxic gas in hopes to attain a cleaner, breathable air. The 1st Euro level (Euro 1) was introduced in 1992 as an initiative by the EU to regulate and standardize the amount of carbon monoxide (CO) and other poisonous chemicals being emitted by motor vehicles. 

Currently, there are 6 levels of Euro emission standards adopted in different parts of the world. The latest, Euro 6, was introduced in September 2014 – 22 years after the 1st emission level came out. 

The highest Euro level only permits CO emission of 1.0g/km for gasoline and 0.5g/km for diesel. It is focused more on lowering the Nitrogen Oxide (NOx), which is also harmful to humans, as well as to animals. 

Current Euro level in the Philippines

The Philippines is now following Euro 4 emission standard. To put things in perspective, North America and Europe have implemented Euro 3 in 2005. Clearly, we are behind when it comes to emission standard, which could be attributed to the country’s lack of resources.

Of note, the Philippines’ Department of Environment and Natural Resources (DENR) pushed for the implementation of the Euro 4 compliance in July 2015. However, a number of local oil companies and automotive manufactures stressed out that they prefer to follow the original timeline set by the Department of Energy (DOE), which is January 2016.

Related: EVAP ready to help PH government’s Jeepney Modernization Program

The upgrade from Euro 2 to Euro 4 reduces the toxic sulfur that comes out of the combustion engine by 450 parts per million (ppm), both on diesel and gasoline. Benzene, which is also considered harmful to humans, was also cut off by 4%. Standard CO emission permitted by Euro 4 on gasoline is 1.0g/km, while it's 0.5g/km for the diesel. 

The local implementation of Euro 4 limit falls under the "Philippine Clean Air Act of 1999," which requires vehicles with Euro 4 fuel to comply with the standards issued by the DENR.

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