European Union Emissions Standards

The development of the standards 

The European Economic Community (EEC), now the European Union (EU), issued its first directive (Directive 70/220/EEC) detailing the measures to be taken against air pollution by gases from passenger cars and light commercial vehicles in 1970. All member states of the EEC adopted this directive from 1971, either as a replacement or in addition to any existing national regulation of vehicle emissions. Although amended considerably since its introduction, Directive 70/220/EEC remains the basis for the current EU passenger car and light commercial vehicle emissions laws, known as Euro 3, which are detailed in directive 98/69/EC.

Regulation of the emissions from heavy-duty diesel vehicles and buses was introduced in 1988 (Directive 88/77/EEC). This legislation also has been amended a number of times, and the current set of laws, also known as Euro 3, are detailed in Directive 1999/96/EC.

The legislation for passenger cars, light commercial vehicles and heavy-duty diesel vehicles has been aligned since 1992 into a series of standards known as Euro 1, 2, 3, 4 and 5. Although the dates for compliance with each standard as detailed in the separate directives differs for each vehicle class, they may be considered as following the timeline shown above.
Dates for compliance

Directive 70/220/EEC introduced the concept of “type approval,” which defines the process by which a particular engine/vehicle design is tested and approved as meeting the requirements of the directive.

With type approval came two dates for compliance with the legislation. By the first date, all new engine designs must meet the new emissions standard. By the second date, typically one year after the type approval date, it becomes mandatory for all new vehicles sold to meet the emissions standard. The process of type approval is still used today, although compliance dates may differ for different vehicle types.

The directives also include provisions for each member state to introduce tax incentives to encourage the early adoption of vehicles meeting the new emissions standard. The tax incentives come into force from the type approval date of the preceding standard. This can result in vehicles meeting the next emissions standard entering the market at least two years before compliance becomes mandatory.

The table below outlines these key dates for the current Euro 3 legislation, the forthcoming Euro 4 legislation and, its successor Euro 5.

Limits for compliance

Within each of the regulations, the specific pollutants to be evaluated, the method of evaluation and the limits to meet vary for different classes of vehicles. Figures T1, T2 and T3 illustrate successive reductions in levels of each pollutant for passenger cars and heavy-duty diesel vehicles in moving from Euro 1 to Euro 4.

Gasoline passenger car

For gasoline-fuelled passenger cars, limits are set for the emission of CO, hydrocarbons (HC) and NOx. Directive 70/220/EEC originally set limits for only carbon monoxide and hydrocarbons, the regulation of NOx use subsequently introduced in a 1977 amendment. Since then, the limits for all three pollutants have been successively reduced. The limits currently set are constructed from a series of six test cycles that evaluate emissions under conditions including cold starting and idling. Figure T1 shows the changes in limits from Euro 1 to Euro 4

Diesel passenger car

Diesel-fuelled passenger cars originally were covered by the same standards as gasoline cars until the regulation of particulate emissions was introduced in 1988. Since then, although regulated by the same directives as gasoline, diesel passenger cars have been evaluated against a different range of test cycles (only two out of the six used for gasoline) and have separate limits to meet for compliance. The change in limits for diesel passenger cars from Euro 1 to Euro 4 is shown in Figure T2.

Figure 1

Figure 2

Heavy-duty diesel trucks

The regulation of heavy-duty diesel truck emissions is maintained through a separate set of directives than those for passenger cars and light commercial vehicles. Although the pollutants evaluated are the same, the test procedures used are different.

The 13 mode steady state cycle test (ECE-R49) used for the Euro 1 and Euro 2 standards was replaced by two tests in Euro 3, a stationary cycle test (ESC) and a transient cycle test (ETC), which evaluates non-methane hydrocarbons (NMHC) rather than all HC. The ETC test also evaluates methane emissions; however, this is only regulated for gas engine vehicles and is not included in the tables below. Either of these tests could be used for type approval to Euro 3; however, both are required for approval to Euro 4. In addition to the regulation of CO, HC, NOx and particulates, the regulation of smoke and NMHC was introduced with Euro 3 and is evaluated using the load response cycle test (ELR). The change in the permitted levels of these pollutants from Euro 1 to Euro 5 is shown in figure T3. At present, Euro 5 limits have only been proposed for heavy-duty diesel vehicles.

The limits shown in figures T3 and T4 are for evaluation against the test cycles ECE R-49 (Euro 1 & 2) and ESC/ELR cycles for Euro 3, 4 and 5.

Figure T3

Notes
1 - For engines <85kW
2 - For engines >85kW
3 - For engines of swept volume <0.75dm3 and rated power speed >3000 min-1 only

Figure T4

Notes
1 - For enhanced environmentally friendly vehicles (EEVs) only
2 - For engines of swept volume <0.75dm3 and rated power speed >3000 min-1 only