Emission standards set limits on the amount of specific pollutants that vehicles can release into the environment. The pollutants usually regulated by emissions standards are: various compounds of nitrogen oxide (NOX);carbon monoxide (CO); hydrocarbons (HC); and particulate matter (PM).
Unfortunately, there are no universally accepted standards.
A set of European Union directives control standards throughout the EU; and some other vehicle-rich countries like India and Japan set their own standards. Other nations such as China are basing their standards on the European model. In most countries of the world, pollutant emissions are measured in grams per kilometer (g/km).
The EPA (Environmental Protection Agency) controls standards in the USA. In that country, the unusual hybrid measure of grams per mile (g/mi) is used.
USA
| Emissions Standard Program | |
Tier 1 |
The lowest standard |
NLEV (National Low Emission Vehicle Program) |
A voluntary program, where the average emissions level must meet LEV standard |
California (CARB) |
The California Clean Air Act sets standards for that state alone, generally more stringent than national standards |
Tier 2 |
National mandatory standards, phased in 2004-2009 |
Emissions Standard Level |
||
T1 |
Tier 1 |
The least stringent standards |
TLEV |
Transitional Low Emission Vehicle |
Tougher than T1 on hydrocarbons (HC) |
LEV |
Low Emission Vehicle |
Tougher than TLEV on HC and nitrogen oxides (NOX) |
ULEV |
Ultra Low Emission Vehicle |
Tougher than LEV on HC |
SULEV |
Super Ultra Low Emission Vehicle |
Tougher than ULEV on HC and NOX |
ZEV |
Zero Emission Vehicle |
Theoretically, no emissions |
Variations on these standards such as LEVII and SULEVII have also been created, as have other categories, such as ILEV (Inherently Low-Emission Vehicle); PZEV (Partial Zero Emission Vehicle); and AT-PZEV (Advanced Technology Partial Zero Emission Vehicle).
European Union
Petrol/Gasoline Standard |
Date |
CO |
HC |
HC+NOx |
NOx |
PM |
Euro I |
July 1992 |
2.72 (3.16) |
– |
0.97 (1.13) |
– |
– |
Euro II |
Jan. 1996 |
2.2 |
– |
0.5 |
– |
– |
Euro III |
Jan. 2000 |
2.30 |
0.20 |
– |
0.15 |
– |
Euro IV |
Jan. 2005 |
1.0 |
0.10 |
– |
0.08 |
– |
Euro V(proposed) |
Sept. 2009 |
1.0 |
0.10 |
– |
0.06 |
0.005b |
Euro VI (proposed) |
Sept. 2014 |
1.0 |
0.10 |
– |
0.06 |
0.005 |
