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Emission Standards

Emission Standards in Europe and USA
for Buses, Trucks and Off-road machinery

Regulated Emissions
The regulated emissions are carbon monoxide, hydrocarbon, nitrogen oxides and particulate matter. Limit values are given in grams per kilowatt-hour in Europe, and in grams per brake horse power-hour in USA. Regulations will be much more stringent during the next decade.

Standards for Europe
The European Union sets the emission standards (Euro 5, Euro 6 ...) for produced heavy duty diesel engines in Europe with regards to test cycles and emission levels for the regulated emissions. Local test procedures can be used on vehicles, especially buses, to verify emission reduction levels. The test cycles for manufacturers have been changed from steady state test cycle to transient test cycle, which are more representative of actual driving conditions.

EPA and CARB Sets Emission Standards for USA
The Environmental Protection Agency (EPA) sets the emission standards in USA, for all pollution sources. Due to its unique climate conditions, the state of California requires more stringent emissions standards. Therefore, it was allowed under the Federal Clean Air Act to draft its own emission standards.

In the year 2000 another 13 American states followed California and supported the standards from the Californian Air Resource Board (CARB) to be introduced in 2004. The PM levels in USA will remain high as compared to Europe until 2007, when the levels are required to be even lower than the European levels for 2008.  

Off-Road Machinery
Emission standards for off-road machinery with diesel engines have been in force in the United States since January 1996. Sweden followed an EU-directive and introduced such standards during 1998. The introduction of these standards was a two-step process. The step 1 limited values was enforced during 1998-2000, and the step 2 values - introduced during the 2001-04 timeframe. This standard applies to new machinery.

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Visiting address: Njurundavägen 16, 862 40 Njurunda, Sweden. STT Emtec, engine and emission technology.