27 March 2003

Japan’s Ministry of the Environment adopted new, stringent diesel emission standards for new diesel engines and vehicles manufactured from the Fall of 2005, as proposed in April 2002.

The 2005 regulations bring significant reductions of emissions of diesel particulate matter (PM) and nitrogen oxides (NOx) for both light- and heavy-duty engines:

  • For trucks and buses over 3.5 tons, the new PM standard is 0.027 g/kWh, down from the current 0.18 g/kWh (or 85% reduction). The new NOx standard is 2 g/kWh, down from the current 3.38 g/kWh (41% reduction).
  • For passenger cars and small to medium-sized trucks and buses, the new PM standards are 0.013-0.015 g/km (depending on vehicle category), down from the current 0.052-0.06 g/km (75% reduction). The NOx standards are 0.14-0.25 g/km, compared to the current 0.28-0.49 g/km (50% reduction).

Japanese, EU and US emission standards are all expressed using different test cycles, so exact comparisons are not always possible. Numerically, the JP 2005 standards for heavy-duty engines are very similar to the Euro 5 standard (2 g/kWh NOx, 0.02/0.03 g/kWh PM over a steady-state/transient test). However, the Euro 5 standard comes to power only in 2008. Therefore, beginning in the fall 2005 and until the US 2007 standards become effective, Japan will have the most stringent emissions standards in the world.

Also the new light-duty standards are more stringent than the Euro 4/2005 regulation (no Euro 5 regulation has been yet adopted or proposed for light-duty vehicles).

Source: Kyodo