Japan: Heavy-duty: Emissions


Japan’s “Post New Long-Term Emissions Standards” have applied to all new heavy-duty vehicles since 2010 (and type approvals in 2009). These standards—which tightened the NOX emission limit for diesel vehicles in 2016—are equivalent in stringency to Euro VI and U.S. 2010 standards. As of 2016, these standards apply the World Harmonized Transient Cycle (WHTC) for certification testing.

Standard type
Conventional pollutant emission limits

Regulating Body
Ministry of the Environment, MOE

New type-approved trucks and buses with GVW > 3.5 t


Limit values for new truck and bus engines in Japan are set by the Ministry of the Environment under authority of Japan’s Air Pollution Control Law. Within a span of six years, exhaust emission standards were strengthened three times, from 2003-2005 (the “New Short Term Standards”), in 2005 (the “New Long Term Standards”), and in 2009 (the “Post New Long Term Standards”). Testing for these standards has been conducted over Japan-specific drive cycles.

Technical Standards

Two types of exhaust emission standards are established in Japan, denoted as “mean” and “max.” The “mean” standards are to be met as a type approval limit and as a production average. The “max” standards are to be met generally as an individual limit in series production and as type approval limit if sales are less than 2000 per vehicle model per year. The “max” standards are shown in parentheses in the following tables.

Implementation dates in the tables refer to new vehicle models. Current production models are often allowed a delay of up to one year.

Diesel Vehicles

Emission standards for new diesel-fueled commercial vehicles are summarized below for heavy-duty vehicles (engine dynamometer test).

Diesel Emission Standards for Heavy-duty Commercial Vehicles
GVW > 3500 kg (> 2500 kg before 2005)
Date Test Unit CO HC NOx PM
mean (max) mean (max) mean (max) mean (max)
1988/89 6 mode ppm 790 (980) 510 (670) DI: 400 (520)
IDI: 260 (350)
1994 13 mode g/kWh 7.40 (9.20) 2.90 (3.80) DI: 6.00 (7.80)
IDI: 5.00 (6.80)
0.70 (0.96)
1997a 7.40 (9.20) 2.90 (3.80) 4.50 (5.80) 0.25 (0.49)
2003b 2.22 0.87 3.38 0.18
2005c JE05 2.22 0.17d 2.0 0.027
2009 2.22 0.17d 0.7 0.01
2016 WHTC 2.22 0.17d 0.4e 0.01
a – 1997: GVW ≤ 3500 kg; 1998: 3500 < GVW ≤ 12000 kg; 1999: GVW > 12000 kg
b – 2003: GVW ≤ 12000 kg; 2004: GVW > 12000 kg
c – full implementation by the end of 2005
d – non-methane hydrocarbons
e – enforcement: 2016 for GVW>7.5t; 2017 for tractors; 2018 for 3.5t < GVW ≤ 7.5t

Gasoline Vehicles

Emission standards for new gasoline-fueled commercial vehicles are summarized below for heavy-duty vehicles.

Gasoline Emission Standards for Heavy-duty Commercial Vehicles
Date Test mode Maximum allowable emissions (g/km)
2005 JE05 16.0 0.23 0.7
2009 16.0 0.23 0.7 0.01
*PM values apply only to direct-injection, lean-burn vehicles equipped with absorption-type NOx reduction catalysts


Prior to 2005, heavy-duty engines were tested over the 13-mode cycle and the 6-mode cycle. The test procedure for heavy-duty engines for the 2005 and 2009 standards is the JE05 mode cycle (hot start version). Vehicles and engines were tested using 50 ppm S fuel for the 2005 standards, and 10 ppm S for the 2009 standards. In July 2010, the Ministry of Environment changed the planned test cycle for the 2016 standards from the JE05 model to the World Harmonized Transient Cycle (WHTC) with the aim of reducing technology costs through increased harmonization.

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