Thailand: Heavy-duty: Emissions


Thailand’s heavy-duty emissions standards track those of Europe, with the Euro III standard currently in effect.

Standard type
Conventional pollutant emission limits

Current Standard
Euro III (in Thai)

Motor vehicles over 3,500 kg, equipped with compression ignition engines or positive ignition natural gas (NG) or (liquified petroleum gas) LPG engines.


Thailand has subscribed to the European system of heavy-duty vehicle emissions standards since May 1998.

Emission standards for on-road vehicles in Thailand are formulated by the Pollution Control Department (PCD) and adopted by the Ministry of Industry (MOI) and/or the Ministry of Science, Technology, and Environment (MOSTE).

The Pollution Control Department was established on June 4, 1992, under the Royal Decree on the Organizational Division of Pollution Control Department, Ministry of Science, Technology and Environment B.E. 2535(1992), as result of the Enhancement and Conversation of the National Environment Quality Act B.E. 2535 (1992).

Technical Standards

New Vehicle Regulations

New heavy-duty diesel vehicle regulations are based on European standards and emission test procedures.

Standards for exhaust emissions of new heavy-duty diesel engines (in g/kWh)
Standard Level Reference standard Test Cycle CO HC NOx PM NMHC CH4(1) Smoke Enforcement Date
Level 1
Pre-Euro R-49 11.2 2.4 14.4
Level 2
Euro I 4.5 1.1 8.0 0.36 12 May 1998
Level 3
Euro II 4.0 1.1 7.0 0.15 23 May 1999
Level 4
Euro III ESC, ELR 2.1 0.66 5.0 0.10/0.13(2) 0.8 1 Jan 2007
Euro III EEV 1.5 0.25 2.0 0.02 0.15
Euro III ETC 5.45 5.0 0.16/0.21(2) 0.78 0.16
Euro III EEV 3.0 2.0 0.02 0.40 0.65

(1) For engines that use natural gas as fuel

(2) for engines of less than 0.75 dm3 swept volume per cylinder and a rated power speed of more than 3000 min-1

EEV – Enhanced Environmentally-Friendly Vehicles

In-Use Vehicle Regulations

In-use diesel vehicles in Thailand must meet the following black smoke standards.1

Diesel Vehicle Black Smoke Standards
Standard Measuring System Measuring Method
50% Filter Free Acceleration
45% Opacity
40% Filter Full Load
35% Opacity

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