Other NOx regulations

China: Domestic waterways

As part of their continued effort to curb air pollution in the country, the Ministry of Transport of the People’s Republic of China issued a regulation effective as of 1st September 2018, with validity of 5 years, that requires both international and national carriers operating within Chinese domestic waterways to comply, as a minimum, with IMO Tier II NOx requirements. This is mainly in effort to prevent old ‘dirty’ ships to be bought and brought into operation in China.


EU: Stage V inland waterway standards

The European Union emission standards for engines installed on new non-road mobile machinery have been organised as progressively more stringent tiers – also known as Stage I…V Standards. The latest standard – Stage V was adopted by Regulation (EU) 2016/1628 and applies to propulsion and auxiliary engines above 19 kW of all types of ignition for use in inland waterway vessels. The NOx and HC limits are harmonised with the U.S. standards for marine engines.

Engine Net power (P)NOxHCCOPM massPNMarket placement date
P ≥ 3001.×10121 January 2020
130 ≤ P < 3002. January 2019
75 ≤ P < 1305.4*5.00.141 January 2019
19 ≤ P < 754.7*5.00.31 January 2019

Read more about the Stage V standards.


U.S.: EPA Tier 4 marine engine standards

The regulation signed on March 14, 2008 and adopted by the United States Environmental Protection Agency (EPA), introduced two additional tiers of exhaust emissions standards – Tier 3 and Tier 4 – which apply to both newly manufactured and remanufactured marine diesel engines installed on U.S. Vessels.
The Tier 4 emission standards introduced a more stringent set of limits to exhaust gases such as NOx, HC and PM, for diesel engines above 600 kW (800 hp) on commercial vessels (see table below for details) and are based on the model year of the marine engine. Notably, this is the first tier that introduced a NOx limit for commercial vessels in the U.S.

Engine power (P)NOxHCPMApplies from model year
P ≥ 37001.80.190.12*2014**
2000 ≤ P < 37001.80.190.042014*
1400 ≤ P < 20001.80.190.042016*
600 ≤ P < 14001.80.190.042017*
*some exceptions apply

Read more about the U.S. EPA Federal Marine compression-ignition engines: exhaust emission standards.