As 31st August 2017 a marine diesel engine that is installed on a ship constructed on or after this date shall comply with the Tier III NOx standards if the ship is operating within ECAs or at least shall comply with Tier II NOx Standard if it is operating outside ECAs.

The control of diesel engine NOx emissions is achieved through the survey and certification requirements leading to the issue of an Engine International Air Pollution Prevention (EIAPP) Certificate and the subsequent demonstration of in service compliance in accordance with the requirements of the mandatory, regulations 13.8 and 5.3.2 respectively, NOx Technical Code 2008 (resolution MEPC.177(58) as amended by resolution MEPC.251.(66)).

And what about ECAs? Emission Control Areas (ECAs) are sea areas in which stricter controls were established to minimize airborne emissions (SOx, NOx, ODS, VOC) from ships as defined by Annex VI of the 1997 MARPOL Protocol which came into effect in May 2005. As of 2011 existing ECAs include the Baltic Sea(SOx, adopted 1997; enforced 2005) and the North Sea (SOx, 2005/2006 adopted July 2005; enforced 2006), the North American ECA, including most of US and Canadian coast (NOx & SOx, 2010/2012) and the US Caribbean ECA, including Puerto Rico and the US Virgin Islands (NOx & SOx, 2011/2014).

All those controls are necessary because ocean going vessels emit significant pollution that not only effect populations living near ports and coastlines, but also those living hundreds of miles inland. Marine diesel engines generate significant emissions of NOx, fine particulate matter (PM2.5), and sulfur oxides (SOx) that are associated with adverse health effects. Emissions from these engines also cause harm to public welfare, and contribute to visibility impairment and other detrimental environmental impacts across each country.

Large marine diesel engines are significant contributors to our national mobile source emission inventory and their contribution is expected to grow in the future. At the current rate, NOx emissions from ships are projected to more than double while annual PM2.5 emissions are expected to almost triple by 2030.