Atmospheric Science Climate Change Human Health Pollution

MARPOL-ling in the Right Direction

Posted by Steven Koch

Research article: Zetterdahl, M., Jana Moldanov, J., Xiangyu Pei, X., Pathak, R. K., Demirdjian, B. (2016). Impact of the 0.1% fuel sulfur content limit in SECA on particle and gaseous emissions from marine vessels. Elseveir, Atmospheric Environment, 145 (2016) 338-345. doi:


Air pollution is an important issue that adversely affects the entirety of the global population causing severe health complications, forcing wildlife to change habitats, and contributing to climate change.  The continued heavy reliance on burning  fossil fuels serves as the main culprit driving air pollution. The bright side is that not all of the news is negative. I have found some revolutionary research on emissions control measures which is sure to provide optimistic insight on current international endeavors combating climate change. The basis of this fantastic revelation originates from a recent publication evaluating the impact of mandatory emissions reduction strategies prescribed by the International Convention for the Prevention of Pollution from Ships (MARPOL).

International Action

MARPOL was developed by the International Maritime Organization (IMO), the regulatory body responsible for establishing environmental, safety, and security regulations for the shipping industry. MARPOL prescribes specific preventative measures addressing air, oil, garbage, sewage, and harmful substances pollution to 154 signatory nations, i.e., nations which have accepted and agreed to follow the MARPOL regulations, operating vessels globally. Air pollution, which is Annex VI of MARPOL, outlines the proactive emissions reduction strategies as well as established sulfur emission control areas (SECAs) in several parts of the world. As of Jan 1, 2015, vessels subject to the regulations of Annex VI of MARPOL (Figure 1) were required to burn low sulfur fuel with a 0.1% sulfur content when transiting within a SECA.

Container Ship Departing New York Harbor
Figure 1- Container ship departing New York harbor. (

The reasoning behind the targeted campaign against sulfur is while a vessel is transiting within a SECA, it will inevitably encounter more coastal areas and their population, increasing the chance of exposure to sulfur oxides (SOx). The mandated lower sulfur concentration is intended to limit crewmember and community exposure in addition to reducing the acidification of soils and freshwater (Zetteral et al., 2016). SECAs currently enforced include the Baltic Sea, the North Sea, the English Channel, and coastal waters around the U.S., Canada, and the U.S. Caribbean Sea. The area a SECA spans varies between geographic regions. To put that into perspective, the U.S. SECA (Figure 2) is roughly equivalent to the 200 mile exclusive economic zone (EEZ). Regulatory enforcement of the U.S. SECA is a joint collaboration between the U.S. Environmental Protection Agency (EPA) and U.S. Coast Guard (USCG).

Figure 2- A map depicting the established SECAs.(

A drawback to this strategy occurs when vessels are operating outside of a SECA, i.e., the open ocean, where fuel sulfur content is allowed to be as high as 3.5%. Luckily, this regulation is set to change on Jan 1, 2020, when the mandated limit for open ocean sulfur content is reduced to 0.5%. In the meantime, many vessels carry both low and high sulfur fuels with established change-over procedures for entering or departing a SECA. The carriage of both types of sulfur fuels is simply a matter of cost. 0.1% fuel oil is more refined or “filtered” than high sulfur fuel oils. The more refining fuel oil undergoes to reduce sulfur content and impurities, the higher the production costs.

Positive Outlook

The authors of this paper explored the effectiveness of one SECA in particular: the Baltic Sea. They followed one vessel during two phases of operation; phase one was conducted prior to the January 1, 2015 0.1% implementation date in November 2014; phase two in April 2015. The vessel operated on 0.5 % sulfur fuel oil in November 2014 and 0.1% sulfur fuel oil in April 2015. To gather the best data encompassing every performance capability, the vessel was powered under three different modes of operation: high, medium, and low. An easy way to equate these operational levels is to compare them to driving a car: the high mode would be like driving on a highway, medium would be local travel in a town, and low would be at idle. The authors used direct measurements of funnel (smokestack) emissions and analyzed the exhaust for several different types of chemicals which included carbon (C), SOx, nitrous oxides (NOx), ash, and particulate matter. This experiment yielded some pretty amazing results. Particulate matter was significantly reduced by an incredible 67% when burning the 0.1% fuel. Even more impressive, the results of the observed SOx data yielded a phenomenal 80% reduction! In addition, the low sulfur fuel led to an overall reduction in total volatile organic compounds (VOCs). This evidence is even more compelling when you apply these results to the thousands of vessels worldwide that are required to meet the SECA regulations.

 A Personal Touch

I am extremely fortunate to have reviewed this research from a unique prospective; not only as a graduate student, but also as a Coast Guard inspector who has conducted numerous MARPOL examinations verifying SECA compliance onboard vessels. This process necessitated a thorough analysis of vessel fuel oil logs, fuel oil transfer procedures, and safety management systems. In a few cases, vessels found to be in violation of the SECA requirements were restricted to port and denied departure until compliant fuel (< 0.1%) was obtained. This research was such a breath of fresh air showcasing just how effective a coordinated effort between international regulatory bodies and the shipping industry has been in substantially reducing SOx and other chemical emissions from ships. This cooperative model would be extremely valuable and useful in many other emission reduction applications.

Leave a Reply

Your email address will not be published.