The primary regulation that is reducing ship emissions in Prince Williams Sound is the International Maritime Organization (IMO) International Convention for the Prevention of Pollution from Ships Annex VI (MARPOL Annex VI) and its amendments, under which the North American Emissions Control Area (ECA) was established. Prince William Sound is within the North American ECA, which has both fuel sulfur content requirements and advanced oxides of nitrogen (NOx) standards for marine diesel engines on ships with a keel laid date on or after 1 January 2016. In this study, the emissions reductions are estimated as a result of the lower sulfur fuel requirements and the NOx marine diesel engine standards applicable to the fleet calling Prince Williams Sound.
See also newsletter article on the results of this report: Report shows air pollutants in Prince William Sound reduced by hundreds of tons per year