Introduction to marine emissions

Version history

February 2024  Rev. 0.1 – Page 2 and bookmarking updated; no change to content

December 2016 – Initial publication


Shipping faces lower emission limits to air from machinery. These emission limits are primarily concerned with oxides of sulphur (SOX) and oxides of nitrogen (NOX) with particulate matter (PM) under discussion. There are efforts to analyse and quantify carbon dioxide (CO2) emissions from shipping which may lead to future emissions controls. Shipping is moving closer to a land-based industry which has been subject to emissions controls for many years.

There are a variety of possible strategies available to operators to meet emissions limits. These include using fuels which produce lower emissions or using emissions abatement technologies. Low sulphur fuels address SOX emissions but may not meet NOX emissions limits without abatement techniques. This guidance is intended to assist members in considering the implications of emissions regulation and to support informed decision making when developing compliance strategies.

A number of specialised terms are used in this document. It is assumed that readers are familiar with most of them. However, a number of them, although in use for many years, could be misunderstood. These terms are defined below to ensure that readers understand what is meant by them in this document.


  • Introduction
  • Glossary
  • Emissions Reduction Regulations
  • MARPOL VI SOX and NOX Compliance Options
  • Emissions Compliance Implementation
  • Questions and Answers
Reference(s): IMCA M239, IMCA REG002
Published:February 2024
Grade:IMCA Informative Guidance

Members should log in to access downloads
and discounted pricing on physical items.