SO2 emissions from ships in Europe

In response to concerns over the contribution of international shipping to air pollution, during the 1990s, the International Maritime Organization of the United Nations developed an annex to the MARPOL Convention covering air pollution from ships (Annex VI).

This Annex incorporates the concept of SOx Emission Control Areas or SECAs. Under its provisions, when ships operate in, or pass through such areas, they are required to use a fuel with a sulphur content of 1.5% m/m or less. Outside SECAs the sulphur content is limited to 4.5% m/m. For a sea area to be designated as a SECA, an application has to be made to the IMO, including a detailed environmental and cost effectiveness justification in accordance with specific criteria laid down in Annex VI.

To date the Baltic and North Seas are designated SECAs but the requirements will not be binding until Annex VI, signed by parties to the MARPOL Convention in September 1999, has been ratified.