Air Pollution from Ships

Emissions from ships are an important source of air pollutants including sulphur dioxide (SO2) and nitrogen oxides (NOx). The main statutory instruments controlling emissions at the international; European and UK level are listed below.

International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto (MARPOL)

The MARPOL Convention is the main international convention covering prevention of pollution of the marine environment by ships from operational or accidental causes. It is a combination of two treaties adopted in 1973 and 1978 respectively and updated by amendments through the years.

Annex VI covers the “Prevention ofAir Pollution from Ships”. The regulations in this annex set limits on sulphur oxide and nitrogen oxide emissions from ship exhausts and prohibit deliberate emissions of ozone depleting substances.

Sulpur Content of Marine fuels (SCMF) Directive (2005/33/EC)

Emissions of SO2 from the maritime sector in Europe are projected to surpass total emissions from all land-based sources by 2020 according to the European Commission’s Clean Air for Europe (CAFE) emission estimates, assuming no action is taken. This is due in a large part to considerable reductions made by shoreside industry and other terrestrial sources.
To address the significant health and environmental impacts of ship emissions, the Commission adopted an EU strategy in November 2002 to reduce such emissions.
The strategy resulted in an amendment of the SCLF Directive to include new sulphur content limits for marine fuels. The amended Directive, known as the Sulphur Content of Marine Fuels (SCMF) Directive (2005/33/EC) came into force in July 2005.
The basic obligations of the SCMF Directive included:

  • A 1.5% sulphur limit for fuels used by all ships in the SOx Emission Control Areas of the Baltic Sea and the North Sea and English Channel;
  • A 1.5% sulphur limit for fuels used by passenger ships on regular services between EU ports;
  • A ban on the marketing of marine diesel oils with sulphur content exceeding 1.5% by mass; and
  • A ban on the marketing of marine gas oils with sulphur content exceeding 0.1% by mass, from 1 January 2010.


As an alternative to the use of low sulphur marine fuels to comply with Articles 4a and 4b of the Directive, member states can allow trials of unapproved and, use of approved, emission abatement technologies as an alternative to low sulphur fuel provided that these ships:

‘…continuously achieve emission reductions which are at least equivalent to those which would be achieved through the limits on sulphur in fuel specified in this Directive.’ (Article 4c, paragraph 4)

The Merchant Shipping (Prevention of Air Pollution from Ships) (Amendment) Regulations 2010

These Regulations amend the Merchant Shipping (Prevention of Air Pollution from Ships) Regulations 2008 (S.I. 2008/2924) (the ‘2008 Regulations’) and implement the marine fuel elements of the Sulphur Content of Liquid Fuels Directive, 1999/32/EC relating to a reduction in the sulphur content of certain liquid fuels, as amended by Directive 2005/33/EC (1999/32/EC as amended henceforth referred to as “the Directive”).

The UK is a party to Annex VI of the MARPOL Convention which contains provisions on the sulphur content of liquid fuels and is implemented by the 2008 Regulations.

The Directive, which also includes provision on the sulphur content of liquid fuels, places additional requirements on shipping operating within the European Union. These Regulations, which implement the Directive, only give effect to the requirements within the Directive insofar as they relate to marine fuels, which are not duplicated under Annex VI.

The heavy fuel oil land based elements of the Directive are now implemented in the following regulations: - the Sulphur Content of Liquid Fuels (England and Wales) Regulations 2007 (S.I. 2007/79), the Sulphur Content of Liquid Fuels (Northern Ireland) Regulations 2007 (S.R. 2007/272), the Sulphur Content of Liquid Fuels (Scotland) Regulations 2007 (SS.I. 2007/27).

The Regulations deal with: –

  • sulphur content of marine fuels used in sulphur oxide emission control areas;
  • sulphur content of marine fuels used by passenger ships operating on regular services to or from Community ports;
  • sulphur content of marine fuels used by inland waterway vessels and ships at berth in Community ports;
  • the marketing of marine diesel oils with sulphur content exceeding 1.5% by mass;
  • the marketing of marine gas oils with sulphur content exceeding 0.1% by mass; and
  • trials and use of emission abatement technologies.


Further information
MARPOL Convention
European Union Strategy to reduce atmospheric emissions from seagoing ships
Sulphur Content of Marine Fuels Directive
The Merchant Shipping (Prevention of Air Pollution from Ships) (Amendment) Regulations 2010

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