Emissions of air pollutants like sulphur dioxide can travel long distances. In recent years, emissions from maritime transport have increasingly affected air quality in the EU. Sulphur dioxide emissions cause acid rain and combine with other pollutants to generate fine particles. This particulate matter contributes to the overall PM2,5 air pollution burden in the EU.

As of 1 January 2015, EU Member States have to ensure that ships in the Baltic, the North Sea and the English Channel use fuels with a sulphur content of no more than 0.10%. This is the so called SOx-Emission Control Area (SOx-ECA) requirement which applies also under international law in virtue of the designation of those sea areas as SOx-ECAs under the MARPOL Convention (the international Convention for the Prevention of Pollution from Ships). Higher sulphur contents are still possible, but only if sustainable exhaust cleaning systems are installed on board.

As of 1 January 2020, EU Member States will also have to ensure that ships in all EU waters except SOx-ECAs use fuels with a sulphur content of no more than 0.5%. The same requirement, also called the global sulphur cap, will also enter into force globally as decided in October 2016 by the International Maritime Organization (IMO), a United Nations specialised agency and governing body for the MARPOL Convention. This landmark decision will significantly reduce the impact of ship emissions on human health and ensure a global level playing field for ship operators.

The codified legislation addressing sulphur oxides emissions from shipping in the EU is Directive (EU) 2016/802 regulating the sulphur content of certain liquid fuels. It contains the latest limits for marine fuels mentioned above which were introduced by Directive 2012/33/EU amending Directive Directive 1999/32/EC, and is the result of a sustained period of legislative development.

Back in 2005, the European Commission's thematic strategy on air pollution concluded that without further action, sulphur emissions from shipping would exceed those from all land-based sources in the EU by 2020 (Source: Clean Air for Europe impact assessment, 2005). Further action was therefore needed to improve human health and the environment. As shipping is an international industry, environmental, security and safety standards are generally developed by the IMO. Directive 1999/32/EC was amended in 2005 by Directive 2005/33/EC to reflect the provisions of Annex VI of IMO's Marine Pollution Convention, MARPOL 73/78. Under these provisions, the Baltic, the North Sea and the English Channel were designated as SOx-ECAs, with the corresponding obligation to limit the sulphur content of fuel used in those areas to 1,5%. In October 2008 an amended Annex VI to the MARPOL Convention was adopted, further lowering the maximum permissible sulphur content of marine fuels inside and outside of SOx –ECAs . EU law was aligned to the new MARPOL limits in 2012 by means of Directive 2012/33/EU. In both the 2005 and 2012 amendments of the Directive, the fuel sulphur standards were also applied to passenger ships operating a regular service outside the SOx-ECAs.

Since 2013 technical work has been ongoing under the European Sustainable Shipping Forum to discuss coordinated strategies to ensure a cost-effective implementation of the amendments introduced by Directive 2012/33/EU. The Forum is chaired by the Commission with the participation of the EU Member States, the maritime industry and the technical assistance of the European Maritime Safety Agency. On the basis of that work Commission Implementing Decision 2015/253 was adopted to support the intensification of sulphur in fuel inspections in EU ports, setting methodologies for on board sampling for optimal verification of the sulphur content, and streamlining the related reporting requirements for the EU member States. The decision launched the Union Information system (Thetis-EU), which was developed by EMSA and endorsed by all EU coastal states for use on a voluntary basis, for introducing and sharing results of authorities' inspections and enforcement actions on individual ships. Thetis-EU allows reliable assessment of EU compliance under the Sulphur Directive and sets an internationally recognised best practice example of smart enforcement, including for the onboard inspections guidelines. THETIS-EU has the potential for inspection targeting based on risk including alerts from remote sensing and fuel calculator inspection tools.

In October 2016, the IMO introduced two new NOx Emission Control Areas: the Baltic Sea and the North Sea. As of 1 January 2021, all ships passing through these NOx Emission Control Areas must use defined mandatory engine standards or equivalent NOx emission reduction technologies to respect the stricter NOx emission levels (Tier III of the IMO NOx regulations – aiming to reduce nitrogen oxide emissions by approximately 70 per cent compared with the Tier II standards).

Useful links regarding pollutant emissions from ships