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Air Pollution in Shipping: The Further Reduction of S02 Emissions 2020

As of January 2020, the International Maritime Organisation (IMO), in line with the International Convention for the Prevention of Pollution from Ships (MARPOL) will set new limits on the sulphur content in fuel oils on board vessels.

Even though ships are known to be some of the largest and most reliable machines on the planet, they emit around 1000 million tonnes of C02 annually and are responsible for approximately 2.5% of global greenhouse gas emissions. One of the main and most harmful chemical pollutants in this field is Sulphur Dioxide (SO2), which is regularly emitted into the atmosphere as a result of the combustion of fuels containing sulphur. Between 2007 and 2012, the IMO reported that approximately 11.3 million tonnes of Sulphur dioxide were generated annually by the maritime transport industry.[1]

Sulphur dioxide is a pollutant that contributes to acid deposition, which in turn, can lead to potential changes in soil and water quality. The subsequent impacts of acid deposition can be significant, including adverse effects on aquatic ecosystems in rivers and lakes and damage to forests, crops and other vegetation. S02 also contributes to the formation of particulate aerosols in the atmosphere which can be tremendously harmful to human health and which may cause respiratory and cardiovascular complications whilst also reducing one’s life expectancy by up to two years.

To date, there has been a limitation of up to 3.50% m/m (mass by mass) sulphur content within fuels on board vessels operating outside the ‘Emission Control Areas’ (ECA). By means of comparison, the sulphur content of fuels used in trucks or passenger cars must not exceed 0.001%.[2] A study conducted in 2016 which explored the impacts on human health from S02 emissions from ships, submitted to the IMO’s Marine Environment Protection Committee (MEPC) by Finland, estimated that by not reducing the S02 limit from ships, the air pollution would contribute to more than 570,000 additional premature deaths worldwide between 2020 and 2025. 

As of the 1st of January 2020, the limit of sulphur present in fuel oil used on board ships operating outside designated emission control areas will be reduced to 0.50% m/m from the 3.50% limit previously imposed.[3]

This change will effectively impose an obligation on all ships, irrespective of size, to use fuel oils which are inherently low in sulphur, in order to meet the newly revised IMO standards. In certain circumstances, a number of exemptions are provided, for instance a) when the safety of the ship is at risk b) when there is a rescue operation underway, or c) if a ship or its equipment is damaged. Another exemption allows for a ship to conduct trials for the development of ship emission reduction and control technologies and engine design programmes. This would require a special permit from the respective Flag State of the vessel.

How can ship operators and owners plan ahead for the 0.50% sulphur 2020 limit?

The Marine Environment Protection Committee (MEPC) has approved guidance on ship implementation planning in order to assist ship operators and ship owners to plan ahead for the 0.50% sulphur restriction in 2020. The ship implementation planning guidance includes sections on:

  • risk assessment and mitigation plans (impact of new fuels);
  • fuel oil system modifications and tank cleaning (if needed);
  • fuel oil capacity and segregation capability;
  • procurement of compliant fuel;
  • fuel oil changeover plan (conventional residual fuel oils to 0.50% sulphur compliant fuel oil); and
  • documentation and reporting.

How is the IMO going to assure that such sulphur limits are being followed?

Monitoring, compliance and enforcement of the new limit falls to governments and national authorities of Member States that are Parties to MARPOL. Flag States and port States have rights and responsibilities to enforce such compliance. 

The IMO is working with Member States as well as the industry (including the shipping industry and the bunker supply and refining industry) to identify and mitigate transitional issues so that vessels may meet the new requirements, including developing guidance, developing standardised formats for reporting fuel oil non-availability if a ship cannot obtain compliant fuel oil and considering verification and control issues.

What controls will there be once the new global limit takes effect?

Vessels taking on fuel oil for use on board must obtain a bunker delivery note, which states the sulphur content of the fuel oil supplied. Vessels must also be issued with an International Air Pollution Prevention (IAPP) Certificate by their Flag State. This certificate includes a section stating that the ship uses fuel oil with a sulphur content that does not exceed the applicable limit value as documented by bunker delivery notes or uses an approved equivalent arrangement.

If the legal limits are not adhered to, sanctions may be imposed however it is up to the individual State Party to set its own sanctioning and fine mechanism.  

To conclude, a study conducted in 2016 which explored the impacts on human health from S02 emissions from ships, submitted to the IMO’s Marine Environment Protection Committee (MEPC) by Finland, estimated that by not reducing the S02 limit from ships, the air pollution would contribute to more than 570,000 additional premature deaths worldwide between 2020-2025. Therefore, the regulatory restriction on the limits of sulphur in fuels used to operate vessels will definitely contribute to a cleaner environment and a substantial improvement to one’s well-being.

Article written by Dr Sean Xerri de Caro

For more information on the new limitations on sulphur emissions in shipping commencing 2020, kindly contact Dr. Robert Tufigno on rtufigno@gtgadvocates.com or Dr. Sean Xerri de Caro on sxerridecaro@gtgadvocates.com.

This article is not intended to impart legal advice and readers are asked to seek verification of statements made before acting on them


[1] International Maritime Organisation, ‘Third IMO GHG Study 2014’ <http://www.imo.org/en/OurWork/Environment/PollutionPrevention/AirPollution/Pages/Greenhouse-Gas-Studies-2014.aspx>

[2] European Commission, ‘Concerted EU Action Reduces Air Pollution from Shipping in European Coastlines and Ports’, (2018) <https://ec.europa.eu/info/news/concerted-eu-action-reduces-air-pollution-shipping-european-coastlines-and-ports-2018-apr-12_en>

[3] International Maritime Organisation, ‘Sulphur 2020-Cutting Sulphur Oxide Emissions’ <http://www.imo.org/en/MediaCentre/HotTopics/Pages/Sulphur-2020.aspx