IMO regulations to reduce sulphur oxides (SOx) emissions from ships first came into force in 2005, under Annex VI of the International Convention for the Prevention of Pollution from Ships (known as the MARPOL Convention).. Since then, the limits on sulphur oxides have been progressively tightened.
The main type of “bunker” oil for ships is heavy fuel oil, derived as a residue from crude oil distillation. Crude oil contains sulphur which, following combustion in the engine, ends up in ship emissions. Sulphur oxides (SOx) are known to be harmful to human health, causing respiratory symptoms and lung disease. In the atmosphere, SOx can lead to acid rain, which can harm crops, forests and aquatic species, and contributes to the acidification of the oceans.
Limiting SOx emissions from ships will improve air quality and protects the environment.
From 1 January 2020, the limit for sulphur in fuel oil used on board ships operating outside designated emission control areas will be reduced to 0.50% m/m (mass by mass). This will significantly reduce the amount of sulphur oxides emanating from ships and should have major health and environmental benefits for the world, particularly for populations living close to ports and coasts.
Below you will find answers to some of the frequently asked questions about the sulphur limit.
Limiting SOx emissions from ships will have a very positive impact on human health: how does that work?
Simply put, limiting sulphur oxides emissions from ships reduces air pollution and results in a cleaner environment. Reducing SOx also reduces particulate matter, tiny harmful particles which form when fuel is burnt.
A study on the human health impacts of SOx emissions from ships, submitted to IMO’s Marine Environment Protection Committee (MEPC) in 2016 by Finland, estimated that by not reducing the SOx limit for ships from 2020, the air pollution from ships would contribute to more than 570,000 additional premature deaths worldwide between 2020-2025.
So a reduction in the limit for sulphur in fuel oil used on board ships will have tangible health benefits, particularly for populations living close to ports and major shipping routes.
What is the current regulation on SOx in ships emissions and by how much is that going to be improved?
We are going to see a substantial cut: to 0.50% m/m (mass by mass) from 3.50% m/m.
For ships operating outside designated emission control areas the current limit for sulphur content of ships’ fuel oil is 3.50% m/m.
The new limit will be 0.50% m/m which will apply on and after 1 January 2020.
There is an even stricter limit of 0.10% m/m already in effect in emission control areas (ECAS) which have been established by IMO. This 0.10% m/m limit applies in the four established ECAS: the Baltic Sea area; the North Sea area; the North American area (covering designated coastal areas off the United States and Canada); and the United States Caribbean Sea area (around Puerto Rico and the United States Virgin Islands).
Fuel oil providers already supply fuel oil which meets the 0.10% m/m limit (such as marine distillate and ultra low sulphur fuel oil blends) to ships which require this fuel to trade in the ECAs.
What must ships do to meet the new IMO regulations?
The IMO MARPOL regulations limit the sulphur content in fuel oil. So ships need to use fuel oil which is inherently low enough in sulphur, in order to meet IMO requirements.
Some ships limit the air pollutants by installing exhaust gas cleaning systems, also known as “scrubbers”. This is accepted by flag States as an alternative means to meet the sulphur limit requirement.
Ships can have engines which can use different fuels, which may contain low or zero sulphur. For example, liquefied natural gas, or biofuels.
Could the 0.50% limit be delayed?
No. There can be no change in the 1 January 2020 implementation date, as it is too late now to amend the date and for any revised date to enter into force before 1 January 2020.
Copyright: International Maritime Organization (IMO)