Sulphur and nitrogen oxide emissions

One of shipping’s main environmental impacts is emissions of sulphur and nitrogen oxides. In addition to health risks, the emissions also contribute to eutrophication and  acidification of forests, soil and water.   

Sulphur oxides

Sulphur is naturally contained in all crude oils and is converted into sulphur dioxide on combustion. The amount of sulphur dioxide released during combustion of sulphur-containing fuel is proportional to the amount of sulphur in the fuel. The sulphur content of the fuel affects the emissions in several different ways. In addition to determining the amount of sulphur dioxide released, the sulphur content also affects emissions of particles and nitrogen oxides. 

Maximum sulphur content may differ according to a vessel’s location. With effect from 1 January 2015, the sulphur content of fuel may not exceed 0.1% m/m in sulphur emission control areas (SECAs). These areas include the Baltic Sea, North Sea, English Channel, Canada and the United States. With the introduction of IMO 2020 on 1 January 2020, the limit outside SECA was reduced from 3.5 to 0.5 percent m/m. To meet the requirements, a transition to low sulphur marine fuels or use of alternative fuels (e.g., LNG or methanol) is necessary. In addition, the regulations have also been an incentive to install scrubbers that clean exhaust gases during use of highsulphur fuel. 

Concordia Maritime has decided against investing in scrubbers, but has switched to low-sulphur fuels instead.

Nitrogen oxides

Nitrogen oxides are formed during combustion of bunker oil. As a result of stricter regulations and companies’ own improvement efforts, there has been a significant  reduction in emissions of nitrogen oxides from shipping in recent years. The current emission limit values for nitrogen oxides are controlled by when the diesel engine was manufactured and when the vessel was built.

All remaining vessels in Concordia Maritime’s fleet meet the IMO’s Tier I standards.