The use of scrubbers reduces the atmospheric emissions of SOX from ships but it is not zero. NOX is hardly affected. The emissions to the atmosphere (even if lower) will cause local and regional transport and deposition of the SOX, partly in the Baltic Sea. We will identify representative scenarios for future emissions of SOX and NOX from ships in the Baltic Sea (shipping scenarios), and model the consequent acid deposition to the sea surface.

The emissions of SOX and NOX from ship traffic have been and will be changing. This is due to changes in traffic quantity and changes in fuel and cleaning technique like scrubber systems. The first step is to quantify these changes by getting an overview of historical data and determine relevant future scenarios. Historical data of SOX emissions can be found in data bases but the ship emissions are not very well determined. Here we have to make qualified guesses of the ship contribution. Future emissions will be based on the shipping scenarios used in the TREMOVE European transport model with yearly increases of 2.5 % for cargo ships and 3.9% or 5 % for passenger ships according to DeCeuster (2006) and Stipa et al. (2007). After 2030 the shipping will be assumed constant. Three fuel scenarios will be used with different sulphur content, 1 %, 0.5 % and 0.1 % as seen from the atmospheric point of view.

The atmospheric transport and deposition of the emitted SOX and NOX will be modelled by the EMEP/MSC-W model (Simpson et al., 2012), a chemical transport model developed at the Meteorological Synthesizing Centre - West (MSC-W) at the Norwegian Meteorological Institute ( The model area covers Europe and NE Atlantic Ocean. It is a limited-area, terrain following sigma coordinate model with 20 vertical levels designed to calculate air concentration and deposition fields. The basic resolution is 50 km but nesting to finer resolution is supported and is needed for our study area. Gridded ship emissions are originally taken from ENTEC (now part of AMEC Environment Infrastructure,UK, and IIASA, and Cofala et al. (2007) and Jonson et al. (2009). These data will be modified according to the scenarios. Because of limited computer resources the modelling will be performed in "sliced" runs, meaning that we model 5 year periods in key sections of the period 1960–2050.

Figure 2. Spatial distribution of SO2 emissions from international shipping in the year 2000 used by the EMEP model.




Cofala, J., Amann, M., Hayes, C., Wagner, F., Klimont, Z., Posch, M., Schöpp, W., Tarrasón, L., Jonson, J.E., Whall, C. And Stavrakaki, A., 2007, Analysis of policy measures to reduce ship emissions in the context of the revision of national emission ceilings directive. International Institute for Applied Systems Analysis (IIASA), IIASA contract no. 06–107.

De Ceuster G., van Herbruggen B., Logghe S. (2006), TREMOVE - description of model and baseline version 2.41. Report for the European Commission, DG ENV. Chapter VI – The maritime model. Service Contract B4-3040/2002/342069/MAR/C.1. Transport & Mobility Leuven, Leuven, Belgium 

Jonson, J., Tarras´on, L., Klein, H., Vestreng, V., Cofala, J., and Whall, C.: Effects of ship emissions on European ground level ozone in 2020, Int. J. Remote Sens., 30, 4099–4110, doi:10.1080/01431160902821858, 2009.

Simpson, D., Benedictow, A., Berge, H., Bergström, R., Emberson, L. D., Fagerli, H., Flechard, C. R., Hayman, G. D., Gauss, M., Jonson, J. E., Jenkin, M. E., Nyíri, A., Richter, C., Semeena, V. S., Tsyro, S., Tuovinen, J.-P., Valdebenito, Á., and Wind, P.: The EMEP MSC-W chemical transport model – technical description, Atmos. Chem. Phys., 12, 7825-7865, doi:10.5194/acp-12-7825-2012, 2012.

Stipa, T., et al., Emissions of NOX from baltic shipping and first estimates of their effects on air quality and eutrophication of the Baltic Sea, ShipNOEm project report. 2007.