The air quality measurements were carried out using an automated monitoring station on the cruise ship Costa Pacifica which followed a fixed weekly route in the Western Mediterranean during 2009 and 2010.

The concentrations of sulfur dioxide were found to decrease significantly in three out of the four Mediterranean EU harbors that were investigated: Civitavecchia, Savona and Palma de Mallorca; the daily mean concentrations in all of the harbors decreased on average by 66%. JRC measurements in the harbor of Barcelona were inconclusive because of large day-to-day concentration variations. However, independent measurements from monitoring stations in the harbor of Barcelona and in the vicinity of the harbor of Palma de Mallorca confirm a strong decrease in sulfur dioxide concentrations from 2009 to 2010.

In contrast, no decrease in sulfur dioxide was observed in the Mediterranean harbor of Tunis, and there was no reduction in any of the other air pollutants that were measured in all four harbors (Civitavecchia, Savona, Palma de Mallorca and Tunis). This shows that the decreases in sulfur dioxide are a direct consequence of the application of the EU requirements. The study also confirms a correlation between sulfur dioxide and chemical elements typically emitted from ship stacks which demonstrates that ships were the main source of sulfur dioxide in the harbors.

Sulphur dioxide is one of the main chemicals responsible for formation of acid rain and particulate air pollution—a major risk factor for cardiovascular and respiratory diseases. The 2005 amendment of Directive 1999/32/EC required that, as of January 2010, all ships at berth or at anchor in European harbors use fuels with a sulfur content of less than 0.1% by weight, while previously, outside of Sulphur Emission Control Areas, a sulphur content of up to 4.5% was allowed.

Ships traditionally use heavy fuel oil which, from 2012, can have a sulfur content of up to 3.5% for cargo vessels (before 2012 this limit was 4.5%). The average sulfur content of heavy fuel oil is about 2.4%. By comparison, the sulphur content of fuels used in road vehicles must not exceed 0.001%.

In line with the broader environmental protection objectives of the EU and strengthening a parallel agreement reached by the International Maritime Organisation, the European Parliament and the Council have come to an agreement to be submitted to formal vote after the summer on an amendment to the 1999/32/EC directive to further reduce sulphur content of fuels used outside of harbors.

The maximum allowed sulphur content of ship fuels will go down from 3.5% to 0.5% in 2020, and in the Sulfur Emission Control Areas (the Baltic Sea, the North Sea and the English Channel) the current limit of 1.5% sulphur content for ship fuels will be reduced to 0.1% in 2015.

The logistics for the automated ship-borne monitoring station for air pollutants used in this work were provided by Costa Crociere and the measurements were performed in collaboration with scientists from the Universities of Genoa and Florence, the INFN-LABEC Laboratory in Florence as well as from the Institute of Environmental Assessment and Water Research in Barcelona.

The results of the study, entitled “Impact of a European directive on ship emissions on air quality in Mediterranean harbours”, have been published in the journal Atmospheric Environment.

Resources

• C. Schembari, F. Cavalli, E. Cuccia, J. Hjorth, G. Calzolai., N. Pérez, J. Pey, P. Prati, F. Raes (2012) Impact of a European directive on ship emissions on air quality in Mediterranean harbors, Atmospheric Environment doi: 10.1016/j.atmosenv.2012.06.047