Evaluation of applied provisions and technologies on ship emission and air quality

Although perceived as the most environmentally friendly means of transport, ships are a significant source of pollution to the environment. The vast majority of emissions in EU sea areas are emitted from cargo ships over 500 GT. About 45% of all emissions come from EU flagged ships and approximately 20% of emissions are emitted within the 12-mile limit of territorial seas. In port cities, ship emissions are in many cases a dominant source of pollution and need to be addressed when considering compliance with legally binding air quality objectives. Moreover, emissions from ships travel over hundreds of kilometres and can thus contribute to air quality problems on land even if they are emitted at sea. This is particularly relevant for the deposition of sulphur and nitrogen compounds, which cause acidification of natural ecosystems and threaten biodiversity through excessive nitrogen inputs. Emission of toxic compounds in marine engines exhausts is limited by international legal provisions, namely MARPOL convention, which in Annex VI sets limits to SOx and NOx emissions and designates special areas where the limits are stringent. To comply with the provisions, marine vessels need to be equipped with installations reducing emissions to permissible levels or turn to alternative fuels. The paper presents evaluation of impact of those having been in force for the last decade limitations as well as of applied new technological solutions on improvement of air quality. The analysis was conducted for the Baltic Sea, based on available data on ship traffic in the area and emission factors.