Ατμοσφαιρική ρύπανση από πλοία : Διεθνείς και ευρωπαϊκές εξελίξεις
Ocean-going shipping provides an important means of transporting goods internationally, as well as enabling other activities such as fishing, leisure transport etc. Today the majority of the global fleet uses diesel engines as a means of providing propulsive power for ships. The principal pollutants produced by navigation are a consequence of combusting the fuel in internal combustion (marine) engines. These are pollutants (CO, VOC, NOx and PM) which mainly have to do with engine technology, and pollutants (CO2, SOx, heavy metals and sulphate-derived PM) which originate from the fuel speciation. Shipping is a small contributor to the world total CO2 emissions (1.8% of world total CO2 emissions in 1996). On a European scale, SO2 and NOx emissions from national shipping can be important with respect to total national emissions. The principal legislative instrument for exhaust emissions from ships Marpol Annex VI (Tier I with Tier II and Tier III amendments adopted by IMO) controls NOx limits and sulphur oxides, through sulphur in fuel and further through the designation of Sulphur Dioxide Emission Control Area (SECA). The measures in Marpol Annex VI describe the outcomes, they do not stipulate how they are to be achieved. Technology for controlling emissions from ships includes improved engine design, fuel injection systems, electronic timing, etc. to obtain optimum efficiency (optimising CO2 emissions) reducing PM and VOC emissions. Exhaust gas recirculation (EGR) technique and air pollution control technologies (scrubbers, etc) have not yet been in regular service for ships. The EU emissions trading system (EU ETS) does not cover CO2 emissions from shipping although it covers CO2 emissions from flights within and between countries participating in the EU ETS and international flights to and from non-ETS countries. The emission legislation limits for diesel engines for recreational craft (Directive 2003/44) are not mentioned in this paper. Accordingly, much effort is still needed in the direction of reducing the exhaust emissions from shipping adjusting current Environmental Regulations and current air pollution control technologies.