Air pollution is one of the most challenging environmental issues; it is global, long term, and its mitigation will involve major social and technological choices. Air pollution causes damages and imposes risks on human beings and ecosystems. In the European Union (EU) only for the year 2010, annual premature mortalities due to poor air quality amounted to over 400,000. The major air pollutants are particulate matter (PM), sulphur and nitrogen oxides (SOx and NOx respectively). NOx and SOx are typically emitted by road vehicles, shipping, industry and households, and they both influence human health through the formation of secondary PM, simultaneously contributing to acid rain, eutrophication effects, and also being key components in increased levels of ground-level ozone. PM is fine dust emitted mainly by road vehicles, shipping and power generation and from natural sources such as sea salt, wind-blown soil and sand. It can cause respiratory and cardiovascular diseases, and lung cancer. Data from several epidemiological surveys highlight that an increase in atmospheric concentration of PM10 (particles with a diameter of up to 10 micrometers) by 10 μg/m3, will result to a total mortality increase by 0.5%, while there will be an increase in emergency hospital admission events due to cardiovascular and respiratory diseases by about 0.5% and 1% respectively. Even more dangerous are the PM2.5, as for every additional 1 mg emitted the number of premature deaths will rise by 0.6-1.6% per year. Air pollution also brings significant economic costs due to the reduction in productivity (lost work days), and additional medical costs of healthcare. The relative economic costs for hospitalization are estimated to 3-9% of EU GDP (€330-940 billion, in 2010 values).
In the year 2000, emissions from maritime international shipping in the seas surrounding the EU were between 20% and 30% of the land-based emissions, while for the 2020 (under business-as-usual scenarios) these are expected to be almost equal. Although in-port emissions constitute a small percentage of the overall shipping emissions, the continuously increasing amount of goods and passengers transported between ports during the last years (due to the growth of international trade and the improved living standards of various countries) have led to increased pollution in ports (from ships and other port related anthropogenic means). Due to their role, ports inevitably concentrate shipping traffic and ship exhaust emissions and thus their environmental effects have raised concerns regarding the induced costs and negative effects on local air quality. In harbour cities or coastal areas, ship emissions are often the dominant source of urban pollution. Significant studies have been conducted regarding the impact of ship exhaust pollutants (mainly NOx, SOx and PM) upon the health of human population near port areas. The induced costs of these emissions are practically addressed primarily by the local society which will have to pay in due time the consequences (either in people's health or in local infrastructures).
The School of Production Engineering and Management of Technical University of Crete, in Greece, in collaboration with the Research Centre of Energy Management of ESCP Europe Business School, have estimated the anticipated economic costs (due to air pollutants effects) that will be paid either by local authorities or citizens, who live and work in areas close to ports. Specifically, the survey focused on the external costs caused by maritime air pollution (NOx, SOx and PM), during the manoeuvring, hoteling and at berth processes of ships in ports. Three internationally recognised methodologies, BETA, CAFE CBA and HEATCO have been employed for the calculation of the induced external costs. Through these methodologies various factors are taken into account (e.g. weather conditions per period of the year, population density by country, distribution and source of pollutants, etc) and specific weighting factors for each pollutant per country are calculated.
Unsurprisingly, ports with increased commercial activity exhibit the highest external costs. Port of Antwerp is a typical case, as its total external cost ranges from 475 to 1.850 million €, depending on the selected methodology, while for Rotterdam (Netherland's largest port) the cost ranges from 80 to 215 million €. For Piraeus (the largest passenger port in EU) the minimum expected cost was €3 million while the maximum, according to BETA methodology, was raised to €33 million. The case of Piraeus represents a great social-environmental-economic interest, as due to the high population density (16,000 citizens per km2) and the large amount of air emissions, the anticipated health impacts and the total offset cost per habitant will be extremely high. The cases of less "active" ports (both in terms commercial load and passengers' movements) have also been studied. Copenhagen and Aberdeen are such cases: the total external costs have been estimated from 2-7 million € for the former, while for the port of Aberdeen 2 to 4 million €. From all studied EU ports, the lowest external cost was estimated in the port of Koge (Denmark), being less than €300.000 per year.
The European Commission has already recognized the importance of the above, and aims at setting mandatory monitoring and recording of air emissions of all ships approaching EU ports. In addition, measures towards the mitigation of air pollution and improvement of the air quality in cities by 2030 have been adopted. These measures include:i.a revised National Emission Ceilings Directive, with stricter limits for the main air pollutants;ii.a new Clean Air Programme for Europe with additional measures aiming for the existing targets and new air quality objectives for the period up to 2030;iii.a proposal for a new Directive to reduce air pollution from medium-sized combustion installations (energy plants, large buildings, small industries).
Due to the proposed new clean air policy package it is estimated that by 2030 about 58,000 premature deaths will be avoided, while health benefits alone will save €40-140 billion in external costs and provide about €3 billion in direct benefits due to higher productivity of the workforce. The direct cost of the necessary measures in order to reduce air pollution by 2030, is estimated at €3.4 billion per year, while the direct gain from the benefits to people's health from the implementation of the proposed measures will be around €40 billion per year (i.e. almost 12 times higher than the pollution abatement costs).