8.0 AIR QUALITY AT PORTS
8.0 AIR QUALITY AT PORTS
8.1 The National Atmospheric Emissions Inventory maps41 for NOx, PM10 and SOx show elevated levels along key shipping routes, including the IMO routes through the Minches and along the Atlantic coast of the Western Isles (Figures 8, 9 and 10), and routes in the Firths of Forth and the Clyde. Similar elevated levels can be seen in the Forth of Lorn showing routes from Oban, on routes to Orkney and Shetland, and on routes departing from/arriving at Aberdeen.
8.2 Atmospheric emissions from shipping are controlled at both international and European levels. Annex VI of the MARPOL Convention42 limits the level of NOx and SOx from engine emissions:
- NOx emissions are limited to between 17.0g/kWh and 7.7g/KWh depending on vessel age and engine rated speed. This is scheduled to be reduced further following a technical review in 2013.
- The North Sea is designated as an IMO Emission Control Area (ECA) for SOx. From 1 January 2012 SOx limits will be set at 3.50% m/m outside the ECA. Emissions of SOx are limited to 1.00% m/m within the ECA, and are set to fall to 0.10% m/m from January 2015.
The Sulphur Content of Liquid Fuels Directive43 as amended by Directive 2005/33/EC limits the sulphur content of fuel used by passenger ships to 1.5%.
8.3 Our domestic ferry fleet predominantly runs on marine gas oil, except a few routes (e.g. to Orkney and Shetland) which run on intermediate fuel oil.
8.4 Air pollution can have repercussions for many aspects of quality of life, including human health. Long term exposure to poor air quality is associated with a number of health complaints, including an increased risk of cardiopulmonary disease44 . Emissions from marine vessels have the potential to be felt in ports and the communities that surround them, due to the running of engines to provide onboard power whilst vessels are in dock.
8.5 Twenty-nine Air Quality Management Areas (AQMAs) are designated in Scotland.45 They are predominantly located inland, in urban areas, and are mainly linked to road-based transport. All are designated as a result of nitrous oxides (NOx) and particulate matter (PM10); the exception is the AQMA at Grangemouth, in an area encompassing a petrochemical complex, which is designated for sulphur oxides (SOx). Domestic ferries do not use the port at Grangemouth. The AQMA in Aberdeen City Centre borders the western boundary of Aberdeen Harbour and is designated for NOx and PM10.
Figure 8. UK Emissions Map of NOx 2009
Figure 9. UK Emissions Map of PM10 2009
Figure 10. UK Emissions Map of SO2 2009
8.6 The aim of AQMAs is to ensure that the national air quality objectives will be achieved by the relevant deadlines. The objectives have been set to protect human health and the environment. From the existing data, it would appear that emissions from shipping are not breaching the national air quality objectives.
8.7 Increased vessel traffic on existing routes, either by extending the length of the operating day or by increasing the frequency of services, will increase emissions of air pollutants. It is not expected that these increases will result in significant deteriorations in air quality at the national level. Legislative controls limit the sulphur content of fuels and therefore SOx emissions are not anticipated to cause a significant problem.
8.8 As no significant effects have been identified, it is not necessary to identify mitigation measures at this stage.
8.9 However, the Scottish Government will explore, with ferry operators, harbour authorities, statutory advisers and others if air quality is an issue at the local level. This will include the consideration of local-level air quality issues as part of the STAG-type appraisals to be undertaken prior to the finalisation of the Draft Ferries Plan.