Marine Air Pollution and Global Climate Change
Masaru HIRATA *
Right now there is no international restriction or regulation for the exhaust gas emission from international marine transport. SOx and NOx emission from international marine transport except domestic marine transport in each country are estimated as around 4% and 7% of the total amount of the emission in the world respectively. Also, after COP3 in Kyoto, CO2 emission from ships should be taken into account for the pollution. The total amount of CO2 emission from ships is estimated as around 2% of the total emission in the world.
In these ten years, the International Maritime Organization (IMO) has been active to reduce exhaust gas emission from ships. As a member country of IMO, Japan has a responsibility to contribute to these international activities through some fundamental researches including experimental measurements. This paper introduces some recent activities in Japan, to reduce the environmental pollution caused by the exhaust gas emission from ships.
Keywords: Environmental Pollution, Marine Diesel Engine, SOx, NOx, CO2 Emission from Ships
International Maritime Organization (IMO) has been active to reduce exhaust gas emission from international marine transport after 26th MEPC (Marine Environmental Pollution Committee) in 1988. At that meeting, Norway initially proposed to discuss this matter in this committee. At 29th MEPC in 1990, Norway presented data concerning SOx and NOx emission from international marine transport except domestic marine transport as 4% and 7% of the total emission from all over the world respectively. In Europe, SOx emissions from ships may influence surrounding land is areas such as the Strait of Dover, English Channel, and/or Scandinavian Peninsula where marine traffic is heavy. In such areas, the movement of controlling SOx emissions from ships can be seen in parallel with the plan of exhaust gas on the ground. IMO agreed to study a local control system which limits sea areas where SOx is controlled.
After 9 years discussions in MEPC, in September 1997, the Conference of Parties to the International Convention for the Prevention of Pollution from Ships, as modified by the Protocol of 1978 relating thereto (MARPOL 73/78), adopted a new Annex VI entitled "Regulations for the Prevention of Air Pollution" from Ships".
In this Annex VI , concerning the issues of SOx, a concept of global capping of sulphur content within fuel oil has been adopted. The sulphur content of any fuel oil used on board ships shall not exceed 4.5% by mass. Monitoring the worldwide average sulphur content of residual fuel oils supplied for use on board ships has been going on, and the data gathered by testing companies have shown that the current average figures for the sulphur content are in the order of 3% by mass and the maximum is up to 4.5%. As an example of SOx Emission Control Area, the Baltic Sea area is designated. The sulphur content of fuel oil used on board ships in a SOx Emission Control Area does not exceed 1.5% by mass.
Concerning the issues of NOx, a new Technical Code on Control of Emission of NOx from Marine Diesel Engines was adopted. The Annex requires that the survey of engines and equipment shall be conducted in accordance with this Code. When this 1997 Protocol enters into force, the requirements of the NOx emission restriction shall apply to each diesel engine retroactively with a power output of more than 130 kW which is installed on a ship constructed on or after 1 January 2000, or which undergoes a major conversion on or after 1 January 2000.
In order to contribute to these international activities, the Marine Engineering Society in Japan (MESJ) organized a committee in 1992, named Anti-Marine Air Pollution Committee (hereinafter referred to as "MAP Committee"), with the financial support of the Environmental Agency of the Government of Japan. This committee has been still going on and making an assessment for the effect of air pollution from ships and also making a general survey of the technological methods to reduce the pollutants including particulates. Also the Ministry of Transport of the Government of Japan organized a committee within Ship & Ocean Foundation (referred to as "S&O Committee") from 1990 to '94, to investigate the NOx reduction and measurement technologies including standards. They also organized another committee in the Association for Structural Improvement of the Shipbuilding Industry (referred to as "Kibankyo Committee") from '91 to '97, to develop NOx reduction equipment on board.
For the greenhouse gases, UNFCCC (United Nations Framework Convention on Climate Change) has requested IMO, following to the Kyoto Protocol, to discuss options to reduce greenhouse gases emitted from ocean carriers. The Ministry of Transport of Japan has organized a committee in the Ship & Ocean Foundation in 1998 to estimate CO2 emission from ships based on their fuel oil consumption.
The author has been working as the chairman of these committees , and this paper summarizes the principal results of the investigations performed by these committees.
*Shibaura Institute of Technology
Fukasaku 307, Ohmiya, Saitama, 330-8570 JAPAN
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