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Compilation of Commercial Marine Vessel Emission Factors and Speciation Profiles


Many of the current marine engine emission factors are based on a limited number of older test data that may not accurately represent the current global or national fleets. This is especially true for vessels that use low sulfur Emission Control Area (ECA) compliant fuels or alternative fuels such as biodiesel, liquified natural gas (LNG), or compressed natural gas (CNG). Particular attention is needed for hazardous air pollutants (HAP) especially persistent organic pollutants (POP) that may have a disproportionate impact on arctic regions. Assessment of POP in the arctic regions will be critical in evaluating the expansion of shipping lanes in those areas.

Though new test data continues to be published, there is no central database that compiles results, assesses their quality and aggregates them in a format that is appropriate for the development of emission factors that can be applied to appropriate activity data for emission inventories.


The first step in this project would be to compile all available marine engine emission and fuel factors and document the associated attributes, such as:

· Vessel type;

· Vessel size (GRT, TEU, passenger, DWT);

· Main/auxiliary engines/ boilers;

· Number of engines tested;

· Date of manufacture of vessel/engines;

· EPA engine Category and Tier level;

· Power rating;

· Engine speed;

· Engine propulsive type;

· Fuel type;

· Fuel consumption rates;

· Application of any controls;

· Operating mode and engine load at the time of testing;

· Methods used for testing; and

· Results from testing.

Once available data has been compiled, a data structure will need to be developed for the database where the factors and profiles will be stored. In developing the data structure, other similar systems should be considered such as ICAO aircraft engine databank and the EPA’s WebFIRE and SPECIATE data systems. Rules for data processing will need to be provided and a scoring system will need to be developed that helps determine the quality and representativeness of the factors and profiles.

Once the database has been populated with the compiled studies, analysis on the data can be performed that weight the factors and profiles based on their quality and number of vessels included in the testing. Variance associated with different data groupings (e.g., vessel type/size, engine speed, controls) can help quantify uncertainty of the data. The date the vessel/ engine was manufactured can also be used to determine the impact engine age has on emission rates. Based on this analysis, it should also be possible to prioritize which factors need to be updated.

Lastly the final database should be made available on the internet, allowing researchers, governmental agencies and NGOs to access it as a tool for the development of national or local marine vessel inventories. The database should be updated regularly to ensure the latest data are included and changes in fuel and technology are represented.


This publicly-available compilation of the most current fuel consumption rates, emission factors and speciation profiles will allow users to fine tune their emission estimates to more accurately represent the fleet they are trying to model and to allow for the development of inventories of comparable quality between researchers and agencies.

Related Research:

There could be a shared interest in this project with the Transportation and Air Quality Committee.


*: *The following activities are not comprehensive, and are intended as a guide to what might be necessary to successfully complete this study:

Phase 1 – Compile available test data, develop data structure and quality ranking criteria

A search should be implemented for all available marine vessel test studies and emission factor programs to fully appreciate available data elements. A data structure will need to be developed that allows for the inclusion of critical and ancillary data elements, facilitates user searches, and can provide summary data.

One of the more challenging tasks for this project will be to develop a scoring method that helps assess the quality of the data included in the database. This will allow the developer to identify data that are missing or need to be updated and will present the user with access to the best quality data that is currently available.

Phase 2 – Compile available emission factors and speciation profiles and score the test data based on the ranking criteria.

Once the data have been compiled into a single database and quality scores assigned to each record, it will be possible to preform meaningful statistical assessments of the data specific to the users’ needs. For example, if a user is interesting in encouraging vessel replacement or the re-engining of older vessels, this database may be of particular importance in determining how emission rates change as the fleet ages.

Phase 3. Database testing

Test the populated database, including:

a) Search functionality;

b) Ability to download search results;

c) Stability on different version of Access;

d) Ease of adding new data to the database; and

e) Possible security issues.

Update database based on comments received from the testers

Phase 4 – Posting the database on the website and update annually.

The posting of the database will need to be made to a secure website. The site should be set up to allow others involved in engine testing to submit their results electronically. Submitted data will need to be vetted prior to inclusion in the next update. Search functions will need to be set up to allow users to easily locate appropriate emission factors. It may be possible to find an academic institute or government agency that could host the site and help with updates.


Governmental agencies such as the EPA, IMO or the UN IPCC, may find that the products of this project compliment their marine vessel programs; to this end their participation would be important in implementing this project in conjunction with academic institutions, consulting services, and non-governmental organizations.


This project has direct value for government agencies, port authorities, academic institutes, consultants, and non-governmental organizations involved in developing marine vessel emission studies.

Sponsoring Committee:AW030, Marine Environment
Research Period:12 - 24 months
Research Priority:High
RNS Developer:Michael Aldridge and Richard Billings
Source Info:EPA CMV emission inventory methodologies, CARB marine vessel methods and data, Swedish Environmental Protection Agency emission factors, as well as academic studies
Date Posted:07/10/2019
Date Modified:08/07/2019
Index Terms:Marine diesel engines, Pollutants, Speciation, Databases, Data analysis, Data collection,
Cosponsoring Committees: 
Marine Transportation
Data and Information Technology

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