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Modeling and Inventories

Mobile Source Observation Database (MSOD)

Ordering Information

The Mobile Source Observation Database (MSOD) is a relational database being developed by the Assessment and Standards Division (ASD) of the U.S. EPA Office of Transportation and Air Quality (formerly the Office of Mobile Sources). Considerable knowledge of vehicle emission testing and of relational database design and query methods is required to make effective use of this database. It is not intended for the casual or novice user. The database has been designed and documented using entity-relationship data modeling methods.

The MSOD contains emission test data from in-use mobile air- pollution sources such as cars, trucks, and engines from trucks and nonroad vehicles. Data in the database was collected from 1982 to the present. While not a purely "random" sample, the data is intended to be representative of in-use vehicle emissions in the United States. Most of the data in the database is from EPA-sponsored test programs.

The database is implemented as a set of approximately 60 tables, supplemented by a larger number of small "translation" or "category" tables which define and explain the legal values for some of its individual data items. All tables are in standard database format (*.DBF) which is usable by a variety of software.

The database includes a User Guide and Reference Manual in PDF format. The Guide provides detailed information on the MSOD design and input data design. The User Guide also provides MSOD's input file structures which allow a user to use EPA's data checking quality control software to review emission data. While ASD is interested in comments and questions regarding the database, it can afford to provide only very limited support beyond this Guide to external users. A copy of the MSOD User Guide and Reference is available on the Modeling & Inventories web page.

While EPA has made considerable effort to assure the validity of the data in this database, the Agency is not responsible for the validity of conclusions reached by others using this data. New records are added continuously to the data sample, though EPA cannot guarantee that all currently available, relevant data is included in the database. Because additions and changes are being made to the database, those using it regularly may wish to request an updated copy every year or so.

Ordering Information

To order a copy of the MSOD database, or if you have questions or comments about the design, linking data fields, input structures, or quality control or quality assurance procedures, please contact Carl Fulper, phone (734) 214-4400 or email: fulper.carlr@epa.gov.

The MSOD User Guide and Reference is available on the Modeling & Inventories web page.

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