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Last Updated: Tuesday, September 10, 2013 3:37 PM
CT-EMFAC 4.1 is based on EMFAC 2007, which has been replaced by EMFAC 2011. CT-EMFAC 5 is based on EMFAC 2011, but is not yet approved by U.S. EPA for conformity use.
New environmental studies started since September 30, 2011 should be using EMFAC 2011. Conformity studies started before September 6, 2013 may use EMFAC 2007, but conformity studies started after that must use EMFAC 2011.
CT-EMFAC is an interpretation of the California Air Resource Board's EMFAC model (more EMFAC information) that simplifies the process of developing composite emission factors for highway project air quality analysis. It also extends EMFAC to include EPA's 2007 priority mobile source air toxics (with use of an Excel spreadsheet for some of them in EMFAC 4.1), which require off-model speciation of Total Organic Gases (TOG) when the standard EMFAC model is used.
CT-EMFAC was developed in consultation with ARB staff, and and is designed to be used in place of the full EMFACmodel when the detailed fleet and other planning assumptions used by EMFAC are not available or not needed. Typical use would be to develop composite emission factors for running CALINE4 using Appendix B procedures from the CO Protocol, or for basic emission analysis of a highway project.
Two CT-EMFAC versions are currently available:
- CT-EMFAC 4.1 is based on EMFAC 2007. It is retained for historical purposes and to support completion of projects that were begun using EMFAC 2007 before EMFAC 2011 was made available for conformity use. CT-EMFAC 4.1 and EMFAC 2007 may only be used for conformity analysis that started before September 6, 2013. The CT-EMFAC 4.1 package includes a spreadsheet for generating naphthalene and POM emission estimates.
- CT-EMFAC 5 is based on EMFAC 2011. It should be used for environmental analysis purposes, but cannot be used for conformity analysis purposes until it is approved by U.S. EPA Region 9 following the process defined in the March 2013 EMFAC 2011 availability notice. Until EPA approves CT-EMFAC 5, project-level conformity analysis should use EMFAC 2011 as distributed by the California ARB, especially the EMFAC 2011-PL component. CT-EMFAC 5 includes napthalene and POM analysis as part of the main user interface, and does not require a separate spreadsheet as was used with CT-EMFAC 4.1.
A "Databridge" tool is also available to help format link-based travel data for use with the batch mode of CT-EMFAC. This tool is a "beta" product and could contain errors or inconsistencies - if you discover problems please let us know.
CT-EMFAC requires .NET 2 or higher runtime support. and Windows XP or later. Multiple versions of the .NET runtime can be used side-by-side on one computer.
CT-EMFAC also depends on the Microsoft Data Access Components (MDAC) 2.8 or later. Windows 7 and later provides MDAC or equivalent data access components as part of the operating system. If they are missing in an earlier Windows version, MDAC (32-bit/x86 only, Windows XP) can be downloaded from Microsoft .
Administrator access to the computer is required to install or upgrade .NET and, if missing, the data access components. CT-EMFAC itself does not require administrative rights to install or use, because it should not be placed in the "Program Files" folder or some other restricted-access location. Create a new folder where the user has full (read/write) access, then extract all the files in the CT-EMFAC ZIP archive to it maintaining the file and folder structure and names in the zip file.
CT-EMFAC requires 400-600 MB of disk space after installation, plus space used for project files.
- Full Package, Version 4.1 (110 MB ZIP archive file; CT-EMFAC.exe dated 7/28/2011)
(includes spreadsheet template supporting napthalene & POM analysis)
- Readme file, Version 4.1 (Text; included in the full package)
- User Guide (PDF; included in the full package zip file)
- Technical Memo - Naphthalene & POM Modeling Guidance (PDF; included in the full package)
- Full Package, Version 5 (170 MB ZIP archive file; CT-EMFAC.exe dated 9/10/2013)
- Readme file, Version 5 (Text; included in the full package)
- Technical Memo - Relationship of CT-EMFAC and EMFAC 2011-PL (PDF; included in the full package)
- Databridge tool (beta product) - consult the help file included in the zip file for usage instructions