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Support Center for Regulatory Atmospheric Modeling (SCRAM)

Photochemical Modeling Tools


The Air Quality Modeling Group has developed the Modeled Attainment Test Software (MATS). MATS is a PC-based software tool that can perform the modeled attainment tests for particulate matter (PM2.5) and ozone (O3), and calculate changes in visibility at Class I areas as part of the reasonable progress analysis for regional haze. Detailed information on the recommended attainment tests can be found in EPA's draft modeling guidance, "Modeling Guidance for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze (PDF)."(214 pp, 3.2 M, 2014, About PDF)


  • MATS version 2.6.1: Version 2.6.1 includes an update to the 8-hour ozone attainment test as outlined in the revised guidance document referenced above. Additional changes are documented here: version 2.6.1 change log (TXT).(2 K, 2014) This version performs the ozone, annual average PM2.5, 24-hour PM2.5, and regional haze tests outlined in the modeling guidance.

    There are also updates to the ambient datasets in this installer package (see change log). Additional updates to ambient datasets will be included in future releases and/or posted separately on this page.

    If a previous version of MATS is installed, please uninstall the old version (using Windows "add or remove programs") before installing the new version.
    • MATS 2.6.1 installer package (EXE) - The installer package is large (~208Mb) due to the inclusion of several large example model and ambient datasets.
    • MATS 2.6.1 executable (EXE) - The executable (~7Mb) will only work if the installer package is installed first. We are providing the executable as a separate download because there may be periodic updates to the executable that don't require downloading and installing the entire installer package.
    • MATS 2.6.1 User's Manual (PDF)(371 pp, 5 M, 2014, About PDF) - A PDF version of the user's manual is also included in the MATS installer package. Additionally, the user's manual is built into the help section of the MATS graphical user interface.

SMAT-CE (Beta Version)

The Air Quality Modeling Group has been working over the last several years on a replacement for MATS. The new software is called SMAT-CE (Software for the Modeled Attainment Test - Community Edition) and is being released as a beta version for testing by outside parties. SMAT-CE will fully replace MATS once beta testing is completed and potential comments/bugs are addressed.

SMAT-CE replicates the same tests that are performed by MATS, with identical (or nearly identical) results. SMAT performs the ozone and PM2.5 attainment tests and calculates changes in future year visibility at Class I areas. Detailed information on the recommended attainment tests can be found in EPA's draft modeling guidance, "Modeling Guidance for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze (PDF)."(214 pp, 3.2 M, 2014, About PDF) In addition to replicating the functionality of MATS, SMAT contains numerous improvements:

  • SMAT is much more stable and runs faster than MATS. SMAT should be able to run nationwide PM spatial fields on most common PCs.
  • The SMAT user interface is very similar to MATS, but improved.
  • There is a fairly robust set of GIS mapping tools built into SMAT. There are some quick and easy ways to map both site level and gridded results.
  • The ambient dataset packaged with the SMAT installer package contains updated data. Currently included is complete ozone, PM, and regional haze data for the 2000-2015 period.
  • SMAT-CE is open source and the source code will be available for anyone who is interested.


  • SMAT-CE v1.2 (Beta Version) installer package (EXE) (1.4 G, 2017)

    • Installation instructions

      • Download and open the installer package. The SMAT executable and supporting files will be installed to: C:\Program Files (x86)\SMAT-CE . Once you run the SMAT executable, you will be able to choose between “Annual PM analysis”, “Daily PM Analysis”, “Ozone analysis”, and “Visibility Analysis”.

      • The GUI is new, but will look familiar to MATS users. There is also a user’s guide built into the GUI. Note that all SMAT output files will be sent to a different location from the executable and default ambient data files. All configuration files and SMAT generated outputs are sent to the “My SMAT-CE Files” directory under “my documents”. SMAT uses all of the same data input formats as MATS. All old MATS input files should work directly with SMAT.

SMAT-CE beta test comments and questions should be sent to Brian Timin at by December 15, 2017.