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.