Community Modeling and Analysis System


CMAQ is an active open-source development project of the U.S. EPA that consists of a suite of programs for conducting air quality model simulations.

CMAQ is supported and distributed by the CMAS Center. CMAQ combines current knowledge in atmospheric science and air quality modeling with multi-processor computing techniques in an open-source framework to deliver fast, technically sound estimates of ozone, particulates, toxics, and acid deposition.

Visit the EPA's CMAQ Site

What's New in Version 5.4

CMAQ Fact Sheet

The U.S. EPA Office of Research and Development and the Community Modeling and Analysis System Center are pleased to announce the release of CMAQ version 5.4.

What's new in CMAQv5.4?

  • Updated chemistry for ozone (O3) and particulate matter (PM) formation from global-to-local scales
  • Introduction of the Community Regional Atmospheric Chemistry Multiphase Model (CRACMM)
  • Biogenic emissions algorithm options have been expanded
  • Revised algorithms for modeling the dry deposition of particles from the atmosphere (M3DRY and STAGE updates)
  • Streamlined building of the coupled WRF-CMAQ system compatible with WRFv4.4+ and an important bugfix for WRF-CMAQ users who previously used the CMAQv5.3 series
  • Improved efficiency, accuracy, and user experience for CMAQ instrumented model extensions CMAQ-DDM-3D and CMAQ-ISAM
  • Expansion of emissions diagnostic output features
  • Introduction of a domain-wide Budget Reporting tool
  • Online integration of common pollutant post-processing tasks (i.e. output total PM2.5 mass and more directly!)
  • Community Contribution: Incorporation of the Two-Dimensional Volatility Bases Set (2D-VBS) chemical mechanism
  • New versions of the Atmospheric Model and Evaluation Tool (AMETv1.5) and the Visual Environment for Rich Data Interpretation (VERDIv2.1.4)

  • See the full list of CMAQv5.4 updates on the EPA's new CMAQ Wiki page: CMAQ Wiki Page.


    CMAQ Review Process

    CMAS, in collaboration with EPA scientists, has organized periodic CMAQ review panel meetings, of 3-day duration each. The review process usually starts by inviting a number of key scientists to participate in the process. The scientists are selected based on their expertise in accordance with the focus of the review session. After reviewing numerous reports and articles and completing their meeting in Research Triangle Park, North Carolina, the review panel prepares a comprehensive report on their findings and recommendations. EPA then responds to the comments of the reviewers. Final review reports are available on the EPA CMAQ website.

    Latest Version: CMAQ version 5.4


    CMAQ In-person Training

    No classes currently scheduled.

    CMAQ Online Training


    Online Resources

    Previous Documentation

    System Requirements

    O/S Linux
    Processor 64-bit x86
    Memory >1 Gb RAM
    Disk Space > 80 Gb
    Software VERDI, I/O API, netCDF,MPI, IDV, Portland Group Fortran, Intel Fortran