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 5.3.3

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 5.3.3. CMAQv5.3.3 is a minor update to CMAQv5.3.2 that includes multiple bug fixes. These updates include restoration of windowing capability, allowing users to provide gridded input files which were larger in horizontal extent than the simulated domain. This release also includes a new version of the WRF-CMAQ coupled system with a streamlined build process. Users of WRF-CMAQ are strongly encouraged to try the latest version. Additionally, MCIP users should note that starting with this release we are aligning the version numbering between CMAQ and MCIP, i.e., the MCIP updates included in this release are labeled MCIPv5.3.3.


CMAQv5.3.3 Updates

  • CMAQv5.3.3 Bugfixes
  • Domain windowing option restored
  • DMS chemistry bug fix
  • HONO Deposition Fix for the STAGE Deposition Option
  • HONO Deposition Fix for the M3DRY Deposition Option
  • Correction to BEIS in-line emissions for RACM2
  • Bugfix, clean-up, and added option in bldscript for distr_env.c
  • POST tool bug fixes in hr2day and sitecmp_dailyo3
  • Updated bldmake & config_cmaq.csh to add mpi library in CCTM Makefile
  • Provide appropriate error message and abort if OMI photolysis file is missing
  • Revise how the photolysis module checks write time for diagnostics.
  • Remove Differences in Predictions between PHOTDIAG True and False.
  • Correct O3 deposition to wet soil in the STAGE deposition option
  • Correct Mosaic Land Use Specific Dry Deposition Velocity Diagnostic Output
  • Resolve error in Process Analysis reintialization after aerosol processing
  • KZMIN setting update

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 5.3.3


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