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 5.3.2

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 5.3.2. CMAQv5.3.2 includes significant updates to the CMAQ Integrated Source Apportionment Method (ISAM) and multiple minor fixes to address issues identified in CMAQv5.3.1. The new CMAQ-ISAM version includes substantial updates to the gas-phase chemistry apportionment algorithms that improves both physical and numerical aspects of the method. Users of ISAM are strongly encouraged to update to CMAQv5.3.2.


CMAQv5.3.2 Updates

  • CMAQv5.3.2 Bugfixes
  • Added ISAM support for bidirectional NH3 flux
  • Revised ISAM method on how gas chemistry affects apportionment
  • Running with Temporally Finer Meteorology
  • Update to the DMS chemistry with CB6r3
  • Update the Lightning NO Vertical Profile
  • Fine aerosol acidity output
  • Add make options to bldmake configuration file
  • Add 2019 data to CMAQ OMI input file
  • Column Modeling
  • Add ERF and SIGN functions to COMBINE

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 5.3.2


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