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 5.3.1

CMAQ Fact Sheet

CMAQ model version 5.3.1 is a minor update to CMAQv5.3 that includes multiple bug fixes to both CMAQ and MCIP (released as MCIP version 5.1), as well as a feature addition to the Detailed Emission Scaling Isolation and Diagnostic (DESID) module to allow for the definition of chemical, region and stream families.
CMAQv5.3.1 Release Notes
FAQ for upgrading to the latest CMAQ version - NEW with v5.3.1 release!

CMAQv5.3 Release

  • A more detailed representation of the characteristics of PM
  • Expanded chemistry for ozone and PM formation from global-to-local scales
  • More complex land and atmosphere interactions to support both air quality and ecosystems applications
  • New emissions interface provides simplified emissions scaling and mapping
  • Increased emphasis on pollutants originating outside the U.S.
  • Enhanced scientific complexity with faster run times
  • Integrated Source Apportionment Method (CMAQ-ISAM) and Sulfur Tracking Method (CMAQ-STM) are fully integrated in the model release
  • Improved computational efficiency and simplified interface of CMAQ-ISAM
  • Code for coupling the WRF meteorology model with CMAQ for online meteorology-chemistry air quality simulations
  • New versions of CMAQ Support Tools including MCIPv5.0, AMETv1.4, VERDIv2.0, FEST-Cv1.4
  • Fully revised documentation to better reflect CMAQ's current structure and capabilities
  • Model-ready inputs for an annual continental US 2016 simulation available to download

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 5.3.1


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