CMAQ version 5.3 Release (August 2019)

Announcing the release of CMAQ version 5.3 (August 2019)

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.

What’s new in CMAQv5.3?

  • 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

Download the source code and scripts, and access all documentation for this release from the USEPA GitHub repository,

Two-day and two-week test data for CMAQ version 5.3 are available from the CMAS Data Warehouse,
Full set of 2016 model inputs for the continental US available from the CMAS Data Warehouse,

Please report any bugs or problems with this release to the CMAS User Forum,

Documentation for this release includes the following:

  • Release notes providing details on major changes and new features
  • A new comprehensive User’s Guide, including guidance on what model options are recommended for different types of modeling applications
  • Eight step-by-step tutorials for different features and functions of the software
  • Tables of model species and chemical reactions in each chemical mechanism available in v5.3

CMAQ version 5.3 documentation direct link on GitHub:

Additional user support, including training courses and other CMAS-supported software products is available through the CMAS Center website: