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Community Multiscale Air Quality Modeling System (CMAQ)
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Access CMAQ Source Code

CMAQ is a suite of Fortran 90 programs that work in concert to estimate ozone, PM, toxic compounds, and deposition throughout the troposphere.  The model requires significant computational resources to run and therefore requires a multi-processor computer running Linux.   CMAQ users should be comfortable with Linux scripting conventions and have some familiarity with the Fortran programming language. Users should also have some familiarity with atmospheric structure, and the physical and chemical processes that occur in the atmosphere.  

The CMAQ source code is currently housed on GitHub. GitHub is a web-based code repository hosting service. It allows for easier code maintenance and distribution. You can download model code from the command line or from your browser.  Users are also encouraged to create an account through the Community Modeling and Analysis System (CMAS) Center to take advantage of the training, conferences and software support provided by the center.   Visit the CMAS Center website to create a user account. 

Command Line Download for CMAQ Base Model from GitHub

CMAQ versions 4.7.1 through 5.4 are available from EPA's CMAQ GitHub Site.  CMAQv5.4 is the current main CMAQ release.  To download the CMAQ source code and scripts from the command line follow the following example template:

git clone -b [MODEL] https://github.com/USEPA/CMAQ.git [MODEL]

To download the latest version of CMAQ [MODEL] should be replaced with main.  All other versions are specified by the version number, e.g., replacing [MODEL] with 5.3.3 will download CMAQv5.3.3.

Note that CMAQ-ISAM is included in the base model beginning with CMAQv5.3, WRF-CMAQ is included in the base model beginning with CMAQv5.3.3, and CMAQ-DDM-3D is included in the base model beginning with CMAQv5.4.  More information on CMAQ-ISAM, CMAQ-DDM, and WRF-CMAQ is provided on the CMAQ Models  page.

Getting Started with CMAQ

  • Check out the "Getting Started" Tutorial for directions on how to prepare your Linux system for installing and running CMAQ.  A complete description of the CMAQ system is provided in the CMAQ User's Guide on GitHub.  Links to available tutorials, the User's Guide and other scientific documentation are provided on the CMAQ Documentation page.  
  • Input and output data for the CMAQv5.4 benchmark can be used to test the build of the base model, WRF-CMAQ, CMAQ-ISAM and CMAQ-DDM-3D.  Directions on how to download the data can be found on the Model Inputs and Test Case Data page. 
  • Technical support and questions about this release should be directed to Help Desk at CMAS. 
  • CMAQ Home
  • Learn About CMAQ
  • Browse CMAQ Applications
  • Download CMAQ
    • Model Source Code
    • Documentation
    • Model Inputs and Test Case Data
    • Resources/Utilities for Model Users
  • CMAQ Research
  • CMAQ Community
  • CMAQ Data
  • About Us
  • Frequent Questions
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on October 14, 2022
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