An official website of the United States government.

We've made some changes to If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Community Multiscale Air Quality Modeling System (CMAQ)

CMAQ Community Survey Results

In 2016, CMAQ users worldwide participated in a survey circulated by the University of North Carolina's Community Modeling and Analysis System (CMAS) center. The aggregated results allow us to better understand the needs and perspective of the CMAQ community in order to ensure that development is as dynamic and responsive to users as possible. The visualizations below illustrate some interesting  user demographics and the role CMAQ plays for their work.

For complete results and analysis of the CMAQ User's Survey, please download the entire PDF document: 2016 CMAQ User's Survey Results .

The CMAQ team synthesized the results of the survey and created a list of short- and long-term priority action items.  Priorities were determined based on the resources needed to complete the task, the frequency of the user concern or comment in the survey, and the overlap with other internal priorities.  

The following are several specific items that the team was able to make progress on in time for the June 2017 release of CMAQv5.2.

  • Continued utilization of GitHub for sharing latest developments.
  • Increase in speed of model simulations compared to last release.
  • Incorporation of CB6 gas-phase chemistry.
  • New AMET release with easier installation.
  • Improvements to error-checking for common model crashes/warnings/mistakes.
  • Improvements to sample run and build scripts.
  • Improved operational user documentation: New User's Guide for v5.2, improved template for release notes, 5 new step-by-step tutorials.
  • Created content areas on our new website to highlight the diverse CMAQ user community as an important asset to CMAQ development and application.

Our future priorities will include (among others):

  • Development of holistic treatments of gas- and particle-phase chemistry/microphysics.
  • Increased efficiency in numerical techniques offering results with less computational expense.
  • Improved simulation of dynamic interactions with meteorological and land surface models.
  • Expanded tools for visualization of model output and input data.
  • Updated versions of popular analysis tools like the Decoupled Direct Method in Three Dimensions (DDM-3D) and the Integrated Source Apportionment Method (ISAM).

We encourage you to continue to stay involved with future development  of the CMAQ system through participation in CMAS forums and events, future surveys, and through this website.  

User Association with the CMAQ Community

Pie chart showing the length of time cmaq users have been associated with the user community: >1yr - 20%, 1-3yrs - 15%, 3-5yrs - 21%, 5-10yrs - 21%, >10yrs - 28% The CMAQ community continues to grow! Many people have been using the model since it was first released. However, there is a large user group that is new to the model system.

Primary Roles of CMAQ Users

Bar chart showing the various occupational roles of CMAQ, including private industry, air quality research, air quality management, academic research, academia, technical support, and management or administrationThe occupational roles of CMAQ users widely vary. Students, government researchers, and private sector consultants represent some of the groups that use CMAQ.

User Applications of CMAQ

Bar chart showing how respondents reported how they use CMAQ. Emission change scenarios and model evaluation were most popular (67%)The CMAQ model system is used for a variety of applications. Users often take advantage of the model for multiple functions.