# CMAQ version 5.3 Release (August 2019)

**URL:** <https://forum.cmascenter.org/t/cmaq-version-5-3-release-august-2019/887>\
**Category:** Announcements\
**Created:** [August 27, 2019, 9:01pm UTC](https://forum.cmascenter.org/t/cmaq-version-5-3-release-august-2019/887 "2019-08-27T21:01:23Z")\
**Posts on this page:** 1\
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**Author:** ![lizadams](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@lizadams](https://forum.cmascenter.org/u/lizadams)\
**Post date:** [August 27, 2019, 9:01pm UTC](https://forum.cmascenter.org/t/cmaq-version-5-3-release-august-2019/887/1 "2019-08-27T21:01:23Z")

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Announcing the release of CMAQ version 5.3 (August 2019)

> **[Community Multiscale Air Quality Modeling System (CMAQ) | US EPA](https://www.epa.gov/cmaq)**
>
> CMAQ is a computational tool used for air quality management. It models air pollutants including ozone, particulate matter and other air toxics to help determine optimum air quality management scenarios.

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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, [https://github.com/USEPA/CMAQ](https://github.com/USEPA/CMAQ)

Two-day and two-week test data for CMAQ version 5.3 are available from the CMAS Data Warehouse, [https://doi.org/10.15139/S3/IQVABD](https://doi.org/10.15139/S3/IQVABD)  
Full set of 2016 model inputs for the continental US available from the CMAS Data Warehouse, [https://doi.org/10.15139/S3/MHNUNE](https://doi.org/10.15139/S3/MHNUNE)

Please report any bugs or problems with this release to the CMAS User Forum, [https://forum.cmascenter.org](https://forum.cmascenter.org)

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: [https://github.com/USEPA/CMAQ/blob/master/DOCS/README.md](https://github.com/USEPA/CMAQ/blob/master/DOCS/README.md)

Additional user support, including training courses and other CMAS-supported software products is available through the CMAS Center website: [www.cmascenter.org](http://www.cmascenter.org)