Community Modeling and Analysis System

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22nd Annual CMAS Conference, October 16-18, 2023

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  • Postdoctoral Researcher, Atmospheric Modeling, Desert Research Institute (DRI)   [APPLY]
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If you need help compiling or running one of our supported products, try the following:

Step 1 Read Model Documentation

Step 2 Search the CMAS Forum

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CRACMM is a chemical mechanism designed to treat all reactive organic carbon emissions to enable the best predictions of ozone, particulate matter, and hazardous air pollutants. Version 1 was distributed in CMAQv5.4 released in October of last year. Since the release, several manuscripts documenting and applying CRACMM to understand the role of different emissions in pollutant endpoints have been published and are now highlighted on the EPA website. In addition, the CMAQ team has set a timeline for releases through 2026 when CRACMM will become the ORD default mechanism. To learn more about CRACMM and the future of chemical mechanisms in CMAQ, see and the updated fact sheet.
important email iconCMAS Users,

After the data breach at the end of 2021, CMAS updated everyone's contact preferences to ensure that no one received any emails from CMAS. As a result, if you want to receive general announcements from CMAS about model releases, upcoming conferences and trainings, and upcoming webinars, you'll need to opt back in. You can do this by following these steps:

* Log in with your email and password
* In the Top Menu, go to User Details > Edit Contact Preferences
* Click the "Add Me" button.

If you see "Remove Me", then you're already set to receive our general announcements.

Information for New Users

Welcome to CMAS! We are a community of environmental and air quality modelers. If you are interested in downloading CMAQ, SMOKE, BenMAP, or any of our other supported models, if you are looking for assistance with any of our supported models, if you are looking for a bibliography of air quality modeling related published works, or you are looking for an atmospheric modeling position, you've come to the right place!

The first thing you should do is create a CMAS user account. This will allow you full access to everything the site has to offer, including model downloads. Once you have a CMAS account, registering for our annual CMAS Conference or model trainings is a snap. Even if you change your email or address, you can easily edit your contact information (once you are logged in). All of your registrations and payment information can be found in your User Details on the top menu.

You can always use our search bar at the top to search within our site. You can always reach a CMAS team member with general CMAS-related questions (please no technical questions) by emailing And don't forget to read the latest issue of the CMAS Newsletter!

Supported Products

BenMAP is a Windows-based computer program that estimates the health benefits from improvements in air quality.

More information

The Community Multiscale Air Quality (CMAQ) Modeling System 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.

Download | Documentation | Training | EPA's CMAQ site

CoST/EMF allows users to estimate the emission reductions and costs associated with future-year control scenarios, and then to generate emission inventories with the control scenarios applied.

Download | Documentation | More Information

C-TOOLS are a suite of web-based modeling and visualization tools for community scale modeling of local air quality.

C-LINE | C-PORT | More Information

The Fertilizer Emission Scenario Tool for CMAQ (FEST-C) system is used to simulate daily fertilizer application information using the Environmental Policy Integrated Climate (EPIC) model for a defined CMAQ domain.

Download | Documentation | More Information

The Input/Output Applications Programming Interface, otherwise known as the I/O API, is the standard data access library for EPA's Models-3 project. The I/O API provides a variety of data structure types for organizing data, and a set of access routines which offer selective direct access to data in terms meaningful to the modeler.

Download | Documentation | More Information

MCIP (Meteorology-Chemistry Interface Processor) is a processing program that takes in meteorological model outputs and prepares meteorological data needed by CMAQ.

Download | Documentation | More Information

The Research LINE-source dispersion model for near-surface releases (R-LINE) research grade dispersion model that is currently under development by EPA ORD for near-roadway assessments. R-LINE is a part of EPA ORD's ongoing evaluation of air quality impacts in the near-road environment. The research model is based upon a steady-state Gaussian formulation and is designed to simulate line type source emissions (e.g. mobile sources along roadways) by numerically integrating point source emissions.

Download | Documentation | More Information

The Sparse Matrix Operator Kernel Emissions (SMOKE) Modeling System allows emissions data processing methods to integrate high-performance-computing (HPC) sparse-matrix algorithms. The SMOKE system is a significant addition to the available resources for decision-making about emissions controls for both urban and regional applications. It provides a mechanism for preparing specialized inputs for air quality modeling research, and it makes air quality forecasting possible.

Download | Documentation | Training |

A collection of tools designed to create spatial surrogates for meteorological and air quality modeling without using GIS software.

Download | Documentation | More Information

VERDI is a Java program for visualizing meteorology, emissions, and air quality modeling data. With options for overlaying GIS Shapefiles and observational data onto model output, VERDI offers a range of options for viewing atmospheric modeling data. VERDI scripting provides a powerful interface for automating the production of graphics for analyzing your data.

Download | Documentation |