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Community Multiscale Air Quality Modeling System (CMAQ)

CMAQ Output

CMAQ predicts hourly concentration and deposition values for a large number of chemical species for each location in the modeled domain. These results can be visualized using various tools (e.g. VERDI, Paraview, Vapor, R, Matlab, etc). The data can also be summarized spatially to represent values for a census tract or watershed or it can be extracted for a specific location. Results from some of EPA's modeling efforts are provided for download and visualization. 

Maps of Ozone and PM2.5

What does CMAQ output look like? This interactive map tool can be used to view hourly CMAQ predictions over the U.S. for ozone or PM2.5 for any month in 2012. Model-predicted wind speed and direction are also included to show how the model simulates the movement of air pollution from the pollution sources to downwind locations. This website can be used to explore how ozone and PM2.5 levels change throughout the day, for example morning versus afternoon levels, and throughout different seasons. 

Download CMAQ Data Files

CMAQ input and output files are hosted on the CMAS Data Warehouse, an open-access database for collecting and disseminating meteorology, emissions and air quality model input and output. Each database entry provides metadata for the modeling dataset, instructions on how to obtain the downloadable data, and a unique DOI, allowing for easy citation and discovery of specific datasets. 

Available Model Output Datasets

The following links exit the site Exit

CMAQ Version Data Type Domain Simulation Dates Dataverse DOI
v5.0.2 Hourly and Daily Output for 14 pollutants Continental US Jan 1 - Dec 31 for years 2002-2012 DOIs are year-specific
v5.1 Hourly and Daily Output for 14 pollutants Continental US Jan 1 - Dec 31, 2013
v5.2 Hourly and Daily Output for 14 pollutants Continental US Jan 1 - Dec 31, 2014

Post-processed CMAQ Outputs 

CMAQ output is often combined, or "fused", with observed air quality measurements to remove any consistent model biases prior to using the model predictions for a particular application. Below are examples of bias-corrected CMAQ outputs that are available to download.

Ozone and PM2.5