CMAQ

The Community Multiscale Air Quality (CMAQ) model is an active open-source development project of the U.S. EPA that consists of a suite of programs for conducting air quality model simulations. CMAQ combines current knowledge in atmospheric science and air quality modeling, multi-processor computing techniques, and an open-source framework to deliver fast, technically sound estimates of ozone, particulates, toxics and acid deposition. 

For further information please visit the EPA website for the CMAQ system: www.epa.gov/cmaq

New features in CMAQ version 5.5 include:

• Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) version 2 including updated formaldehyde chemistry impacting ozone and secondary organic aerosol formation
• New support for running pre-configured global CMAQ simulations coupled with meteorology from the Model for Prediction Across Scales – Atmosphere (MPAS-A)
• Expanded capabilities of the Integrated Source Apportionment Method (ISAM) to quantify source contributions to total secondary organic aerosol (SOA) and individual species
• Updates to ISAM source attribution estimates, mainly impacting coarse particles and secondary organic aerosols formed through cloud processes
• Updates to the Decoupled Direct Method (DDM) to improve second order ozone sensitivities
• Updated chemistry to properly capture photolysis effects from sub-grid clouds
• Revised algorithms for modeling dry deposition (M3DRY and STAGE updates)
• Improved accuracy and error checking for BDSNP soil NO in the MEGAN biogenic emissions algorithm
• MCIP (meteorology pre-preprocessor) updates to grid origin definition for fine scale Lambert Conformal Grids (i.e., < 4km )
• Updates to Sulfur Tracking Model (STM) to properly attribute sulfate from gas phase chemistry
• Updates to the Explicit and Lumped Model Output (ELMO) synthesizer to fix erroneous output for several PM aggregates including PMF_OC, PMF_NCOM, TNO3
• New shp2cmaq python tool to convert GIS shapefiles into gridded netCDF mask files that can be used for defining regions and region families with DESID and using geographic source regions when running CMAQ-ISAM
• Simplified workflows for easier CMAQ installation
• See the full list of CMAQv5.5 updates on our new CMAQ Wiki page. CMAQv5.5 Updates