Hardware For topics related to hardware recommendations, cluster configurations, processor speeds, etc. Infrastructure For topics on how CMAQ is currently organized and distributed on github, maintained on EPA compute servers and shared with the CMAS Community. Land Surface For issues/questions related to land surface modeling algorithms in CMAQ. Benchmark Issues and Errors Share your questions and experience in using CMAQ input and output benchmark datasets, including run-time results, and quality assurance of output data, and impact of libraries and compilers. Chemistry and Aerosols For deep diving into the Chemistry and Aerosol formulations of the CMAQ model. Ancillary Inputs Use this category to report issues with using ancillary inputs (other than Emissions or Meterology) to CMAQ. Meteorology For topics related to CMAQ meteorology. CMAQ-PREP Category to discuss issues related to tools in the CMAQ/PREP directory ICON BCON MCIP Documentation We welcome questions and suggestions on CMAQ documentation. Within the CMAQ GitHub repository (https://github.com/USEPA/CMAQ), this includes the CMAQ User’s Guide, Tutorials, Developer’s Guide and Release Notes found under the DOCS folder as well as sample scripts and README.md files that are provided throughout the code base. Run Time Errors and Issues Having trouble running CMAQ? Review existing topics that have been posted under this category, and if you can’t find something similar, create a new topic and attach your log file and run configuration settings to get help. Post-processing For topics related to CMAQ post-processing tools and software (AMET, Python, R). Compiling For topics related to compiling CMAQ and the libraries that it depends on including MPI, netCDF, I/O API.