CheMPAS-A is a new atmospheric chemistry modeling system that adds chemistry capability to MPAS-A, replacing WRF-Chem and simulating atmospheric chemistry from global to local scales. It integrates the MUSICA library and QUACS, a Python scripting capability that lets researchers add and test new chemistry and aerosol parameterizations without recompiling the model. The project addresses two cyberinfrastructure challenges, stable and portable modeling software, and a sustainable path for new science to be integrated into the model, with applications in public health, agriculture, energy systems, and chemical weather/air quality forecasting.