The dataset contains links to publicly available CMAQ code, CMAQ-ready inputs, model simulation results, and observations for the nitrogen isotopes in nitrate. Please see the work of Kim et al. for more information on this data. This data supports: Kim, H., Walters, W. W., Pye, H. O. T., Foley, K. M., and Hastings, M. G., Isotopic Evidence for Changes in U.S. Energy Fuels and Impact on Particulate Nitrate, Environ. Sci. Technol., https://doi.org/10.1021/acs.est.6c00539, 2026.