This dataset contains the EPA-generated CMAQ model data contributed to support the externally-led analysis in the manuscript "Operational, Diagnostic and Probabilistic Evaluation of AQMEII-4 Regional Scale Ozone Dry deposition. Time to Harmonise Our LULC Masks". This dataset is associated with the following publication: Kioutsioukis, I., C. Hogrefe, P. Makar, U. Alyuz, J. Bash, R. Bellasio, R. Bianconi, T. Butler, O. Clifton, P. Cheung, A. Hodzic, R. Kranenburg, A. Lupascu, K. Momoh, J.L. Perez-Camaño, J. Pleim, Y. Ryu, R. San Jose, D. Schwede, R. Sokhi, and S. Galmarini. Operational, diagnostic, and probabilistic evaluation of AQMEII-4 regional-scale ozone dry deposition: time to harmonize our LULC masks. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 25(20): 12923–12953, (2025).