This dataset contains the data contributed by EPA/ORD/NERL/CED researchers to the manuscript "Modelling black carbon absorption of solar radiation: combining external and internal mixing assumptions" led by Dr. Gabriele Curci of the University of L’Aquila in L’Aquila, Italy. This dataset is associated with the following publication: Curci, G., U. Alyuz, R. Baro, R. Bianconi, J. Bieser, J. Christensen, A. Colette, A. Farrow, X. Francis, P. Jimenez-Guerrero, U. Im, P. Liu, A. Manders, L. Palacios-Pena, M. Prank, L. Pozzoli, R. Sokhi, E. Solazzo, P. Tuccella, A. Unal, M. Garcia Vivanco, C. Hogrefe, and S. Galmarini. Modelling black carbon absorption of solar radiation: combining external and internal mixing assumptions. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 19(1): 181-204, (2019).