Skyllakou, K., Garcia Rivera, P., Dinkelacker, B., Karnezi, E., Kioutsioukis, I., Hernandez, C., Adams, P. J., and Pandis, S. N.: Changes in PM_2.5 concentrations and their sources in the US from 1990 to 2010, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2021-495, in review, 2021