This collection contains the time series of the aerosol particle number size distribution measured at the ATTO (Amazon Tall Tower Observatory) site from February 2014 to September 2020 at 60 m height. The data in file "SMPS.dat" are used in paper "Occurrence and growth of sub-50 nm aerosol particles in the Amazonian boundary layer" (Franco et al., 2022, ACPD, "https://doi.org/10.5194/acp-22-3469-2022"). When using the data, please also refer to that paper. See "SMPS_ReadMe.txt" for further information.