Introduction
Included in the Supporting Information are a description of the instrumentation and measurement methods used in the paper (Text S1), and a figure (Figure S1) showing aerosol size distributions for six flights with repeated passes through smoke plumes at different distances from the smoke source. Also included in that figure are total aerosol number concentrations and geometric mean aerosol diameters as a function of calculated plume age. Plume age was calculated from the distance to the fire center and average wind speed as in Garofalo et al. (2019).