Extended Data Figure : Comparison of measurements across 8 participants from the OPS and the APS for which all data are reported in this paper. The OPS measures a larger number concentration because it detects smaller particles, which are generally more abundant than larger particles. Extended Data Table : Measured absolute number concentrations from the series of expiratory activities plotted in Fig. (in cm -3 ). Provided are the statistical parameters visualised by the box plot. Note that these parameters were calculated on the logarithmically transformed data (see Methods). The number of participants for each activity is given by n. Extended Data Table : Lognormal fit parameters for speaking, singing and breathing. For each activity, the size distribution averaged across all participants was fit to a bimodal lognormal fit.