We analyze aircraft observations taken in the inflow and upper troposphere outflow regions of ten convective storms to determine aerosol mass scavenging efficiencies. More than 75 % of sulfate and ammonium in all storms and organic aerosols in severe storms are scavenged. Nitrate aerosols have more moderate scavenging efficiencies. Lightning-NOx production and aqueous-phase chemistry can affect outflow concentrations. These results are useful for evaluating chemical transport models.