Considerable attention has been given to finite‐amplitude waves in aerosols, principally by G. A. Davidson and D. S. Scott [(J. Acoust. Soc. Am.54, 1331 (1973) and J. Aerosol Sci.5, 55 (1974)], who derived and analyzed a single model equation for unidirectional plane waves. This note seeks to correct an error in their analysis for the case in which the thermal and momentum relaxation times of the particular phase are equal. The correct result is that the medium in that case is a relaxing gas of precisely the kind considered by a number of other authors, with equilibrium and frozen sound speeds and a bulk viscosity all capable of simple interpretation. Possibilities not previously recognized are then opened up; specifically that partly dispersed shock waves will occur under appropriate conditions at low frequencies, while at high frequencies the model equation may be reduced to the familiar Varley—Rogers equation, which demonstrates that at a given frequency shock formation may be altogether precluded if the properties of the aerosol are suitably chosen.