The invention is directed to an improved electrohydrodynamic (EHD) apparatus having a time varying voltage component. The invention further relates to the use of such enhanced EHD apparatus to produce respirable and non-respirable aerosols from highly aqueous liquids, as well as the use of such aerosols. The combination of modifying surface rheology and superimposing a time varying waveform onto the direct current (DC) electrical field enables electrohydrodynamic aerosolization of high aqueous content formulations (>50% water) beyond what can be achieved through other means, including the individual gains by applying surface rheology modification and superimposing a sinusoidal waveform onto the DC electrical field individually.
