Prior ETEM experiments have observed water uptake and shape changes of nanosized aerosol particles prior to the deliquescence point. However, these techniques are limited to low water partial pressures of ~10 mbar, which is not representative of pressures in the troposphere. Further, prior scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging did not provide significant contrast to distinguish between the droplet and aerosol particle, which prevented visualizing and quantifying aerosol particle dissolution dynamics during deliquescence.