Measurements of the humidification processes of hydroscopic particles

A number of pure salt aerosols were produced in the laboratory, subjected to a controlled humidity environment. The magnitude of the electrooptic response was measured continuously over a range of relative humidity (RH), which was varied from 20 to 90%, with an integrating electrooptical nephelometer. From such observations the influence of water vapor on the salt aerosols, especially the process of phase transition that occurs at the deliquescent point, can be monitored. The use of electrooptic scattering would appear to be a more sensitive indicator of the effect of water vapor on the aerosols at low RH than conventional light scattering intensity measurements.