From my point of view, if your aim is to model salt content in marine aerosols you should split the problem in two steps:
1) To obtain a measure of the salt content at the moment of the aerosol formation. You can assume this salt content is the same as the salinity values on the skin layer measured by satellites (for instance you can download ESA SMOS salinity products here: http://cp34-bec.cmima.csic.es). The salt content will be just a function of the salinity (salt concentration) and the volume of the droplet/aerosol
2) To model any change experienced by the water content of the aerosol (I'm not expert on this by I assume the water content of the aerosol will change depending on the meteorological conditions, temp, humidity, etc...). Obviously this changes will only affect salt concentration on the aerosol but not salt content (unless some precipitation occur, but again I'm not expert on this)
Here you can find salt concentration, load and emissions simulated by the operational WRF-ARW-CHEM of Atmosphere and Climate Dynamics Group of Harokopio University of Athens: http://meteoclima.hua.gr/index.php?option=com_content&view=article&id=162&Itemid=128