Sub-micrometer salt aerosol production: Marine Cloud Brightening

We review in some detail research into experimental spray methods for the production of salt nanoparticles from seawater, which would be needed for the implementation of Marine Cloud Brightening (MCB), a possible climate change mitigation method. We describe first an electrospray method employing Taylor cones spraying seawater, which fortuitously has the right conductivity to produce salt particles in the desired size range (40-100 nm equiv. sphere diameter). A second method involves spraying supercritical salt solutions to get particles in the same size range, as the absence of surface tension yields sprays that are extremely fine. Finally, we describe briefly our ongoing efforts to use effervescent sprays at very high pressure to obtain the desired particle size distribution (PSD).