Abstract
Maritime air was followed from the coast, and measurements of seal-salt nucleus distributions were carried out. It was found that the concentrations encountered in air which had been over land for a considerable time ranged from very low values to values approaching those usually found in maritime air. It also seemed that convective cloud formation or precipitation rapidly lowered the salt concentration. In the absence of such factors, no appreciable diminution in total concentration occurred; vertical mixing, however, often gave rise to elevated salt concentrations at higher levels. Very low concentrations were found above post-frontal subsidence inversions over land, in air streams which had recently come from over the ocean.
