Chemical relationships in the North Atlantic marine aerosol

A data set from Bermuda of 10 particle size distribution measurements of the marine aerosol, by five-stage cascade impactor and X ray analysis, has been used in a two-component model to resolve tropospheric from sea surface derived trace elements. Assuming a sea surface origin for largest-particle S and Cl and a tropospheric origin for Fe in all particle size ranges, the ratios to Fe of the tropospheric components S, K, and Zn decrease with increasing particle size, but Ca/Fe increases. The net sea surface component for the largest particles exhibits a ratio of Cl/S = 5.7, apparently differing from the seawater ratio of 21.4 because of S enrichment and Cl depletion, relative to the sea surface components of K or Ca which are found approximately in seawater proportions.