Geochemical Aspects of Inorganic Aerosols near the Ocean—Atmosphere Interface

The history of air forming various marine fogs off Nova Scotia in August 1975

“…Then, the sea salt concentration of the air can be computed from the salt concentration of the fog water and the liquid water load of th• air. Graphs of these variables (along with papers describing physical and biological data and sampling) for the Nova Scotia fog events August 2-12, 1975, may be found in a compendium which includes the references of Bressan [1977] and Larson [1977]. Radon data for August 1975 are shown in Figure 5, while the results of the chemical analyses of the fog water samples, the pertinent elemental ratios, and the Na/ conductivity ratio normalized to seawater are shown in Table 1.…”

“…The elements and ions in the fog water samples shown in Table 1 are a mixture derived from sea salt, sea foam aerosol, and various components of continental origin [Bressan et al, 1973a]. For these analyses all of the aerosol is expected to be in the condensate phase during rain or fog.…”

“…Air mass tracing information has been supplemented by data from chemical analysis of airborne aerosols and/or fog waters [Houghton, 1955] and from the evaluation of atmospheric gases, including 'freon 11.' Data from chemical analyses for the elements or ions Na, K, Cl-, F- [Wilkniss and Bressan, 1972], and more recently for SO4-- [Bressan, 1977] have been used to characterize an air parcel and to determine if its aerosol composition is dominated by sea surface aerosols, bulk seawater droplets, or continental material. An automatic fog water conductivity device [Bressan, 1976] is the only realtime chemical indicator employed, and chemical analyses are still performed in the laboratory, although techniques with potential for shipboard use are being adopted.…”

“…the gaseous HCI in the condensate phase, and in the absence of the original Na-containing particles a CI-enrichment in the fog or rain would occur[Bressan et al, 1973a].Because many values found in column 7 ofTable Iwere below 90%, SO4 = was determined for the samples. The SO4=/ Na ratio of seawater is 0.25, and allowing for the possibility of SO• = enrichment in sea-surace-derived aerosols (D. J. Bressan, manuscript in preparation, 1979), ratios greater than about 0.40 would indicate some nonmarine source (probably continental/industrial) for the observed persistence of excess sulfate ions, especially in samples 7-15.…”

Organic constituents in eolian dust and surface sediments srom northwest Africa

“…The ultimate composition of oceanic aerosols is due to many source factors in addition to subsequent physical and chemical processes occurring in the atmosphere (see Bressan et al [1973] for a review of factors affecting inorganic aerosol components). Concerning the organic fraction of marine aerosols, investigators [Blanchard, 1964;Barger and Garrett, 1970;Hoffman and Duce, 1974] have shown that the ocean (principally the surface microlayer) can be a source of some of this organic material.…”