Trace metal concentration as a function of particle size in marine aerosols from Bermuda

Abstract

Three samples of marine aerosols were collected from a 20 m high tower on the coast of Bermuda using a high volume cascade impactor. The elements Na, Al, Fe, Mn, Sc, Th, and Co were found primarily on particles with aerodynamic equivalent radii of approximately 1 µm or greater and their source is likely either the sea (Na) or crustal weathering. However, the elements Cu, Zn, As, Cd, Pb, Sb, Se, and Hg are present in concentrations too high to be explained by a bulk seawater or normal crustal weathering source. The major mass of these elements is present on particles with equivalent radii less than 1 µm;, suggesting that a volatile phase is critical at some stage of the atmospheric lifetime of these anomalously enriched elements in mid‐ocean marine aerosols.

African and Asian Dust: From Desert Soils to Coral Reefs

“…African and Asian dust consists primarily of clay soil minerals such as illite, quartz, kaolinite, chlorite, microcline, plagioclase, and calcite (Prospero 1981), which may undergo chemical change during aerosol transport (Ravishankara 1997). Some elements (e.g., manganese, iron, scandium, cobalt) occur on African dust particles in concentrations similar to average crustal abundance, whereas other elements (e.g., mercury, selenium, lead) accumulate, via scavenging, at concentrations three orders of magnitude greater than mean crustal abundance (Duce et al 1976). In the late 1990s, the Atmosphere-Ocean Chemistry Experiment investigated the chemical composition of Atlantic aerosols (Arimoto et al 1995).…”

“…The chemical composition of aerosols is a product of the origin and history of the dust (e.g., Duce et al 1976, Arimoto et al 1995, Perry et al 1997. African and Asian dust consists primarily of clay soil minerals such as illite, quartz, kaolinite, chlorite, microcline, plagioclase, and calcite (Prospero 1981), which may undergo chemical change during aerosol transport (Ravishankara 1997).…”

Contribution of Saharan dust to the Central Mediterranean Basin

“…Very few data on the wet/dry deposition ratio of trace metals over the Mediterranean are available (Gueiu et al, 1991;Guerzoni et al, 1991). We therefore integrated those data into the model proposed by Duce et al (1976), in which it was assumed that wet deposition is approximately three times that of dry deposition, so that the total metal flux is four times the dry deposition flux.…”

Tropospheric arsenic over marine and continental regions

“…The mass median diameter (MMD) of arsenic in urban aerosols is about 1 #m [Rahn, 1976;Paciga and Jerois, 1976]. A MMD of about 0.8 #m has been measured for arsenic in a Bermuda marine aerosol sample [Duce et al, 1976b]. Mass size functions of arsenic in urban aerosols indicate that there are both large and small particle anthropogenic sources [Paciga and Jerois, 1976].…”