Microelement content of surface air above the continent and the ocean

Egorov, V.V.; Zhigalovskaya, T. N.; Malakhov, S.G.

doi:10.1029/jc075i018p03650

Cited by 23 publications

(4 citation statements)

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“…Those elements usually considered of continental origin, Fe, Mn, Si (soil dust) appear with relatively high concentrations during the LRT episode ( Table 2). Also in agreement with our results are clean air aerosol particle concentrations of 4 ng/m3 iron as measured by Egorov et al (1970) a t Novaya Zemlya. Concentrations of lead are found to be 30 times higher during the LRT episode than in the clean Atlantic air.…”

Section: Chemical Composition Of the Aerosolsupporting

confidence: 92%

Deposition and transformation rates of sulphur oxides during atmospheric transport over the Atlantic

Prahm¹,

Torp²,

Stern³

1976

Tellus

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The main subjects of the paper by Prahm et al. (1976) are the long range transport and the deposition of atmospheric sulphur compounds over the North Atlantic ocean. Besides that, the paper discusses some other points of interest, one of which is the size distribution of atmospheric aerosol particles. We will comment on this aspect.The size distribution of atmospheric aerosols is determined in Prahm et al. (1976) by examining particles collected on Satorius 0.8 pm membrane filters with the aid of the Scanning Electron Microscope (SEM). We cannot follow the optimistic view of the authors, that it is possible in this way to obtain a size distribution which can be compared with those of other papers.In general, particles are collected on any filter by several effects. Particles much larger than the pore sue are collected on the filter's surface by the sieving effect. Particles of a sue comparable to the structural elements of the filter (Prahm et al. (1976) show photographs with roughly 1 pm material thickness) are collected by inertia effects (ipaction) on these elements. This occurs mainly on the filter surface or very close behind it, so the particles could travel on nearly straight trajectories. Particles much smaller than the structural elements are collected by diffusion in the depth of the fdter. They will hardly be collected on surface elements, so most of them are not visible for surface inspection. The assumption by Prahm et al. (1976) that only a small fraction of these particles disappears in the depth of the material is certainly not describing the actual deposition.As the photographs (Prahm et al., 1976) show, the inspected surfaces are rather uneven, with holes, structural elements, shadows, obstructed areas, and other effects which prevent complete inspection and counting within the surface area. This is the case with most filters except nuclepore fdters and one has to be very careful in establishing absolute aerosol size distributions from such photographs.Furthermore, one has to keep in mind that Prahm et al. (1976) had to distinguish between 0.2mm and 0.4-mm images on the photographs in order to establish the size distribution of the 0.02-pm to 0.04-pm particles. The uncertainty in determining the size of these particles should then be rather large, even if a hand-held microscope is used afterwards. There are a few more facts to be considered.From our own measurements of the content of marine aerosols the organic material accounts for roughly 10% of the total particle mass (Ketseridis et al., 1976). Most of this material will probably evaporate in the vacuum used for coating the filter surfaces. Recent and unpublished data of our measurements indicate that organic material becomes more abundant with decreasing particle size, so this possible loss of particle material might be quite important for the smallest particles under inspection. As Gravenhorst (1975) showed in his critical study on marine sulphate, this material accounts for roughly 30% of the total mass. Its relative abundance increases as...

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Section: Chemical Composition Of the Aerosolsupporting

confidence: 92%

Deposition and transformation rates of sulphur oxides during atmospheric transport over the Atlantic

Prahm¹,

Torp²,

Stern³

1976

Tellus

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“…Chow et al (1969) In contrast to the above, only a very few studies have been performed on trace elements in less remote locations subject to pollution aerosol influence. Egorov et al (1970) studied 9 trace elements in aerosols of the USSR, at sites ranging from urban to polar. Hoffman et al (1969) The distrib ution of an aerosol particl e populat ion is defined by n(r) = dN/d (log r) where N is the total concent ration of aerosol particl es of radius less than r.…”

Section: Hashimoto and Winchester (1967) Determined Se In Rainmentioning

confidence: 99%

Sources of Trace Elements in Aerosols: An Approach to Clean Air.

Rahn¹

1971

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“…A further factor contributing to higher concentrations in bucket samples may be collection distribution over the winter months. Some data suggest higher concentrations in the winter (Chow and Earl 1970, NAS 1972, Peirson et al 1973) possibly due to meteorological conditions (Egorov et al 1970).…”

Section: Deposition Of Airborne Leadmentioning

confidence: 99%

Deposition of Water and Cations on Artificial Foliar Collectors in Fir Krummholz of New England Mountains

Schlesinger¹,

Reiners²

1974

Ecology

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Atmospheric depositions of water, calcium, magnesium, sodium, potassium, and lead were measured in an Abies balsamea krummholz ecosystem in New Hampshire, U.S.A. Two types of collectors were used. Open buckets captured rainout, washout, and sedimentation (bulk precipitation), while buckets with attached artificial conifer foliage collected intercepted aerosols and cloud droplets as well as bulk precipitation. Water catchment averaged 4.5 times greater in the foliar collectors than in open buckets, and calcium, magnesium, sodium, potassium, and lead deposition averaged 8.3, 6.0, 4.9, 5.7, and 5.5 times greater, respectively, in the foliar collectors. Most of the increase in foliar collectors was due to higher volume catchment but some concentration enrichment through interception was also contributory. These data cannot be extrapolated to elemental deposition per unit area without correcting capture efficiency of collectors to that of natural vegetation. These data do strongly suggest, however, that in areas of high wind and frequent exposure to clouds or fog, such as in montane areas of New England, measurements of total elemental deposition require an evaluation of interception as well as bulk precipitation.

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Microelement content of surface air above the continent and the ocean

Cited by 23 publications

References 0 publications

Deposition and transformation rates of sulphur oxides during atmospheric transport over the Atlantic

Deposition and transformation rates of sulphur oxides during atmospheric transport over the Atlantic

Sources of Trace Elements in Aerosols: An Approach to Clean Air.

Deposition of Water and Cations on Artificial Foliar Collectors in Fir Krummholz of New England Mountains

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