(NAS Colloquium) Geology, Mineralogy, and Human Welfare (1999) / Chapter Skim
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Long-range Transport of Mineral Dust in the Global Atmosphere: Impact of African Dust on the Environment of the Southeastern United States
Long-range Transport of Mineral Dust in the Global Atmosphere: Impact of African Dust on the Environment of the Southeastern United States
Pages 3396-3403
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From page 3396... ...
This paper describes some features of the large-scale distribution of dust and identifies some of the geological characteristics of important source areas. The transport of dust from North Africa is presented as an example of possible long-range dust effects, and the impact of African dust on environmental processes in the western North Atlantic and the southeastern United States is assessed.
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From page 3397... ...
The Global Scale Distribution of Mineral Dust Studies performed over ' the past few decades have clearly established that large amounts of soil dust are mobilized by winds, mostly in arid regions, and that substantial quantities can be carried great distances (reviewed in refs.
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From page 3398... ...
2 is that some regions stand out as persistent dust sources. Although many source regions are obscured by dense dust plumes (for example, in West Africa, where high concentrations of dust are present almost continuously)
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From page 3399... ...
Although many sources can be identified in TOMS, there are large regions where the sources are obscured by persistent dust clouds during much of the year in West Africa and the Arabian Peninsula, for example. In some cases, TOMS shows active sources that cannot be readily associated with topographical lows nor with readily identifiable sources of runoff.
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From page 3400... ...
2~. Dust episodes usually extend over several days or more; given the persistence of the trade-wind flow, this suggests that the scale of the dust events is on the order of several hundred to 1,000 km; this scale is consistent with satellite depictions of aerosol distributions over the western North Atlantic and the Caribbean (Figs.
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From page 3401... ...
In the discussion of dust properties in North Africa, it was noted that there was a clearly identifiable mode in the mass distribution in the size range below 10 ,um. Measurements over the western North Atlantic show that the dominant size in the mass distribution is in the range of several micrometers and that there is very little mass above ~10 ,um; thus, the larger particles have been deposited during transit.
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From page 3402... ...
Finally, there is a renewed interest in the health effects of fine particles as reflected in the new EPA regulations regarding suspended particles <2.5 ,um in diameter. In many regions of the world, mineral dust is the dominant aerosol constituent, and, consequently, dust could constitute a widespread health threat.
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From page 3403... ...
(1989) in Paleoclimatology and Paleometeorology: Modern and Past Patterns of Global Atmospheric Transport, eds.
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