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Title of article :
Temporal variations in PM10 and particle size distribution during Asian dust storms in Inner Mongolia
Author/Authors :
Carsten Hoffmann، نويسنده , , Roger Funk، نويسنده , , Michael Sommer، نويسنده , , Yong Li، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
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Abstract :
Two types of increased atmospheric dust concentration could be distinguished in the Xilingele grassland in the Chinese Province of Inner Mongolia, based on the dust origin i.e. local versus supra-regional type. While the local type is characterized by dust emission, dust events of the supra-regional type cause high dust passages and deposition rates. During dust events the temporal variability of the PM10- and PM1-concentrations, the particle size distribution and the friction velocity u* were measured in 5 min intervals using a Laser Dust Monitor (by GRIMM Aerosol GmbH). The threshold friction velocity for local dust emission u*t, at which dust of local soils origin was measured, was above 0.6 m s−1. The total suspended particles (TSP) was collected by MWAC catchers and measured by a Laser Particle Sizer (Analysette 22 by Fritsch GmbH). The average D[4/3] particle diameter of the TSP was 23.0 μm and the greatest particles measured had sizes of up to 100 μm. While fine dust of the PM10 category contained between 58% and 63% of the TSP-mass, coarser particles (>30 μm) contributed to about a fourth of the TSP-mass. At the end of some strong dust storms, the dust concentrations remained at a high level even though wind speeds had already slowed down and u* was below 0.3 m s−1. These phases were characterized by high deposition rates for dust particles greater than 60 μm.
Keywords :
Dust stormDust depositionDust emissionPM10PM1GrasslandInner Mongolia
Journal title :
Atmospheric Environment
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