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Characteristics and composition of the falling dust in urban environment
AL-Harbi, M.
Abstract
The monthly total amount of dust fall, as well
as its chemical and physical characteristics, was systematically
investigated in Shuwaikh city, Kuwait. Dust samples
were collected on a monthly basis for the entire year of
2009 and analyzed in the laboratory for water-soluble and
water-insoluble matter. Water-insoluble matter represented
the major portion of the total annual dust. ANOVAs
showed significant temporal variation in the concentration
of dust fall over the months (p < 0.05). Higher dust
deposits were encountered between June and August and
ranged from 76.4 to 97.6 ± 2.5 (SD) ton km-2 month-1,
where dusty winds and low humidity are a common attribute
in such arid areas. The main three soluble matter
species measured are nitrate, sulfate, and chloride, and
sulfate was found to be the most abundant inorganic species,
ranging from 0.72 ± 0.13 to 4.1 ± 0.3 ton km-2 -
month-1. Major insoluble matter species measured are ash,
silica, combustible, and tarry. Ash, silica, and combustible
account for 63, 19, and 17.8 % of total insoluble dust, and
58.4, 17.7, and 16.6 % of total dust, respectively. Particle
size distribution was also investigated, and results showed
that dust particles >7 μm were the highest concentration of
falling dust. Metrological conditions were found to play a
vital role in temporal variations in falling dust.
Keywords
Dust fall; Seasonal variation; Water-soluble and water-insoluble matter
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