Characteristics and composition of the falling dust in urban environment

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 month, 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 month. 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 lm were the highest concentration of falling dust. Metrological conditions were found to play a vital role in temporal variations in falling dust.