Identification of the origin of atmospheric dust in Isfahan using its chemical and mineralogical properties

Identification of dust sources and its potential to disperse is important, particularly in assessing atmospheric pollution by dust. The atmosphere of Isfahan Province is heavily affected by dust. To study the properties of deposited dust in the Isfahan area, 36 locations distributed over the cities of Isfahan (an urban area with heavy traffic), Khomeinishahr and Falavarjan (an urban area with low traffic) and Zarinshahr and Mobarakeh (an urban and industrial area) were randomly chosen. Dust samples were taken from all the locations for a period of 5 months in 4 periods from August to Mid December 2010. Geochemical and mineralogical characteristics of all the dust samples were examined. The mean EC value of the dust samples was 5.6 dS m-1 showing that it was highly affected by the Na concentration. This variable decreased from Isfahan to Zarinshahr. Dust particles had an average silt, sand and clay content of 52%, 17% and 31%, respectively. In all the 3 areas, kaolinite, palygorskite, chlorite, smectite, illite, quartz, feldspar and plagioclase dominated the clay fraction of dust. These minerals are similar to those reported for the soils of eastern Isfahan. In conclusion, climatic data as well as chemical, physical and mineralogical properties of the dust samples show that, beside the local anthropogenic sources, the soils occurring in eastern Isfahan appear to be the major source of dust in the region.