Detecting origin of dust-fall using ions ratio and morphology of the particles in western Iran

The phenomenon of dust has caused many environmental problems in the western half of Iran. Therefore, recognition of this phenomenon from two aspects of quantity and quality is necessary. This study investigates the ions ratios as well as the morphology of dust particles in order to determine the possible sources involved in dust-fall. Sampling was carried out for one year through the passive method in Sanandaj, Khorramabad and Andimeshk cities.the measured components using Ion Chromatography were evaluated by Cl-/Na+, Mg2+/Na+, and NO3-/SO42- ratios.The resulted data were also analyzed using Exel-2016 and Spss-ver 23 softwares. The results showed that calcium ion has got more percentage average in comparison with other cations in the three stations (3.684%, 5.488%, 4.444%). An-ions have similar average percentages for the three stations. High percentages of ions in dust-fall confirm soil origin and role of evaporites in dust-fall phenomenon. Average of Cl-/Na+ in Sanandaj and Andimeshk stations (0.432, 0.815) were found to be less than seawater standards (1.17). Mg2+/Na+ ratio was higher than the standard of seawater ratio (0.23) for the three stations. Investigation of ratios of the measured ions also showed that dust-fall particles are originated from drylands (transboundary and inland dust production areas) particularly wetlands currently dried because of drought condition and during transportation, by air flows admixtion of ions by different actions are face changes, reactions , and fluctuations. The size of dust were likely to get small by diverging of their shaping origians (transboundary dusts).So the average of dusts size were sanandaj 7.9, Khorramabad 8.9 , and andimeshk 10.6 micrometer. Morphology of the particles was round sphere, semi-sphere , and angular shapes.