Mineralogical and Chemical Characterization of Suspended Atmospheric Particles in Ahvaz

Abstract

Particulate matter has dangerous impacts on human health, environment and economy. Recently, dust storms coming from Arab countries have drastically increased, and affect the western and central parts of Iran. The aim of the present study is to investigate the annual and seasonal changes in meteorological parameters associated with the occurrence of dust storms, physical and chemical properties of airborne dust over Ahvaz city during the warm period in 2010. Particle size distribution analyses were conducted by using the laser size analysis techniques. Chemical compositions are measured with different techniques such as X-ray fluorescence, atomic absorption spectrophotometer, and X-ray diffraction. Also, the level of heavy metal contamination in the dust samples was determined using enrichment factor. A disagreement between the occurrences of dust storms, temperature, relative humidity, and rainfall shows the major source of dust storms over Ahvaz city was from the neighboring countries. Scanning electron microscope analyses of dust samples show that airborne dust has rounded irregular, angular and jagged shapes. The sizes of dust particles vary from 0.1 to 55 μm, but PM10 is the dominant particle size. The chemical and mineralogical analysis of dust particles, with major contribution of SiO₂, Al₂O₃, and CaO indicated the likely origin of these particles is the countries neighboring southwest of Iran. Also, the detected trace elements of Br, Mo, S, Zn, Ni, Cr, Co and Hg had non-crustal sources. Generally, airborne dusts in Ahvaz city are geochemically much the same as dust samples in other parts of the world.