Investigation of chemical characteristics and spatiotemporal quantitative changes of dust fall using GIS and RS technologies; a case study, Yazd city, central plateau of Iran

 Background: The phenomenon of dust is a serious environmental problem in dry and semi dry regions. It has a destructive effect for the residents of such regions. Over two-thirds of Iran is in areas of dry and semi-dry climate conditions. Methods: In this research, dust fall measurements were taken in 41 stations across Yazd city using a marble dust collector (MDCO) located in different parts of the city. Next, the chemical characteristics of dust were determined using the XRF method. Finally, levels of dust fall across the 4 seasons of the year and status of the constituent elements of dust were determined through ArcGIS software and the Kriging technique. The Raster calculator function was used to make determinations of the effects of dust fall at each of the stations over the course of the year. Remote sensing system, along with maps taken from Landsat and the band combination technique were processed using ENVI software to extract vegetation density and building density maps of the studied region. Results: Results showed that spring had the highest level of dust fall with a value of 200 g/cm2. In total, in 109 km2 of the studied region had average dust fall of 110 g/m2 that contributed to 12 057 tons of dust over Yazd city in 2015. The constituent elements of the dust fall according to decreasing amounts were as follows: Si>Ca>Al>C>Mg>Fe>K>Na>S>Ti>Cl>P>Mn>Sr>Zn. Conclusion: These results indicate accuracy of the Kriging technique for application in dust zoning. The factors of vegetation and green space were determined as effective on adsorbing dust. Increased building density and height of buildings also contributed to development of dust fall.