Evaluation of the 13 May 2018 frontal dust storm in Shiraz: Stable isotopes signature, source apportionment, and concentration of potentially toxic elements

Frontal dust storms are rare but important weather events in southern Iran affecting visibility and air quality, especially in urban areas. This study investigated the main characteristics of the 13 May 2018 frontal dust storm in Shiraz. The evaluation was based on geostatistical models, and mineralogical, elemental and isotopic data. The mean and median concentrations of major and trace elements followed the order Ca > Al > Fe > Mg > K > Na > Ti > Mn > Zn > V > Cr > Ni > Cu > Pb > Co > Cd, in agreement with the mineralogical composition of dust samples. The spatial distributions of the potentially toxic elements (PTEs) show that the concentrations were higher in the central sectors of city, likely due to the higher population density and traffic volume. Integrated source characterization coupled with positive matrix factorization (PMF) identified that the PTEs sources were geogenic, anthropogenic, and sea salt related. Geochemical isotopic methods, δ¹⁸O and δ¹³C values along with hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) analysis suggest that the dust storm mainly originated from Saudi Arabia. However, local lithological units and resuspended street dust also played an important role in the elemental distributions. These results also indicate that combining various datasets can be beneficial in characterizing the sources of dust storms and their components in southwestern Iran.