Identification of sources and tracking dust storm routes entering from domestic sources to Arak metropolitan using HYSPLIT model

Introduction:
The mega-city of Arak being located in a semi-arid and dry region and proximity to major wind erosion centers especially Meighan desert and wetland is facing the problem of air pollution.The main objective of this study is Identification of Sources and Tracking Dust Storm Routes Entering from Domestic Sources to Arak Metropolitan Using HYSPLIT Model.
Materials and methods:
The present study was carried out using HYSPLIT model, NAAPS model, MODIS satellite imageries and GADS weather data from NECEP weather prediction center for June 22nd, 2016 (Tir 2nd). Modeling was performed using retroviral tracking method for identifying motion direction of dust particles in three stations with a height of 10, 200, and 500 meters, respectively. 
Results and discussion:
The research results demonstrated that most obtained motion directions not only cross Kashan desert and Qom dessert lands and are a source of dust storms but also Meighan dessert wetland and its surrounding dessert lands are the main source of dust particles of the Mega City of Arak. The forward direction of dust particles transporting from Meighan dessert wetland, Kashan dessert and Qom dessert lands in a distance more than 400 km towards north-west of Iran influences  the Air Quality Index (AQI) of cities such as Arak, Shazand, Hamedan and even Sanandaj. 
Conclusion:
These findings are in agreement with the optical depth of dust particles and the amount of surface dust in terms of NAAPS model and the suspended particles concentration in the cities located on the direction of particles dissipation. Also, these results which are in accordance with the previous studies in terms of erosion assessment indicating that the numerical models have the ability for tracking and identifying sources of dust storms satisfactorily.