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

Due to its location in a semi-arid and dry region and proximity to major wind erosion centres, especially Meighan desert and wetland, the mega-city of Arak is facing the problem of air pollution. The main objective of this study is the identification of sources of and tracking dust storm routes entering Arak metropolitan area from domestic sources using the HYSPLIT Model. The present study was carried out using HYSPLIT model, NAAPS model, MODIS satellite imageries and GADS weather data from the NECEP weather prediction centre for 22 June 2016 (2 Tir 1395). The modelling was performed using a retroviral tracking method for identifying the motion direction of dust particles in three stations with a height of 10, 200, and 500 metres, respectively. The research results demonstrated that most frequent motion directions not only cross the Kashan and Qom desert lands and are, thus, a source of dust storms but also cross Meighan dessert wetland and its surrounding desert lands which are the main source of dust particles of the mega-city of Arak. The forward direction of dust particles transported from Meighan desert wetland and Kashan Qom desert lands over a distance more than 400 km towards the Northwest of Iran influences the air quality index (AQI) of cities such as Arak, Shazand, Hamedan and even Sanandaj. These findings are in agreement with the optical depth of dust particles and the amount of surface dust in terms of the NAAPS model and the suspended particle concentrations in the cities located on the direction of particle dissipation. Also, these results 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.