Numerical Investigation of Dry Deposition of Dust Particles on Leaves of Coniferous Plants during Dust Storms

Rahul Tarodiya, BORIS KRASOVITOV, Natan Kleeorin, Avi Levy, Itzhak Katra, Ben-Gurion University of the Negev, Israel

     Abstract Number: 172
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
Dust storms are one of the most significant sources of global atmospheric particulate matter (PM), with serious consequences for human health. During dust storms, daily averages of atmospheric PM concentrations can exceed the WHO's air quality guideline. The present study aims to investigate the effect of forest on PM distribution following dust events in a region prone to dust storms (Northern Negev, Israel). 3D numerical modeling of the particulate flow using a discrete phase model, based on the Eulerian-Lagrangian approach, has been performed to investigate the dust deposition to the vegetation element. The modeling considered several deposition mechanisms namely, the drag force, buoyancy force, the Brownian force, Saffman’s lift force, and thermophoretic force. The vegetation element is assumed to be prolate ellipsoid, approximated to the shape of the Aleppo pine trees in the Lahav forest. The validity of the model prediction is evaluated using field measurement data. Further, the particulate flow field, particle deposition pattern, and deposition efficiency on the vegetation element oriented at different inclination angle to the wind flow is determined. The influences of other essential factors such as particle size and wind velocity on deposition efficiency and the deposition velocity of dust particles to the vegetation element are also analyzed and discussed. The results of this study are substantial for assessing the impact of planting semiarid forests on the level of air pollution in adjacent urban areas during dust events.