The Impact of Planted Forests and Windbreaks on Reducing Dust Concentrations in Suburban and Urban Areas

BORIS KRASOVITOV, Andrew Fominykh, Avi Levy, Itzhak Katra, Ben-Gurion University of the Negev, Israel

     Abstract Number: 138
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
Numerous studies reveal that human exposure to fine dust particles in the atmospheric surface layer during dust storms can increase the risk of worsening various bronchopulmonary and allergic diseases. Planting forests and tree belts (windbreaks) reduce airborne dust during dust storms, resulting in a better air quality in urban and suburban areas. This study investigates the effects of planted forests and windbreaks consisting of coniferous trees on the spatial distribution of PM₁₀ concentrations in a region that is frequently prone to dust storms. The present study suggests the numerical model of Particle Deposition on a Forest Canopy (PDFC) supplemented by parameterization of the average collection rate based on the CFD model. 3D numerical modeling of the particulate flow utilizing discrete phase models based on the Eulerian-Lagrangian technique has been carried out. The vegetation element is considered as a prolate ellipsoid approximating in shape to a leaf of Aleppo pine (Pinus halepensis), the dominant tree species in the studied semi-arid zone (Northern Negev, Israel). Model predictions are validated against PM concentration measurements taken during dust storms in a pine forest using real-time dust monitoring devices. Numerical simulations performed using the developed model showed that in high-level dust storms, PM₁₀ concentrations in a suburban environment located 2 km from the leeward side of the pine forest are reduced by 10.5%. Also, numerical analysis was conducted for highly porous windbreaks with widths of 1.25H and 2.5H, where H is the average height of the windbreaks. The calculations showed that windbreaks can decrease PM₁₀ concentrations by 6-8%, even at a considerable distance (about 1 km) from the windbreaks. Modeling indicates that a combination of planted forests and windbreaks near urban areas, as well as vegetation within the city, can help clean and improve the quality of air entering urban areas.