A Monte Carlo Model for Soil Particle Resuspension Including Saltation and Turbulent Fluctuations

Abstract

This article describes a stochastic model for resuspension that combines both aerodynamic entrainment and momentum transfer from saltating particles. Two case studies are performed based on soil conditions for the topmost layer of soil in Los Angeles County, CA, and Allegheny County, PA. Wind friction velocity, u * , and soil size distribution were found to be the most important factors in predicting mass and number flux. Under a broad range of wind conditions mass and number fluxes agree to within an order of magnitude with the empirical models of Marticorena and Bergametti (1995) and Ginoux et al. (2001) at u * ≤0.4 m/s. For u * ≤0.60 m s −1 and u * ≥ 0.85 m s −1 aerodynamic forces and splash were the dominant resuspension mechanisms, respectively. Flux was sensitive to wind speed but was not proportional to u * 3 . The mass and number distributions with height peaked at heights corresponding to the maximum concentration of saltating particles and the maximum concentration of suspended particles, respectively. Particles that are most likely to resuspend in the absence of saltation are <10 µm or >100 µm in diameter. The average particle diameter increases with height but is consistently less than the average particle diameter of the parent soil. Simulations reached steady state in approximately 0.01 seconds, and an alternative method of predicting the reduction in near-surface wind speed as a result of saltation is presented as a component of the model.

Survey of the Potential Environmental and Health Impacts in the Immediate Aftermath of the Coal Ash Spill in Kingston, Tennessee

“…Fly ash-airborne particles with diameters less than10 µm (PM10) are regarded as respirable and may affect the human lung and bronchus (40)(41)(42). The process of particulate resuspension will depend on a variety of factors, including the fly ash particulate size and related chemical and physical properties, wind speed and atmospheric turbulence, and likely the relative humidity and surface moisture (43,44). The particles that are of most importance for human health are in the fine particulate (PM 2.5 ) mode, which readily deposit deep in the lung (45).…”

Content and Distribution of Trace Elements and Polycyclic Aromatic Hydrocarbons in Fly Ash from a Coal-Fired CHP Plant

“…Fine-sized fly ash is more persistently available in the atmosphere than coarse fly ash and may cause respiratory illnesses such as asthma, pneumonia and heart diseases (Reynolds et al, 2003;Iordanidis et al, 2008;Harris and Davidson, 2009;Ruhl et al, 2009;Zhang et al, 2012). Particle size distribution of fly ash was measured by a Laser diffraction particle size analyzer.…”

Variability of Natural Dust Erosion from a Coal Pile

“…Various indirect techniques have been used to estimate fugitive particulate emissions-from sources such as bare soils (Gillette et al 1980(Gillette et al , 2004Axtell and Cowherd 1984;Saxton et al 2000;Harris and Davidson 2009), aggregate storage piles (Badr and Harion 2007;Turpin and Harion 2009), or unpaved roads (Cowherd et al 1974)-and relate them to physical processes using empirical methods or mathematical modeling. These emissions can significantly affect air quality near a source and, by their nature, are difficult to quantify.…”

“…Wind erosion of particulate matter from soils and aggregate piles has been studied previously, empirically (Cowherd et al 1974;Saxton et al 2000) or with models (Ono 2006;Laurent et al 2009;Harris and Davidson 2009). Blended methods that used both modeling and observations have also been published (Gillette et al 2004;Turpin and Harion 2009).…”