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Reduction of Air Pollution Levels Downwind of a Road with an Upwind Noise Barrier
Citation:
Ahangar, F., D. Heist, S. Perry, AND A. Venkatram. Reduction of Air Pollution Levels Downwind of a Road with an Upwind Noise Barrier. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 155:1-10, (2017). https://doi.org/10.1016/j.atmosenv.2017.02.001
Impact/Purpose:
The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and transport, and support environmental diagnostics/forensics with input from multiple data sources. It also develops media- and receptor-specific models, process models, and decision support tools for use both within and outside of EPA.
Description:
We propose a dispersion model to characterize the impact of an upwind solid noise barrier next to a highway on air pollution concentrations downwind of the road. The model is based on data from wind tunnel experiments conducted by Heist et al. (2009). The model assumes that the upwind barrier has two main effects: 1) it creates a recirculation zone behind the barrier that sweeps the emissions from the highway back towards the wall, and 2) it enhances vertical dispersion and initial mixing. By combining the upwind barrier model with the mixed wake model for a downwind barrier described in Schulte et al. (2014), we are able to model dispersion of emissions from a highway with noise barriers on both sides. The model provides a good description of measurements made in the wind tunnel. The presence of an upwind barrier causes reductions in concentrations relative to those measured downwind of a road with no barriers. The reduction can be as large as that caused by a downwind barrier if the recirculation zone covers the width of the highway. Barriers on both sides of the highway result in larger reductions downwind of the barrier than those caused by a single barrier. As expected, barrier effects become small beyond 10 barrier heights downwind of the highway.
URLs/Downloads:
DOI: Reduction of Air Pollution Levels Downwind of a Road with an Upwind Noise Barrier
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