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Evaluation of US and UK Models in Simulating the Impact of Barriers on Near-Road Air Quality
Heist, D., C. Hood, A. Venkatram, S. Perry, V. Isakov, M. Snyder, L. Brouwer, D. Carruthers, J. Stocker, AND S. Smith. Evaluation of US and UK Models in Simulating the Impact of Barriers on Near-Road Air Quality. ISES 2015 Annual Meeting, Henderson, NV, October 18 - 22, 2015.
The National Exposure Research Laboratory (NERL) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA mission to protect human health and the environment. AMAD research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
The possibility that roadside noise barriers can act to mitigate traffic-related air pollution exposures for people living and working near major roadways is being considered in the context of public health protection. Air pollution dispersion models that can accurately simulate these effects are needed to fully assess these impacts for a variety of applications. To assess the ability of two dispersion models capable of accounting for the barrier effect, three different studies of near-road noise barrier dispersion have been used for model evaluation and intercomparison purposes. This paper presents comparisons, using the three datasets, of the performance of barrier algorithms in two different dispersion models: US EPA’s R-LINE (a research dispersion modelling tool under development by the US EPA’s Office of Research and Development) and CERC’s ADMS model (ADMS-Urban).The first study was performed in the meteorological wind tunnel at the US EPA and simulated line sources near noise barriers of different heights to investigate that aspect of barrier design in a well-controlled environment. The second was an idealized tracer field study was performed in Idaho Falls, ID, USA with a 6-m high noise barrier and a finite line source. This study employed 58 samplers arrayed predominantly downwind of the source and has the advantage of being conducted in a variety of atmospheric conditions but with a controlled source of pollutants. The third is a field study performed along a major thoroughfare in Phoenix, AZ designed to investigate the effect of a roadside barrier on traffic-generated pollutant dispersion under real driving conditions. Measurements of various pollutants were made downwind of roadway sections with and without a noise barrier. In all three studies, velocity and concentration measurements were used to characterize the effect of the barrier on dispersion.