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A field and modeling study to assess the potential mitigation of near-road pollution by vegetative and structural barriers
Citation:
HAGLER, G., M. Lin, A. Khlystove, W. Tang, M. J. Freeman, V. ISAKOV, J. FAIRCLOTH, D. HEIST, S. G. PERRY, A. F. VETTE, Z. DRAKE, AND R. W. BALDAUF. A field and modeling study to assess the potential mitigation of near-road pollution by vegetative and structural barriers. In Proceedings, 103rd Annual Conference of the Air & Waste Management Association, Calgary, AB, CANADA, June 22 - 25, 2010. Air & Waste Management Association, Pittsburgh, PA, Paper #861, (2010).
Impact/Purpose:
conference paper
Description:
Recent modeling and field studies have demonstrated that roadside structures such as noise barriers or tree stands, may significantly affect the local-scale transport of on-road emissions to areas located adjacent to major roadways. When directly downwind of a major roadway, concentrations of air pollutants associated with fresh traffic emissions (carbon monoxide and ultrafine particles) were lower in areas located behind a noise barrier relative to simultaneous measurements in an open field. A wind tunnel experiment also confirmed decreases in ground-level concentrations with the presence of a roadside barrier relative to a flat terrain case. However, for more complex geometries, such as the addition of trees to a street canyon, modeling results predict that the barrier location may cause either improved or degraded air quality along roadside pedestrian walkways. In order to better understand the effects of barriers on near-road air quality, U.S. EPA Office of Research and Development is conducting a multi-faceted research study bridging from field measurements to modeling. Mobile monitoring field measurements were conducted at three roadside locations in North Carolina - two sites with vegetative barriers and one with a brick sound wall. In addition, wind tunnel experiments were conducted to observe the penetration efficiency of fine and coarse particles through evergreen vegetation. Finally, a computational fluid dynamics model of a roadway was developed, simulating a six-lane highway and a single-lane access road parallel to the highway, which are separated by a solid or porous barrier.
URLs/Downloads:
NRMRL RTP P 1066.PDF (PDF, NA pp, 161 KB, about PDF)CONFERENCE INFORMATION
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