Title of article :
Tracer studies to characterize the effects of roadside noise barriers on near-road pollutant dispersion under varying atmospheric stability conditions
Author/Authors :
Finn، نويسنده , , Dennis and Clawson، نويسنده , , Kirk L. and Carter، نويسنده , , Roger G. and Rich، نويسنده , , Jason D. and Eckman، نويسنده , , Richard M. and Perry، نويسنده , , Steven G. and Isakov، نويسنده , , Vlad and Heist، نويسنده , , David K.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2010
Pages :
11
From page :
204
To page :
214
Abstract :
A roadway toxics dispersion study was conducted at the Idaho National Laboratory (INL) to document the effects on concentrations of roadway emissions behind a roadside sound barrier in various conditions of atmospheric stability. The homogeneous fetch of the INL, controlled emission source, lack of other manmade or natural flow obstructions, and absence of vehicle-generated turbulence reduced the ambiguities in interpretation of the data. Roadway emissions were simulated by the release of an atmospheric tracer (SF6) from two 54 m long line sources, one for an experiment with a 90 m long noise barrier and one for a control experiment without a barrier. Simultaneous near-surface tracer concentration measurements were made with bag samplers on identical sampling grids downwind from the line sources. An array of six 3-d sonic anemometers was employed to measure the barrier-induced turbulence. Key findings of the study are: (1) the areal extent of higher concentrations and the absolute magnitudes of the concentrations both increased as atmospheric stability increased; (2) a concentration deficit developed in the wake zone of the barrier with respect to concentrations at the same relative locations on the control experiment at all atmospheric stabilities; (3) lateral dispersion was significantly greater on the barrier grid than the non-barrier grid; and (4) the barrier tended to trap high concentrations near the “roadway” (i.e. upwind of the barrier) in low wind speed conditions, especially in stable conditions.
Keywords :
Wake zone , Pollutant dispersion near roadways , Concentration deficits , Traffic emissions
Journal title :
Atmospheric Environment
Serial Year :
2010
Journal title :
Atmospheric Environment
Record number :
2235839
Link To Document :
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