An Urban Emissions Footprint ModelEPA Grant Number: U915437
Title: An Urban Emissions Footprint Model
Investigators: O'Neill, Susan
Institution: Washington State University
EPA Project Officer: Lee, Sonja
Project Period: August 1, 1998 through August 1, 2001
Project Amount: $90,461
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Civil/Environmental Engineering
The objective of this research project is to develop an urban footprint model to predict the upwind area responsible for a measured downwind pollutant concentration.
The three components that comprise the urban footprint modeling strategy are: (1) mesoscale modeling of the regional wind field; (2) application of a three-dimensional turbulence model simulating the urban landscape; and (3) application of the urban footprint model. The MM5 mesoscale meteorological model developed by Pennsylvania State University and the National Center for Atmospheric Research is a three-dimensional nonhydrostatic model. MM5 provides initial and boundary conditions to the fluids model TEMPEST, developed by Battelle Memorial Institute's Pacific Northwest Laboratory. TEMPEST simulates the complex flows of the urban landscape, such as street canyon flows, the urban heat island effect, and building recirculation zones, by solving the Reynolds averaged Navier-Stokes equations with a k-e turbulence closure formulation. The TEMPEST wind and numerical fields will be used to obtain a numerical solution of the atmospheric diffusion equation. An inverse technique will be applied to the results to infer the distribution of sources from observed downwind concentrations. The field studies, conducted as part of the Urban Metabolism and Trace Gas Respiration Project, will measure trace gas pollutants in real-time—using tunable diode laser technology—and by integrated canister samples analyzed using a gas chromatograph. A Doppler acoustic sounder will be deployed upwind of the urban area to obtain a characteristic wind profile of the winds entering the city. A tethersonde will be used to obtain vertical pollutant profiles at the downwind fringes of the urban area, and tracer gas releases will be conducted to characterize dispersion within the metropolitan area. With these measurements, the urban footprint model can be applied to study pollutant receptor-to-source relationships within an urban area. The results from a field campaign conducted August 21-30, 1998, in Manchester, NH, will be correlated with the model results.