Evaluation of pollutant exposure using virtual walkers and large-eddy simulation: Application to an idealised urban neighbourhood
Document Type
Article
Publication Date
6-1-2023
Abstract
Urban air quality studies have primarily focused on pollutant dispersion; however, spatial or temporal concentrations collected at discretely distributed grid points (or fixed receptors) do not reflect the actual pollutant exposure of pedes-trians. Using large-eddy simulation (LES) with virtual walkers implemented, this study investigates pollutant exposure of walking agents (or moving receptors) in an urban turbulent boundary-layer flow developed over an aligned building array under the influence of different wind directions. The spatial variability of the exposure risks are found to be bet-ter captured by the moving receptors than the fixed receptors along the same agent walking tracks. We demonstrate that the actual exposure can differ significantly from results interpreted from data recorded by the fixed receptors (cor-responding to Eulerian estimates) and show that large discrepancies occur in avenues near the source, wherein disper-sion of the point release has not occurred on larger spatiotemporal scales. In most scenarios, optimal evacuation routes are shown to be ones that deviate as much as possible from the dominant wind direction; however, one needs to decide the priority of moving to further avenues first or immediately adjusting the walking direction. The results should serve as a useful baseline reference for environmental health impact assessment and evacuation route planning against haz-ardous releases of air pollutants in more complex urban environments.
Keywords
Pollutant exposure, Virtual walker, Moving receptor, Urban street canyon
Divisions
ocean
Funders
Natural Science Foundation of Liaoning Province of China [2022-KF-18-07],General Research Fund (GRF) from the Research GrantsCouncil (RGC) of Hong Kong [11308021],Environment Research and Technology Development Fund of the Environmental Restoration and Conser-vation Agency (ERCA) of Japan [JPMEERF20192005],Japan Society for the Promotion of Science (JSPS) Scientific Research [21H01591]
Publication Title
Science of The Total Environment
Volume
877
Publisher
Elsevier
Publisher Location
RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS