Evaluation of pollutant exposure using virtual walkers and large-eddy simulation: Application to an idealised urban neighbourhood

Duan, G. and Takemi, T. and Ngan, Keith (2023) Evaluation of pollutant exposure using virtual walkers and large-eddy simulation: Application to an idealised urban neighbourhood. Science of The Total Environment, 877. ISSN 0048-9697, DOI https://doi.org/10.1016/j.scitotenv.2023.162640.

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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.

Item Type: Article
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]
Uncontrolled Keywords: Pollutant exposure; Virtual walker; Moving receptor; Urban street canyon
Subjects: Q Science > Q Science (General)
T Technology > TD Environmental technology. Sanitary engineering
Divisions: Deputy Vice Chancellor (Research & Innovation) Office > Institute of Ocean and Earth Sciences
Depositing User: Ms Zaharah Ramly
Date Deposited: 16 May 2024 23:45
Last Modified: 16 May 2024 23:45
URI: http://eprints.um.edu.my/id/eprint/38419

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