title: Modelling the dispersion and transport of reactive pollutants in a deep urban street canyon: using large-eddy simulation.
abstract: This study investigates the dispersion and transport of reactive pollutants in a deep urban street canyon with an aspect ratio of 2 under neutral meteorological conditions using large-eddy simulation. The spatial variation of pollutants is significant due to the existence of two unsteady vortices. The deviation of species abundance from chemical equilibrium for the upper vortex is greater than that for the lower vortex. The interplay of dynamics and chemistry is investigated using two metrics: the photostationary state defect, and the inferred ozone production rate. The latter is found to be negative at all locations within the canyon, pointing to a systematic negative offset to ozone production rates inferred by analogous approaches in environments with incomplete mixing of emissions. This study demonstrates an approach to quantify parameters for a simplified two-box model, which could support traffic management and urban planning strategies and personal exposure assessment.
authors.affiliation: School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhong
authors.affiliation: School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. Electronic address: x.cai@bham.ac.uk.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Cai
authors.affiliation: School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: William James
authors.initials: WJ
authors.lastname: Bloss
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D002958:City Planning; D015386:Hazardous Substances; D008956:Models, Chemical; D010126:Ozone; D014186:Transportation
chemical_list: D000393:Air Pollutants; D015386:Hazardous Substances; D010126:Ozone
keywords: Large-eddy simulation; Pollutant removal; Turbulence; Two-box model; Urban street canyon