Impact of building façade geometrical details on pollutant dispersion in street canyons

In urban areas, pollutants are emitted from vehicles then disperse from the ground level to the downstream urban canopy layer (UCL) under the effect of the prevailing wind. For a hypothetical urban area in the form of idealized street canyons, the building-height-to-street-width (aspect) ratio (AR) changes the ground roughness which in turn leads to different turbulent airflow features. Turbulence is considered an important factor for the removal of reactive pollutants by means of dispersion/dilution and chemical reactions. Three values of aspect ratio, covering most flow scenarios of urban street canyons, are employed in this study. The pollutant dispersion and reaction are calculated using large-eddy simulation (LES) with chemical reactions. Turbulence timescale and reaction timescale at every single point of the UCL domain are calculated to examine the pollutant removal. The characteristic mechanism of reactive pollutant dispersion over street canyons will be reported in the conference.

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Effect of traffic tidal flow on pollutant dispersion in various street canyons and corresponding mitigation strategies

Energy and Built Environment ◽

10.1016/j.enbenv.2020.02.002 ◽

2020 ◽

Vol 1 (3) ◽

pp. 242-253 ◽

Cited By ~ 4

Author(s):

Zhengtong Li ◽

Tianhao Shi ◽

Yongjia Wu ◽

Hao Zhang ◽

Yu-Hsuan Juan ◽

...

Keyword(s):

Tidal Flow ◽

Pollutant Dispersion ◽

Mitigation Strategies ◽

Street Canyons

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The effect of exhaust emissions from a group of moving vehicles on pollutant dispersion in the street canyons

Building and Environment ◽

10.1016/j.buildenv.2020.107120 ◽

2020 ◽

Vol 181 ◽

pp. 107120 ◽

Cited By ~ 1

Author(s):

Tianhao Shi ◽

Tingzhen Ming ◽

Yongjia Wu ◽

Chong Peng ◽

Yueping Fang ◽

...

Keyword(s):

Pollutant Dispersion ◽

Exhaust Emissions ◽

Street Canyons ◽

Moving Vehicles

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Wind-tunnel measurements and LES simulations of air pollutant dispersion caused by fire-induced buoyancy plume inside two parallel street canyons

Process Safety and Environmental Protection ◽

10.1016/j.psep.2020.04.047 ◽

2020 ◽

Vol 140 ◽

pp. 151-169

Author(s):

Peng-Yi Cui ◽

Jin-Hao Zhang ◽

Yi-Ping Wu ◽

Yan Zhang ◽

Jia-Zheng Zhou ◽

...

Keyword(s):

Wind Tunnel ◽

Pollutant Dispersion ◽

Air Pollutant ◽

Street Canyons ◽

Air Pollutant Dispersion ◽

Wind Tunnel Measurements

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Pollutant dispersion and thermal effects in urban street canyons

Atmospheric Environment ◽

10.1016/1352-2310(95)00321-5 ◽

1996 ◽

Vol 30 (15) ◽

pp. 2659-2677 ◽

Cited By ~ 349

Author(s):

Jean-François Sini ◽

Sandrine Anquetin ◽

Patrice G. Mestayer

Keyword(s):

Thermal Effects ◽

Pollutant Dispersion ◽

Street Canyons ◽

Urban Street ◽

Urban Street Canyons

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Large eddy simulation of reactive pollutant dispersion : the analysis of physical and chemical interacting processes over idealized urban street canyons

10.5353/th_991022012089703414 ◽

2016 ◽

Author(s):

Tangzheng Du

Keyword(s):

Large Eddy Simulation ◽

Pollutant Dispersion ◽

Street Canyons ◽

Urban Street ◽

Eddy Simulation ◽

Urban Street Canyons ◽

Large Eddy ◽

Reactive Pollutant ◽

Physical And Chemical

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Test of chemistry boundary conditions large-eddy simulations in urban areas

10.5194/egusphere-egu2020-8795 ◽

2020 ◽

Author(s):

Renate Forkel ◽

Basit Khan ◽

Johannes Werhahn ◽

Sabine Banzhaf ◽

Edward C. Chan ◽

...

Keyword(s):

Boundary Conditions ◽

Urban Areas ◽

Turbulent Transport ◽

Pollutant Dispersion ◽

Time Dependent ◽

Street Canyons ◽

Eddy Simulation ◽

Large Eddy ◽

Les Model ◽

Turbulence Generator

Large-Eddy Simulation (LES) allow to simulate pollutant dispersion at a fine-scale turbulence-resolving scale with explicitly resolved turbulent transport around building structures and in street canyons. The microscale urban climate model with atmospheric chemistry PALM-4U (i.e. PALM for Urban applications; Maronga et al., 2019, Met. Z., https://doi.org/10.1127/metz/2019/0909) has been developed within the collaborative project MOSAIK (Model-based city planning and application in climate change). With such a large-eddy simulation (LES) model, pollutant dispersion around buildings and within street canyons can be simulated, with explicitly resolving the turbulent transport in urban environments.Cyclic boundaries are frequently applied in LES in order to obtain lateral boundary conditions for the turbulent quantities. In addition to the default cyclic boundary conditions, PALM-4U allows also time-dependent boundary conditions from regional models to account for variable weather conditions and regional scale pollutant transport. Turbulent fluctuations, which are not included in the boundary conditions from the regional simulation but are needed as additional boundary conditions for the LES model are produced by a turbulence generator (Maronga et al, 2019, GMDD, https://doi.org/10.5194/gmd-2019-103).PALM-4U simulations with and without time dependent boundary conditions from regional simulations with WRF-Chem are performed for different setups in order to test the impact of the domain configuration. The simulations indicate that cyclic boundary conditions can lead to unrealistic accumulation of pollutants over urban areas with strong sources, which is not the case when time-dependent boundary conditions are applied. However, even though a turbulence generator is applied, explicit setting of time-dependent boundary conditions requires large model domains, in order to obtain fully developed turbulence within the domain of interest, increasing the computational demand of the simulation.

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