Multi-scale modeling of urban air pollution: development and application of a Street-in-Grid model (v1.0) by coupling MUNICH (v1.0) and Polair3D (v1.8.1)

Abstract

Abstract. A new multi-scale model of urban air pollution is presented. This model combines a chemistry-transport model (CTM) that includes a comprehensive treatment of atmospheric chemistry and transport on spatial scales down to 1 km and a street-network model that describes the atmospheric concentrations of pollutants in an urban street network. The street-network model is the Model of Urban Network of Intersecting Canyons and Highways (MUNICH), which consists of two main components: a street-canyon component and a street-intersection component. MUNICH is coupled to the Polair3D CTM of the Polyphemus air quality modeling platform to constitute the Street-in-Grid (SinG) model. MUNICH is used to simulate the concentrations of the chemical species in the urban canopy, which is located in the lowest layer of Polair3D, and the simulation of pollutant concentrations above rooftops is performed with Polair3D. Interactions between MUNICH and Polair3D occur at roof level and depend on a vertical mass transfer coefficient that is a function of atmospheric turbulence. SinG is used to simulate the concentrations of nitrogen oxides (NO x ) and ozone (O 3 ) in a Paris suburb. Simulated concentrations are compared to NO x concentrations measured at two monitoring stations within a street canyon. SinG shows better performance than MUNICH for nitrogen dioxide (NO 2 ) concentrations. However, both SinG and MUNICH underestimate NO x . For the case study considered, the model performance for NO x concentrations is not sensitive to using a complex chemistry model in MUNICH and the Leighton NO-NO 2 -O 3 set of reactions is sufficient.

Development of a real-time on-road emission (ROE v1.0)model for street-scale air quality modeling based on dynamic traffic big data

“…For evaluating the impact of on-road emissions on air quality at the street level in Guangzhou, an air quality model called the Model of Urban Network of Intersecting Canyons and Highways (MUNICH) was employed in this study with the on-road emission results from the ROE model. MUNICH is a street-network CTM that includes street-canyon and street-intersection 10 components in the model (Kim et al, 2018).…”

“…Thus, as city-scale CFD simulations are very expensive and time consuming, 10 they are currently rare. Recently, some models have been developed and applied to investigate street-level air quality at the city scale (Davies et al, 2007;Righi et al, 2009;Zhang et al, 2016;Kim et al, 2018) by balancing the requirements of high resolution and low computational costs.…”

Nonstationary modeling of NO<sub>2</sub>, NO and NO<sub><i>x</i></sub> in Paris using the Street-in-Grid model: coupling local and regional scales with a two-way dynamic approach

“…Although SIRANE uses a stationary hypothesis for pollutant transport, a new version of SIRANE, named SIRANERISK (Soulhac et al, 2016), removes the steady-state hypothesis and simulates dispersion above street canyons using a Gaussian puff model. The Model of Urban Network of Intersecting Canyons and Highways (MUNICH), developed by Kim et al (2018), presents a similar box-model parameterization as SIRANE, but it does not employ a Gaussian model to determine background concentrations. They may be provided by measurements, as in Kim et al (2018), or regional-scale CTMs, as in our study.…”

CALIOPE-Urban v1.0: coupling R-LINE with a mesoscale air quality modelling system for urban air quality forecasts over Barcelona city (Spain)

“…This approach increases the mesoscale model's ability to resolve urban processes but does not reproduce the specific meteorological conditions in each street as required by dispersion models. Kochanski et al (2015) used a simplified computational fluid dynamics model in combination with WRF to estimate wind conditions at the street level. Hood et al (2018) estimate an urban canopy flow field at the same resolution of the regional model.…”