Abstract: Urban air pollution has been a public health issue for many decades. Three-dimensional (3-D) chemistry-transport models (CTM) are used to calculate urban background pollution. However, different types of models are needed to represent the street-scale pollution due to the traffic emission in densely developed area. The Model of Urban Network of Intersecting Canyons and Highways (MUNICH) has been developed to simulate the concentration of pollutants at the street scale. Using accurate traffic emissions is important in MUNICH simulations. The traffic emission significantly affects the concentration of pollutants such as nitrogen oxides (NOx), black carbon (BC) and particulate matter (PM), which are emitted by fuel combustion and mechanical abrasion. In this study, the traffic emission over Paris is estimated taking into account the number of circulating vehicles, the vehicle categories and the fuel types. Multi-scale modeling is performed with Chimere CTM for Greater Paris area and MUNICH for the streets in Paris. Simulations for gas-phase species and PM are conducted during the period from 1 June to 31 July 2022. The simulated NOx, BC and PM concentrations are compared to measurements data at both background and traffic monitoring stations.

Keywords: Urban air pollution, Traffic emission, MUNICH, Chimere, Multi-scale modeling.