In the context of the FEDER AIRCITY project, Paris City is modelled with a 3 m resolution with the purpose of computing pollutant concentration relevant for human exposition. This project involves AIRPARIF (Ile-de-France Air Quality Monitoring Network), for emission and immission data, CEA (French Atomic and Alternative Energy Agency) for HPC availability, National Geographic Institute (IGN) for city 3D data. For pollutant dispersion modelling, PMSS software was selected including a parallelised fast 3D wind field and turbulence code and a parallelised stochastic LPDM. A key point in urban air quality is NO
concentration, so the NO/NO
transformation at the street scale is a key issue. In this paper, a preliminary independent study will focus on fundamental questions. After theoretical consideration, a practical case is carried on over the Paris Opera district. The results are compared with standard continuous measurements at two air quality stations of the AIRPARIF monitoring network.
Keywords: SPRAY, Lagrangian particle dispersion model, LPDM, urban pollution, street pollution, NO-NO 2 reaction