Abstract: Air pollution is a concern worldwide especially in urban areas, in which dispersion is limited and outdoor activies takes place essentially at the street-level and close to traffic emissions. In order to analyze the impact of these emissions on the PM2.5, PM10 e NO2 concentrations inside street canyons, MUNICH model was executed for an urban neighborhood in the Southeast of Brazil. Besides that, analyzes to investigate the sensibility of street-concentrations by changing meteorology, urban geometry, background concentrations and emissions and to verify the impact of distinct mobility urban scenarios were conducted. In order to perfome these analyses, meteorology and background concentrations were obtained from WRF-Urban model v.4.1.5 and CMAQ v. 5.3.2, respectively. Emissions data were determined based on the latest local inventory released by the State Institute of Environment and Water Resources. Particularly, volatile organic emissions were chemically speciated following factors associated with combustion of Brazilian fuels available in the literature. Street network and buildings were defined considering the data from Vitória city’hall website. MUNICH simulations indicated peaks of concentrations associated with low values of planetary boundary layer and/or friction velocity. A decrease by roughly 30% on the aspect ratio in a primary street (street 119, that is near by air quality station used in validation) caused a reduction in about 13% and 9% on average particle and NO2 concentration, respectively, over streets closed to the air quality station. Better agreement between modeled and measured NO2 concentration was achieved when a correction on background concentrations were applied. NO2 concentrations on low traffic roads were most sensible to the change background concentrations. Regarding PM10 and PM2.5, MUNICH simulations suggested a potential overestimation of resuspension emission. Finally, changes on urban mobility could reduced up to 93%, 80% and 66%, respectively, of NO2, PM2.5 and PM10 concentrations at the street-level. However, these scenarios were not strong enough to respect the international recommendations on air quality, and more ambitious restrictions are needed.

Keywords: MUNICH model, particulates, nitrogen dioxide, urban area, traffic emission scenarios.