This paper aims to assess the air quality improvement and resulting health implications in a Portuguese urban area, by testing traffic management scenarios focused on nitrogen dioxide (NO2) emission reduction. To that end, an integrated multiscale modelling system was developed and applied for a typical traffic-activity day using dynamical downscaling to the street level. At this finer scale, the tested scenarios contributed to a reduction of the daily maximum NO2 concentration and health benefits, though the LEZ effect is more felt within its influence area.