The Effect of Urban Configuration and Bi-molecular Reaction on Air Pollutants Concentration in Urban Street Canyons

Abstract

Large-eddy simulations (LES) are performed on the reactive air pollutants dispersion in three kinds of urban street canyons that have various roof-heights levels. A line source that emits nitrogen monoxide (NO) is set on the bottom of the canyon space in each case. NO disperses on the cavity eddy and reacts with Ozone included in the free stream. The reaction has a significant influence on the concentration field of a city block scale. However its influence rate changes in different urban configurations, making magnitude relations between concentrations of Ozone, NO and the product are altered in three analysis cases.