Dispersion of pollutants and estimation of emissions in a street canyon in Rouen, France

A six-week data set with simultaneous measurements of gaseous pollutants (NOx and CO) and particle matter (PM2.5) inside an urban street canyon and nearby urban background location in Rouen (France) is presented. The experimental results for working days and weekends show the effects on the pollutant dispersion. The background/street concentrations mean ratios are 0.32 for CO, 0.43 for NOx and 0.67 for PM2.5. The OSPM model was used in two ways: (i) to model the pollutant concentrations in the street canyon (direct modeling) and (ii) to predict the traffic emissions from the measured concentrations (inverse simulation). An estimation of the hourly emission factors is obtained for NOx, CO and PM2.5 for working days and Sundays; a daily emission factor is also given. Mean emission factors per vehicle are 0.64 g NOx/km veh, 7.5 g CO/km veh and 0.060 g PM2.5/km veh for the working days.