A modelling system for predicting urban air pollution: comparison of modelpredictions with the data of an urban measurement network in Helsinki

We have developed a modelling system for predicting the traffic volumes, em issions from stationary and Vehicular sources, and atmospheric dispersion o f pollution in an urban area. A companion paper addresses model development and its applications. This paper describes a comparison of the predicted N Ox and NO2 concentrations with the results of an urban air quality monitori ng network. We performed a statistical analysis concerning the agreement of the predicted and measured hourly time series of concentrations, at four m onitoring stations in the Helsinki metropolitan area in 1993. The predicted and measured NO2 concentrations agreed well at all the stations considered . The agreement of model predictions and measurements for NOx and NO2 was b etter for the two suburban monitoring stations, compared with the two urban stations, located in downtown Helsinki. (C) 2000 Elsevier Science Ltd. All rights reserved.