Comparison of predicted and observed PM 10 concentrations in several urban street canyons Tolga Elbir & Melik Kara & Abdurrahman Bayram & Hasan Altiok & Yetkin Dumanoglu Received: 14 April 2010 / Accepted: 25 June 2010 / Published online: 17 July 2010 # Springer Science+Business Media B.V. 2010 Abstract This paper presents an evaluation of a street canyon model (Operational Street Pollution Model) in several urban streets having different configurations. The model was performed for the prediction of particulate matter (PM 10 ) concentrations from exhaust emissions of mobile sources in five street canyons in the city of Izmir, Turkey. Hourly concentrations of PM 10 were observed at the streets and the relevant hourly meteorological parameters were measured at the roof level. The hourly street level measurements by a mobile ambient air quality monitoring station and on-site automatic traffic counts were conducted for 1 week in each street during the period of November 2007 and March 2008. The urban background concentrations were also obtained from four stationary air quality monitor- ing stations in the city during the measurement campaigns and they were included in the modeling studies as the contribution of background air quality. Finally, statistical analyses were carried out to evaluate the model performance by comparing the predicted and observed time series of PM 10 concentrations using a correlation coefficient and an index of agreement (IA). The IA varied from 0.87 to 0.98 at the symmetric canyons and the correlation coefficient ranged from 0.68 to 0.92, indicating modeling performances ranging from acceptable to very good. The similar values were calculated between 0.74 and 0.76 for IA and between 0.34 and 0.41 for correlation coefficient at the asymmetric canyons. The best agreement between predicted and ob- served PM 10 concentrations (IA=0.98, R 2 =0.92) was found for Cumhuriyet Avenue in this study. These values are found as the best agreement in overall studies in literature. Keywords OSPM . Street canyon . PM 10 . Traffic pollution . Dispersion modeling . Izmir Introduction The street canyon environment has been pointed out as a “hot spot” in terms of air pollution since traffic is the major pollutant source sector in the biggest cities. As a consequence, many recent studies have focused on the modeling and monitoring of air quality in urban street canyons (Hirtl and Baumann-Stanzer 2007; Ketzel et al. 2007; Vardoulakis et al. 2007; Assael et al. 2008; Berkowicz et al. 2008; Zhou and Levy 2008; Murena et al. 2009; Taseiko et al. 2009). Various street canyon models have been developed to evaluate the impact of traffic emissions in street canyons. These models can be categorized as more sophisticated numerical modeling tools, such as Computational Fluid Dynamics (CFD) models or as simpler parametric modeling tools (Operational Street Pollution Model [OSPM], STREET, CPBM, etc.). Numerical CFD models need many parameters to describe street canyons, high spatial resolutions such as a few meters, more computer power, and more time to complete calculations in comparison to simpler parametric models (Vardoulakis et al. 2003; Berkowicz et al. 2008; Assael et al. 2008; Murena et al. 2009). The parametric models are widely used to estimate the concentrations of various pollutants in street canyons. These models are based on the characteristics of flow conditions, street geometry, and meteorological conditions in a street. Pollution levels in a street are calculated using traffic emissions in this particular street only, while contributions from the surrounding streets and other sources are treated as background pollution. These models approach T. Elbir (*) : M. Kara : A. Bayram : H. Altiok : Y. Dumanoglu Department of Environmental Engineering, Tinaztepe Campus, Dokuz Eylul University, 35160 Izmir, Turkey e-mail: tolga.elbir@deu.edu.tr Air Qual Atmos Health (2011) 4:121–131 DOI 10.1007/s11869-010-0080-9