Comparison of measured and modelled traffic-related air pollution in urban street canyons

Abstract

The level of hazardous traffic pollutants, such as nitrogen dioxide (NO2), significantly increases in street canyons, which is a relevant determinant of assessing human exposure and health risks and deteriorates quality of urban air. The aim of the present study was to measure air pollution of NO2 by passive samplers in five street canyon sites with different traffic and building characteristics during two-week measurement periods in each season and to compare measured NO2 concentrations with models using the Airviro street canyon model. The data of meteorological parameters, street canyon orientation and urban background air pollution were taken into account. The study results showed that the highest measured and modelled concentrations of NO2 in street canyons were determined during spring and summer, and modelled values were higher than those measured with passive samplers, while during winter and autumn the results were vice versa. The greatest difference between measured and modelled concentrations of NO2 was determined in winter, while the highest degree of agreement was assessed in summer. We found a strong positive correlation between the measurements and modelling results. The research demonstrates the importance of considering the urban micro environments such as street canyons for the effective assessment of human exposure to transport-related emissions.