The notable finding of this study is that the more NOx and PM10 concentrations increase, the reduction achieved by urban parks becomes more significant. Therefore, during the winter, under stable synoptic conditions when air pollution concentrations of NOx, PM10, and CO level were high, standard deviations of NOx and PM10 were high too, exhibited by high-frequency variations especially at the street canyon. These may be caused by a combination of heavy traffic during rush-hours (morning and evening) and low wind velocity (0e1.0 m/s).