This study presents the establishment and the application of
a modified semi-empirical model based on the box approach for
the prediction of PM
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H.-d. He et al. / Atmospheric Environment 43 (2009) 6336–6342 6341
concentrations at an urban traffic intersec-
tion in Hong Kong. In the study, the microscopic traffic flow at the
intersection is simulated firstly to obtain the instantaneous velocity
and acceleration. Hence, the vehicle emission during the greenlight
period in street canyon is then calculated for the application of
the semi-empirical box model. To evaluate the performance of the
model, it was firstly applied within a sunny day to remove the
influence of weather condition and then further testified between two sunny days. From the evaluation and predication results, the
semi-empirical model with instantaneous velocity and acceleration
performed well in all case except certain values were overestimate
or underestimated. The advantage of using instantaneous velocity
and acceleration on semi-empirical box model is to attempt to
describe the traffic flow and calculate the vehicle emission with
a more realistic representation from microscopic point of view.
Through application of the improved model on two situations, the
attempt is proved to be significant and informative. It is verified to
be a practical alternative approach for evaluating the PM
dispersion at urban traffic intersection with a reasonable accuracy.