Determination of the Pm10 Urban Threshold Velocity of Re-suspension in an Inner Part of Urban Area

In this paper authors focus on determination of the threshold velocity of re-suspension for particles 10 m in an urban street canyon with two-way traffic. The urban wind threshold velocity of re-suspension is derived from a long-term measurement carried out in the city of Brno. A numerical modelling based on the finite volume method is used for a detail study of the relation between a wind velocity above buildings roofs and an air velocity just above the ground surface. The predicted threshold air velocity of re-suspension at the bottom part of the studied street canyon is compared with two theoretical studies on particle re-suspension. Calculations are carried out for perpendicular, longitudinal and oblique (45°) wind direction with and without inclusion of traffic dynamic. To simulate traffic, an original model developed previously by the authors is used that takes into account traffic density, speed of cars and number of traffic lanes.