Research on PM10 diffusion and distribution of moving vehicle in street canyon based on dynamic mesh

Particulate matter (PM) produced by moving vehicles causes the deterioration of urban air quality and seriously endangers the health of residents. By considering PM10 as discrete phase and adopting dynamic mesh updating technology, a mathematical model of PM10 dispersion in three-dimensional ideal street canyon is established to evaluate the contribution of vehicle-induced turbulence to the dispersion of PM10. The dynamic spatial distribution characteristics of PM10 are analyzed when the average vehicle speed is 60 km/h, 50 km/h and 40 km/h. PM10 diffuses outwards in the form of alternating turbulent vortices on both sides, and its diffusion law is mainly affected by vehicle-induced turbulence. After a quarter of total moving time, the peak concentration of PM10 on the horizontal monitoring line drops to 0.3%, 14.4% and 10.7%, respectively, and the peak concentration of PM10 on the vertical monitoring line drops to 0.03%, 9.6% and 4.3%, respectively. For car drivers, they need to maintain a following distance of more than 3.5 m. For roadside pedestrians, they only need to walk on the sidewalk as required. This paper studies the diffusion of PM10 under different moving conditions from microscopic perspective, and provides a theoretical basis for urban development of traffic emission control measures.