Numerical Simulation of Atmospheric Pollutant Dispersion on Campus: Impacts of Wind Environment and Newly Constructed Buildings' Height.

Toluene, as a common organic solvent in academic laboratories in university campuses, poses potential exposure concerns to students and staff in university campuses. Hence, by using a computational fluid dynamics simulation, we investigated the dispersion characteristics of toluene at a campus in Guangzhou under meteorological conditions and the impact of newly constructed buildings on toluene concentrations. The numerical simulation results reveal that toluene is readily accumulated in the free movement area under the prevailing east wind, in the administrative area under the prevailing north-northeast wind, and in the teaching area under the prevailing south wind. Therein, the teaching buildings (TB3-TB6) possess the highest average concentration of toluene compared with other functional areas. In the presence of newly constructed buildings, the toluene concentrations are decreased under the south-southeast wind but are aggravated under the southeast wind. As the height increases, under south-southeast winds, the merging of vortex structures continuously reduces toluene concentrations at TB3 and TB4 and the expansion of the wake region rebounds the toluene pollution at TB5 and TB6; under southeast winds, the expanding vertical vortex structures aggravate toluene pollution at TB3 and TB5 but attenuate toluene pollution at TB4 and TB6. Our results reveal that the teaching areas of the target campus represent a critical zone for potential student exposure during summer and require particular attention. This study provides new insights into the coupled effects of prevailing wind conditions and campus morphology on VOC dispersion characteristics and improves the understanding of airflow pollutant interactions in complex campus environments.