Modeling airflow dynamics and their effects on PM_2.5 concentrations in urban ventilation corridors of Hangzhou

Urban Ventilation Corridors (UVCs) have been shown to effectively mitigate the urban heat island effect and enhance air quality. However, the simulation of large-scale UVCs airflow and its impact on fine particulate matter (PM_2.5) remains insufficiently explored without resorting to complex aerodynamic calculations. This study introduces a novel circuit-theoretic approach that integrates the Ventilation Potential Coefficient (VPC) and the Ventilation Resistance Coefficient (VRC). This method is combined with Local Climate Zone (LCZ) maps to analyze the internal attributes of UVCs and their relationship with PM_2.5 concentrations both within UVCs and in non-UVCs areas. The results show that: (1) UVCs are more effective at reducing PM_2.5 concentrations compared to non-UVC areas, with an average reduction of 25.2 % more than in non-UVC areas. The airflow simulation value for UVCs exhibits a nonlinear relationship with PM_2.5 concentration, showing an increase in PM_2.5 below 0.4 and a significant decrease above 0.6. (2) UVCs are predominantly composed of natural LCZs, which make up 71 % of the total area. Among these, LCZ 1, LCZ 10, and LCZ E show the highest PM_2.5 concentrations. Natural LCZs generally have lower average PM_2.5 levels compared to LCZs of built-up areas, with LCZ A demonstrating the lowest PM_2.5 concentration, showing a notable difference of 5.38 μg/m³. (3) Within UVCs, natural LCZs provide the most substantial PM_2.5 reduction, with LCZ E reducing PM_2.5 concentrations by up to 2.78 μg/m³ compared to non-UVCs areas. These findings offer a scientific foundation for the systematic planning and pollutant control of UVCs.