Simulation of Microclimate and PM2.5 Dispersion in Typical Urban Parks in Beijing Based on the ENVI-Met Model

With rapid advancements in industrialization and urbanization, Beijing is increasingly facing severe urban heat island effects and air pollution, particularly from haze. Urban parks play a vital role in improving the local microclimate and facilitating the dispersion of fine particulate matter (PM2.5). However, most existing studies have focused primarily on the cooling and humidifying functions of urban parks, with limited attention given to the combined assessment of their regulatory effects on both the microclimate and air pollutants. Moreover, the influence of seasonal variation on these ecological services has rarely been systematically examined. To address these research gaps, this study selected three representative urban parks in Beijing and conducted a quantitative analysis of four key environmental parameters—air temperature, relative humidity, wind speed, and PM2.5 concentration—during spring, summer, and winter. Using Landsat remote sensing imagery and the ENVI-met v3.1 computational fluid dynamics (CFD) model, this study simulated dynamic changes in the microclimate and pollutant dispersion within parks. Model feasibility was evaluated through validation metrics and comparisons with field observations. The results show the following: (1) Urban parks significantly improve the local microclimate and reduce PM2.5 concentrations, with the most notable effects observed in summer when the ecological functions of vegetation are at their peak. (2) The ENVI-met model can be used to simulate the microclimate and PM2.5 dispersion in the three parks, with the highest simulation accuracy occurring during the summer season. This study provides valuable insights for urban park planning in Beijing, particularly for developing strategies to enhance microclimatic conditions and mitigate air pollution.