Combined effects of Wind Speed and Greenspace Layouts on Particulate Matter Pollution: A Multiscale Study in the Zhengzhou Metropolitan Area

Abstract

Atmospheric particulate matter (PM) pollution is separately influenced by urban greenspaces and meteorological conditions. However, the mediating role of wind environment and the combined effect of greenspace pattern layouts and wind on PM pollution remains unclear. This study, conducted in the Zhengzhou metropolitan area (ZMA), which includes nine cities, utilized high-resolution satellite imagery, PM concentration data, and wind speed monitoring data from 2021. We investigated the combined effects of greenspace layouts and wind speed on PM2.5 and PM10 pollution, as well as their scale effects, by constructing Structural Equation Models (SEMs). The results demonstrated that wind speed mediated the impact of greenspace layouts on PM2.5 and PM10 concentrations across various scales. Greenspace layouts and wind speed exhibited more substantial combined effects on PM10 in comparison to PM2.5. The combined effects of greenspace layouts and wind speed on PM2.5 and PM10, in addition to the mediating effects of wind speed, varied significantly across scales. Accounting for the influence of urban wind speed, reducing the percentage of large greenspace patches at the 3-5km scales can significantly diminish PM10 pollution. Simplifying the morphology of greenspace patches at the 1-3km scales, coupled with enhancing the interconnectivity of greenspace patches and the percentage of greenspace at the 2-4km scales, and minimizing the clustering of greenspace patches at the 3-4km scales, such measures can effectively mitigate PM pollution by influencing wind speed. Our findings can provide new insights of incorporating local wind environment into the development of multi-scale greenspace landscape optimization strategies aimed at mitigating PM pollution in ZMA.