Air PM10,2.5 Removal by Urban Green Space Under Urban Realistic Stressors

Abstract

Urbanization has significantly altered the ecological resources, functions, and services, thereby imposing specific constraints on particulate matter (PM) mitigation through green spaces. To investigate the effect of green spaces on mitigating PM10,2.5 under multiple urban stressors, this study employed combined remote sensing imagery and small-scale quantitative measurements to identify the PM within green space and street tree, and their PM differences with the square underlying surface according to a continuous scale of 60~3000 m. The results indicated that urban stressors significantly influenced air PM10 and PM2.5 mitigation, with stressors LST (land surface temperature) and RD (traffic road density) as key stressors on air PM10, while LST, ISA (impervious surface area), BH (building height), NDVI (normalized difference vegetation index), GA (green space area), and WA (water body area) were key stressors on air PM2.5. Furthermore, stressors exhibited a significant scale effect on air PM10,2.5 mitigation; for air PM2.5, stressors ISA, RD, BH and BD (building density) had a notable impact on air PM2.5 mitigation at 1500~3000 m scales, while NDVI, GA, and WA showed a significant impact at 450~600 m. For air PM10, stressors ISA, BH, NDVI, and GA revealed a continuous scale effect, with the key scales occurring at 450 m and 3000 m. In summary, urbanization stressors can combine to affect air PM10 and PM2.5 mitigation by green spaces, especially at different spatial scales, to provide practical guidance for urban planning.