How Does Leaf Surface Micromorphology of Different Trees Impact Their Ability to Capture Particulate Matter?

Particulate matter (PM), including PM10 and PM2.5, has a major impact on air quality and public health. It has been shown that trees can capture PM and improve air quality. In this study, we used two-way ANOVA to investigate the significance of micro-morphological leaf surface characteristics of green trees in capturing PM at different parks in Beijing. The results show that leaf structure significantly impacts the ability of plants to capture PM. Pinus tabuliformis Carr. and Pinus bungeana Zucc. were mainly impacted by the density of stomata, waxy cuticle, and epidermis, while the major contributor to PM retention in other test trees, including Acer truncatum Bunge, Salix matsudana Koid., Populus tomentosa Carr. and Ginkgo biloba Linn. was leaf roughness. There were significant variations in leaf-droplet contact angle (representative of leaf wettability) and the ability of trees to capture PM (p < 0.05): the bigger the contact angle, the less able the plant was to capture particulate matter.