Particle resuspension from leaf surfaces: Effect of species, leaf traits and wind speed

Particles deposited on leaf surfaces can be resuspended back into the atmosphere, thus generating pollution diffusion and hazarding to human health. The net amount of particles resuspended depends on leaf traits and weather conditions, such as speed wind and leaf roughness. However, little is known about the influence of leaf traits of different tree species on particle resuspension under certain conditions. In this study, we chose 6 typical greening tree species from Northeast China and focused on four-leaf traits: roughness, contact angle, stomatal density, and groove width. The wind tunnel was used to measure particle resuspension from leaf surfaces at different wind speeds (1, 2, 3 m/s) and test duration (10, 20, 30 min). Subsequently, we investigated the cor-relation between particle resuspension and leaf traits. The results indicated that Abies holophylla had the highest resuspension fraction (61.38%), followed by Salix babylonica (58.05%), Populus alba (54.21%), Juniperus chinensis (53.59%), and Pinus tabuliformis (50.51%), while Robinia pseudoacacia displayed the lowest particle resuspension fraction (32.02%). Particle resuspension rates of the tested species ranged from (8.24 +/- 0.53) x 10-4/s to (2.65 +/- 0.51) x 10-4/s, which was found to increase with wind speed enhancement and decrease with duration extension. With increasing the wind speed, the Pinus tabuliformis, and Juniperus chinensis were more efficient than Salix babylonica, and Populus alba in avoiding particle resuspension. Roughness and stomatal density were a significant negative correlation with particle resuspension rates, which demonstrates that the leaf surface traits can affect the particle resuspension process. Finally, our results suggest that the main factors influencing particle resuspension from leaf surfaces are wind speed, roughness, and stomatal density, which will provide a scientific foundation for pollution diffusion in future studies.

Automated summary

This study investigates the influence of leaf traits of different tree species on particle resuspension and finds that wind speed, roughness, and stomatal density significantly affect the process.