Vegetation-related dry deposition of global PM2.5 from satellite observations

• Published in: Journal of geographical sciences 2022-04, Vol.32 (4), p.589-604
• Main Authors: Feng, Huihui, Ding, Ying, Zou, Bin, Cohen, Jason Blake, Ye, Shuchao, Yang, Zhuolin, Qin, Kai, Liu, Lei, Gu, Xiaodong
• Format: Article
• Language: English
• Subjects: Air pollution; Air quality; Dry deposition; Earth and Environmental Science; Geographical Information Systems/Cartography; Geography; Land management; Land pollution; Nature Conservation; Outdoor air quality; Particulate matter; Physical Geography; Pollution sources; Remote Sensing/Photogrammetry; Vegetation
• ISSN: 1009-637X; 1861-9568
• DOI: 10.1007/s11442-022-1962-0

Vegetation plays an important role in the dry deposition of particles with significant spatial variability, but the magnitude remains unclear at the global scale. With the aid of satellite products, this study estimated the vegetation-related dry deposition of fine particulate matter (PM 2.5 ). Methodologically, dry deposition was first calculated using an empirical algorithm. Then, deposition on the leaf surface was estimated to evaluate the influence of vegetation. Our results showed that the mean deposition velocity ( V d ) of global PM 2.5 was 0.91×10 −3 µg·m −2 ·s −1 , with high velocities observed in sparsely vegetated regions because of the high friction velocity. Under the combined effect of the PM 2.5 mass concentration and deposition velocity, the global mean dry deposition reached 0.47 g·m −2 ·yr −1 . Global vegetation absorbed 0.26 g·m −2 ·yr −1 from PM 2.5 pollution sources, contributing 54.98% of the total dry deposition. Spatially, vegetation-related dry deposition was high in the Amazon, Central Africa and East China due to dense vegetation coverage or serious pollution. Temporally, the increasing trends were mainly in Central Africa and India because of worsening air pollution. The results of this study helped to clarify the impact of vegetation on air pollution, which supported related land management and planning for air quality improvement.