Differences in mass concentration and elemental composition of leaf surface particulate matter: Plant species and particle size ranges

Abstract

Leaf surface particulate matter (PM) is an optimal material for the environmental monitoring of urban green spaces Currently, most studies have looked at leaf surface PM, using only its mass concentration to investigate the dust retention capacity and mechanisms of different plant leaves. The elemental composition of leaf surface PM has been neglected as a reflection of the environment and its sources. Therefore, in this study, ten common plant species were selected from the Olympic Forest Park, an urban green space in Beijing, and the characteristics of leaf surface PM were analysed in depth in terms of mass concentration and elemental composition. The leaf surface PM mass concentration was first obtained by vacuum filtration (VF) method, and then the leaf surface PM attached to the filter membrane obtained from the previous step was used as experimental material to study its elemental composition using cold field emission scanning electron microscopy combined with energy dispersive X-ray spectroscopy (FESEM-EDS). The results show that (1) In terms of mass concentration, were Hemerocallis fulva, Poa pratensis, Acorus calamus, Typha orientalis, and Phragmites communis had better dust retention capacity; (2) The five most important elements deposited on the leaf surface of plants in Beijing were C, O, Mg, Al, and Si, with a total of 26 elements detected; (3) The particulate matter retained on the leaf surface of plants in Beijing was classified as Geogenic particles (57.70%) > Anthropogenic particles (22.30%) > Biogenic particles (20.00%). The results at this stage are expected to promote the in-depth understanding of plant leaf remediation of PM.