Differences in quantity and composition of leaf particulate matter and morphological structures in three evergreen trees and their association in Harbin, China. (September 2019)

• Record Type: Journal Article
• Authors: Xu, Haijun; Wang, Wenjie; Wang, Huimei; Sun, Yufeng; Zhong, Zhaoliang; Wang, Shurui
• Is Part Of: Environmental pollution. Volume 252(2019):Part B
• Page Start: 1772
• Page End: 1790
• Publication Date: 2019-09
• Subjects: PM adsorption -- Leaf characteristics -- Functional group traits -- Mineral composition -- Heavy-metal removal -- Urban trees configuration; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.06.124
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Urban trees have been assumed to effectively clean air particulate matter (PM), while the inter-species differences are not yet well defined, especially the PM chemical composition. In this study, PM from leaf surface and wax layer of 3 evergreen tree species (Juniper: Juniperus rigida ; Black pine: Pinustabuliformis var. mukdeais ; Spruce: Picea koraiensis ) were used for finding differences in PM adsorption and its compositional traits (characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum and Inductively coupled plasma-optical emission spectrometry). Possible improvement in PM removal was also evaluated by a detail whole city tree census and different scenarios of species adjustment data. We found that: 1) the amount of PM on juniper leaves was 5.73 g m −2, 2–2.5-fold higher than black pine and spruce ( p < 0.05). Of them, 38.73%, 38.22%, and 23.11% were in the wax layer. 2) Compared with the explicit interspecies differences in PM quantity, more complex interspecies difference showed different patterns for different compositional traits. In general, leaf surface PM had higher O, Si, Al, Fe, N, Pb, Cu, Ni, Cr, and Cd, while the wax PM had higher C and Na contents ( p < 0.05). 3) Association ordination found that the smaller leaf size, lower leaf water content, higher leaf area per unit mass, higher wax content, and larger stomatal openness aligned with the more PM adsorption by leaf, together with the higher amounts of CO stretching, O, Si, Al, N, heavy metals of Pb, Cu, Ni, Cr, and Cd in PM. 4) Compared with the other 2 species, increase of juniper percentage in urban forests is more effective for maximizing PM removal from air, accompanying more heavy metal removal but less crystalized minerals in PM. Our findings highlight that proper species configuration in urban afforestation could maximize the air PM removal capacity. Graphical abstract: Image 1 Highlights: XRD, XPS, IR, and ICP were used to characterize PM composition. Large interspecies variations were found in PM quantity and composition traits. Wax layer could deposit PM, comparable to that at leaf surface. Leaf morphology strongly associated with PM composition traits and quantity. Proper species adjustment could enlarge PM removal several-folds.