Water-soluble iron in PM2.5 in winter over six Chinese megacities: Distributions, sources, and environmental implications. (1st December 2022)

• Record Type: Journal Article
• Authors: Wang, Xin; Shen, Zhenxing; Huang, Shasha; Che, Huizheng; Zhang, Leiming; Lei, Yali; Sun, Jian; Shen, Guofeng; Xu, Hongmei; Cao, Junji
• Is Part Of: Environmental pollution. Volume 314(2022)
• Publication Date: 2022-12-01
• Subjects: Water-soluble iron -- Spatial distributions -- Source identification -- Reactive oxygen species; 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.2022.120329
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Water-soluble iron (ws-Fe) in PM2.5 plays a crucial role in biogeochemical cycles and atmospheric chemical processes. The anthropogenic sources of ws-Fe have attracted considerable attention owing to its high solubility. However, few studies have investigated the content of PM2.5 ws-Fe in the urban environment. In the present study, we characterized the spatial distributions of ws-Fe in six Chinese megacities in the winter of 2019. Furthermore, we investigated the speciation of PM2.5 ws-Fe (ws-Fe(II) and ws-Fe(III)), potential sources of ws-Fe, and association between ws-Fe and particle-bound reactive oxygen species (ROS). Higher ws-Fe concentrations were observed in northern cities (Harbin, Beijing, and Xi'an) than in southern cities (Chengdu, Wuhan, and Guangzhou). Moreover, atmospheric ws-Fe concentrations in urban China were several folds higher than those in urban areas of the United States and several orders of magnitude higher than those in remote oceans, indicating that China is a key contributor to global atmospheric ws-Fe. The dominant form of ws-Fe was ws-Fe(III) in Beijing, whereas ws-Fe(II) was more abundant in the other five cities. The concentrations of ws-Fe and ws-Fe(II) concentrations increased with increasing PM2.5 levels in all the six cities, however, we did not observe any consistent pattern of ws-Fe(III) concentration. Biomass burning was a dominant source of ws-Fe in all cities except Beijing. A strong positive correlation was observed between particle-bound ROS content and ws-Fe; this finding is consistent with those of previous studies indicating that ws-Fe in PM2.5 notably influences atmospheric chemical processes and human health. Graphical abstract: Image 1 Highlights: Higher water-soluble Fe concentrations were observed in northern than southern Chinese cities. Biomass burning was a major source of water-soluble Fe in the five Chinese cities except Beijing. A strong association between water-soluble Fe and particle-bound reactive oxygen species was observed.