Factors influencing atmospheric wet deposition of trace elements in rural Korea Jung-Eun Kim a , Young-Ji Han a, ⁎, Pyung-Rae Kim a , Thomas M. Holsen b a Department of Environmental Science, College of Natural Science, Kangwon National University, 192‐1 Hyoja-2-dong, Chuncheon, Kangwon-do, 200‐701, Republic of Korea b Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Ave., Potsdam, NY, 13699‐5710, USA article info abstract Article history: Received 6 December 2011 Received in revised form 7 March 2012 Accepted 23 April 2012 In this study, precipitation samples were collected in a rural area of Korea between August 2006 and July 2009. The volume weighted mean (VWM) concentrations showed distinct seasonal variations, having high values in winter and low values in summer. Westerly winds that prevailed during the cold season were associated with enhanced concentrations of trace elements in precipitation. Based on back-trajectory analysis these samples were often associated with industrialized areas of China and metropolitan areas of Korea. Wet deposition fluxes of trace elements were inversely related to the VWM concentration, having high values in the summer due to the large precipitation depths. However, the largest wet deposition fluxes were observed for snow events despite their low precipitation depth, indicating that snow was a more efficient scavenger of trace elements than rain. © 2012 Elsevier B.V. All rights reserved. Keywords: Precipitation Wet deposition Trace element Snow Rural area 1. Introduction In Korea the concentration of atmospheric fine particles has increased or been relatively consistent despite many efforts (such as industrial transfer and fuel conversion) to improve air quality, while the concentrations of other pollutants such as sulfur dioxide and carbon monoxide have steadily decreased over the past few decades. Atmospheric particles consist of various chemical constituents including ionic and carbonaceous compounds, and other trace ele- ments (Yubero et al., 2010). Trace elements including toxic heavy metals are emitted from both natural and anthropo- genic sources. While crustal elements including Al, Mn, Si, and Fe are emitted from windborne dust and volcanoes, elements such as Cr, Cu, Zn, and Pb are mainly emitted from anthropogenic sources including transportation, industrial processes, and fuel combustion (Danielyan, 2010). Source types often determine the size distribution of aerosol; accumulation mode (0.1–1 μm) is often the result of combus- tion of fossil fuels and high temperature processes while elements in the coarse mode (>1 μm) are usually produced by mechanical processes such as wind or erosion (Seinfeld and Pandis, 2006). Therefore, the elements in the accumulation mode (such as Cr, Cu, and Zn) can remain in the atmosphere for days or weeks and thus be subject to long-range transboundary transport. As trace elements are deposited into surface water and the terrestrial environment through dry and wet depositions, they are associated with adverse human and wildlife health effects. Wet deposition of gaseous pollutants occurs through both rainout (referring to in-cloud scavenging) and washout (referring to below-cloud scavenging); however, particles are mainly deposited via washout as a raindrop collides with them. Heavy metals emitted by combustion processes usually have relatively high solubility and reactivity, dissolving readily in rain (Nriagu, 1984; Migon et al., 1997; Hou et al., 2005). Wet deposition of As, Cd, Cr and Pb has been a major concern due to their potential carcinogenic effects on humans and adverse effect on ecosystem health (Mijic et al., 2010). Atmospheric Research 116 (2012) 185–194 ⁎ Corresponding author at: Department of Environmental Science, 192‐1, Hyoja-2-dong, Kangwon National University, Chuncheon, Kangwon-do, 200‐ 701, Republic of Korea. Tel.: +82 33 250 8579; fax: +82 33 251 3991. E-mail address: youngji@kangwon.ac.kr (Y.-J. Han). 0169-8095/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.atmosres.2012.04.013 Contents lists available at SciVerse ScienceDirect Atmospheric Research journal homepage: www.elsevier.com/locate/atmos