Articles | Volume 16, issue 6
Research article
30 Mar 2016
Research article |  | 30 Mar 2016

Atmospheric speciated mercury concentrations on an island between China and Korea: sources and transport pathways

Gang-San Lee, Pyung-Rae Kim, Young-Ji Han, Thomas M. Holsen, Yong-Seok Seo, and Seung-Muk Yi

Abstract. As a global pollutant, mercury (Hg) is of particular concern in East Asia, where anthropogenic emissions are the largest. In this study, speciated Hg concentrations were measured on Yongheung Island, the westernmost island in Korea, located between China and the Korean mainland to identify the importance of local and regional Hg sources. Various tools including correlations with other pollutants, conditional probability function, and back-trajectory-based analysis consistently indicated that Korean sources were important for gaseous oxidized mercury (GOM) whereas, for total gaseous mercury (TGM) and particulate bound mercury (PBM), regional transport was also important. A trajectory cluster based approach, considering both Hg concentration and the fraction of time each cluster was impacting the site, was developed to quantify the effect of Korean sources and out-of-Korean sources. This analysis suggests that contributions from out-of-Korean sources were similar to Korean sources for TGM whereas Korean sources contributed slightly more to the concentration variations of GOM and PBM compared to out-of-Korean sources. The ratio of GOM/PBM decreased when the site was impacted by regional transport, suggesting that this ratio may be a useful tool for identifying the relative significance of local sources vs. regional transport. The secondary formation of PBM through gas-particle partitioning with GOM was found to be important at low temperatures and high relative humidity.

Short summary
This study was initiated to identify the sources affecting speciated mercury concentrations measured on the island located between mainland Korea and China. The results from various approaches consistently show that Korean sources are most important for gaseous oxidized form while for other Hg species regional transport was also important. It is also suggested that the secondary formation of particulate Hg becomes more important as the significance of long-range transport increased.
Final-revised paper