Sources and outflows of atmospheric mercury at Mt. Changbai, northeastern China

Abstract Atmospheric gaseous elemental mercury (GEM), particulate bound mercury (PBM), and gaseous oxidized mercury (GOM) were continuously measured at a remote site in northeastern China from July 2013 to July 2014. Mean (±1SD) concentrations of the hourly data of GEM, PBM, and GOM were 1.68 ± 0.47 ng m −3 , 16.6 ± 15.2 pg m −3 , and 5.4 ± 6.4 pg m −3 , respectively. Concentration-weighted trajectory (CWT) analysis suggested that the potential source regions of GEM and GOM observed at this site were northern and eastern China. GEM and GOM CWT values significantly correlated with anthropogenic Hg emissions, suggesting that long-range transport of anthropogenic Hg emissions played an important role in GEM and GOM pollutions in remote areas of northeastern China. On the other hand, long-range transport of anthropogenic PBM emissions from eastern and northeastern China combined with large-scale biomass burning in Northeast Asia likely dominated PBM pollution. Principal component analysis (PCA) results, making use of the combined data sets of speciated atmospheric Hg, trace elements, and meteorological parameters, suggested that coal combustion and non-ferrous metal smelting contributed significantly to all the Hg species at this site, while the other anthropogenic sources in China also had a major impact on GEM. Forward air mass trajectory analysis revealed that outflows of GEM from northeastern China may have a potential impact on GEM pollutions in remote and oceanic areas in Northeast Asia.