Estimating mercury emission outflow from East Asia using CMAQ-Hg

Abstract

Abstract. East Asia contributes to nearly 50% of the global anthropogenic mercury emissions into the atmosphere. Recently, there have been concerns about the long-range transport of mercury from East Asia, which may lead to enhanced dry and wet depositions in other regions. In this study, we performed four monthly simulations (January, April, July and October in 2005) using CMAQ-Hg v4.6 for a number of emission inventory scenarios in an East Asian model domain. Coupled with mass balance analyses, the chemical transport of mercury in East Asia and the resulted mercury emission outflow were investigated. The total annual mercury deposition in the region was estimated to be 821 Mg, with 396 Mg contributed by wet deposition and 425 Mg by dry deposition. Anthropogenic emissions were responsible for most of the estimated deposition (75%). The deposition caused by emissions from natural sources was less important (25%). Regional mercury transport budgets showed strong seasonal variability, with a net removal of RGM (7-15 Mg month −1 ) and PHg (13-21 Mg month −1 ) in the domain, and a net export of GEM (60-130 Mg month −1 ) from the domain. The outflow caused by East Asian emissions (anthropogenic plus natural) was estimated to be in the range of 1369-1671 Mg yr −1 , of which 50-60% was caused by emissions from natural sources. The emission outflow repCorrespondence to: C.-J. Lin (jerry.lin@lamar.edu) resented about 75% of the total mercury emissions in the region, and would contribute to 20-30% of mercury deposition in remote receptors.

Elemental mercury (Hg(0)) in air and surface waters of the Yellow Sea during late spring and late fall 2012: Concentration, spatial-temporal distribution and air/sea flux

“…The combination of this study and other measurements in the open ocean (Friedli et al, 2004;Ci et al, 2011d;Nguyen et al, 2011) and coastal regions (Nguyen et al, 2007;Ci et al, 2011a) suggests that the GEM concentrations in the Yellow Sea had a common spatial pattern with increased concentrations in the coastal region (2.5-3.5 ng m À3 ) and decreased concentrations in the open ocean (1.3-1.7 ng m À3 ). This phenomenon has also been successfully reproduced by modeling study (e.g., Lin et al, 2010). This indicates that the east of China has significant contribution to the atmospheric Hg pool downwind of East Asia.…”

“…Hg concentrations in various environmental samples (e.g., water, sediment, and organism) are elevated and the Hg contamination has posed a serious risk to this marine ecosystem (Liang et al, 2003;Luo et al, 2012). Recently, many modeling efforts have been made to explore the Hg cycling in East Asia (Shetty et al, 2008;Lin et al, 2010). However, the accuracy of the modeling result is difficult to evaluate because of limited field data, especially those related to marine system (Jaffe and Strode, 2008;Ci et al, 2012).…”

Observations of atmospheric mercury in China: a critical review

“…Lin et al (2010) simulated the dry deposition of Hg in East Asia using the CMAQ-Hg model. The results demonstrated a remarkable spatial distribution of dry deposition fluxes ranging from 10 to 150 µg m −2 yr −1 .…”

Temporal trend and sources of speciated atmospheric mercury at Waliguan GAW station, Northwestern China

“…Also, mean TGM concentrations of 1.72 and 1.66 ng m −3 were obtained from long-term measurements at Mace Head, Ireland and Zingst, Germany, respectively (Kock et al, 2005). Recently, many efforts have been devoted to model the spatial distributions of atmospheric Hg in Asia, mainly because this region constitutes of a very important portion of the global total anthropogenic Hg emissions (Seigneur et al, 2004;Selin et al, 2007;Lin et al, 2010). These modeling studies predicted relatively high surface ambient TGM concentrations in Eastern China and areas downwind Eastern China, which are consistent with many of the observations (Feng et al, 2005;Fu et al, 2010a, b;Ci et al, 2011).…”