Mercury in the atmosphere around Japan, Korea, and China as observed during the 2001 ACE‐Asia field campaign: Measurements, distributions, sources, and implications

Abstract

We report on mercury in the atmosphere of east Asia (Japan, Korea, and China) as measured from sea level to ∼7000 m during 16 research flights in the National Science Foundation (NSF)/National Center for Atmospheric Research (NCAR) C‐130 aircraft during the Asian Pacific Regional Aerosol Characterization Experiment (ACE‐Asia) campaign (http://saga.pmel.noaa.gov/aceasia/). The air at all altitudes contained concentrations of atmospheric mercury above the global background. The atmosphere was highly stratified with plumes originating from massive dust storms carried out of China, from local industrial pollution, from volcanoes, and, less well defined, from biomass burning. Most often the air masses were mixtures, e.g., dust layers contained anthropogenic emissions or volcanic plumes were embedded in anthropogenic pollution; thus the total data set showed no significant correlations of gaseous mercury with the most common anthropogenic pollutants in the area (CO and SO2), but good correlations were observed for identifiable plumes. Highest mixing ratios for gaseous elemental mercury (GEM) were found in industrial plumes exiting China (∼6.3 ng/m3), Korea (∼3 ng/m3), and Japan (∼3 ng/m3). The core of the plume from Miyake Jima volcano contained ∼3.7 ng/m3 of GEM. Crustal mercury was also present, emitted and subsequently deposited during the outbreak of the spring dust storms. Some of the nondust aerosols contained soluble mercury in highly variable ratios with the gas‐phase mercury contained in the same plume. Preliminary estimates for the export from China are 5–15 t of crustal mercury during the dust storms, ∼150 t/yr of gas‐phase mercury from biomass/biofuel combustion, and ∼600 t/yr from industrial sources, mostly from coal combustion. Gaseous mercury is a useful tracer for industrial, volcanic, and biomass‐burning sources, but in most cases, robust plume identification required one or more cotracers. Because of the inertness of GEM and the ease of its measurement it is well suited for the tracking of long‐range transport.

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

“…This pattern is consistent with our summer cruise (Ci et al, 2011d) and two shipboard measurements from Weihai and Qingdao in the Shandong Peninsula (China) to Incheon (South Korea) crossing the north of the Yellow Sea (Nguyen et al, 2011). 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).…”

“…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). At present, most atmospheric Hg measurements focused on the coastal region of East Asia (e.g., Wang et al, 2007;Ci et al, 2011b;Nguyen et al, 2010;Xiu et al, 2009), but the investigations focusing on the open ocean are limited (Friedli et al, 2004;Ci et al, 2011d;Nguyen et al, 2011;Fu et al, 2010;Tseng et al, 2012;Sheu et al, 2013). The lack of Hg knowledge in the open ocean of East Asia has become a critical barrier to the current understanding of the regional and global Hg cycles (Jaffe and Strode, 2008;Ci et al, 2012).…”

Observations of atmospheric mercury in China: a critical review

“…For instance, measurements of atmospheric GEM in Seoul, Korea, showed that approximately 79 % of the high-GEM events were related to air masses originating from China (Choi et al, 2009). Flight measurements in the free troposphere over the Asia Pacific region also showed evidence of GEM outflow (Friedli et al, 2004). GEM emitted in China and East Asian countries can undergo intercontinental transport as suggested by the GEM / CO ratio measured at Mt.…”

“…This event was impacted by anthropogenic sources in southern China via strong convective processes (Lai et al, 2011). The emission plumes from mainland China on GEM were also detected in the free troposphere during the flights over East Asia (Friedli et al, 2004), which reported several strong GEM pollution events with concentrations exceeding 2.5 ng m −3 (up to 6.3 ng m −3 ; Friedli et al, 2004). Figure 5 shows the seasonal variations of GEM concentration at ground-based remote sites in China.…”

Estimating mercury emission outflow from East Asia using CMAQ-Hg

“…Although preliminary measurement and modeling analyses suggested that mercury emission outflow from the region may be significant (Pan et al, 2006(Pan et al, , 2008Friedli et al, 2004;Weiss-Penzias et al, 2007), there were few studies that provided detailed quantitative assessments. One approach to study regional emission outflow of air pollutants is to construct the mass budget of the pollutant of interest (Lamborg et al, 1995;Moussiopoulos et al, 2004).…”