Gaseous elemental mercury concentration in atmosphere at urban and remote sites in China

Abstract

An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory (CGAWBO) in Mt. Waliguan of remote continental area of China. High temporal resolved data were obtained using automated mercury analyzer RA-915+. Results showed that the overall hourly mean Hgo concentrations in Mt. Waliguan were 1.7-+1.1 ng/m3 in summer and 0.6+0.08 ng/m' in winter. The concentration in Yangtze Delta regional site was 5.4+4.1 ng/m3, which was much higher than those in Waliguan continental background area and also higher than that found in North America and Europe rural areas. In Beijing urban area the overall hourly mean Hg" concentrations were 8.3+3.6 ng/m3 in winter, 6.5+5.2 ng/m3 in spring, 4.9k3.3 ng/m3 in summer, and 6.7*3.5 ng/m3 in autumn, respectively, and the concentration was 13.5k7.1 ng/m' in Guangzhou site. The mean concentration reached the lowest value at 14:O and the highest at O2:OO or 20:OO in all monitoring campaigns in Beijing and Guangzhou urban areas, which contrasted with the results measured in Yangtze Delta regional site and Mt. Waliguan. The features of concentration and diurnal variation of Hg" in Beijing and Guangzhou implied the importance of local anthropogenic sources in contributing to the high Hg" concentration in urban areas of China. Contrary seasonal variation patterns of Hg" concentration were found between urban and remote sites. In Beijing the highest Hg'concentration was in winter and the lowest in summer, while in Mt. Waliguan the Hgo concentration in summer was higher than that in winter. These indicated that different processes and factors controlled Hg" concentration in urban, regional and remote areas.

Characteristics and potential sources of atmospheric mercury at a subtropical near‐coastal site in East China

“…The highest monthly mean occurred in December (4.7 ng m À3 ). The higher TGM concentration in the cold season and lower concentration in the warm season are consistent with previous results at sites influenced by local anthropogenic Hg emissions in China [Feng et al, 2002[Feng et al, , 2003[Feng et al, , 2004Fu et al, 2012c;Wang et al, 2007]. This is in contrast to TGM concentrations observed at sites influenced by long transport [Fu et al, 2012a], during which dilution and mixing by air masses can influence the dispersion of Hg plumes.…”

“…Atmospheric Hg emissions in Shanghai and Zhejiang Provinces were 10.5 Mg and 21.0 Mg in 2003 [Wu et al, 2006]. The concentration of GEM at Shuangqiao farm in Jiaxing County (another observational site in the Yangtze River Delta, 140 km northwest of DAO) was 5.4 ± 4.1 ng m À3 as reported by a previous study [Wang et al, 2007].…”

“…The TGM concentration was 3.3 ± 1.4 ng m À3 , higher than the concentrations observed at most remote sites in Europe and U.S. (<2 ng m À3 ) [Choi et al, 2008;Engle et al, 2010;Kock et al, 2005;Sigler et al, 2009] and in SW and NW China (1.6-2.6 ng m À3 ) [Fu et al, 2010[Fu et al, , 2012a[Fu et al, , 2012b, but lower than the concentrations observed at urban sites in China (e.g., 4.9-8.3 ng m À3 in Beijing, 13.5 ± 7.1 ng m À3 in Guangzhou, 5.4 ± 4.1 ng m À3 in Yangtze River Delta, and 3.8 ± 1.3 ng m À3 in Ningbo) [Wang et al, 2007;Nguyen et al, 2011]. The elevated mean concentration suggests the influence from local and regional Hg emissions, with possible contributions from industrial processes (including power plants, steel plants, and cement plants) and domestic heating in industrial/urban areas in Eastern China.…”

“…East China (including Shanghai, Anhui, Jiangsu, Zhejiang, Fujian, Jiangxi, and Shandong Provinces) is an important source region of atmospheric Hg in China, constituting approximately 20% of the total emissions [Wu et al, 2006]. , 2012bWang et al, 2007]. In particular, there are few long-term atmospheric Hg observations in the Yangtze River Delta region [Wang et al, 2014;Zhu et al, 2014].…”

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

“…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).…”