Characteristics of atmospheric Total Gaseous Mercury (TGM) observed in urban Nanjing, China

Zhu, Jialei; Wang, T.; Talbot, R. W.; Mao, Huiting; Hall, Casey B.; Yang, Xu; Fu, Congbin; Zhuang, Bingliang; Li, S.; Han, Yong; Huang, Xing

doi:10.5194/acp-12-12103-2012

Cited by 86 publications

(98 citation statements)

References 67 publications

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“…In Guiyang (southwestern China) and Xiamen (southeastern China), monthly mean GEM concentrations were significantly higher (t test: p < 0.05 for both) in cold seasons than that in warm seasons (Feng et al, 2004;Xu et al, 2015). In contrast, monthly mean GEM concentrations in Nanjing (eastern China) were found to be ∼ 60 % higher in warm seasons than cold seasons (t test: p < 0.05; Zhu et al, 2012). In Guangzhou (southern China), the lowest concentration occurred in summer and the maximum was observed in spring (∼ 22 % higher; Chen et al, 2013).…”

Section: Atmospheric Hg In the Free Troposphere And Lower Stratospherementioning

confidence: 82%

“…For example, the annual anthropogenic Hg emissions in Guiyang and Nanjing reached 1.75 t and 4.26 t, respectively . Large emissions of GEM from natural surfaces in the urban areas may also play a role for the elevated GEM concentrations Zhu et al, 2012). There is a clear spatial distribution pattern of GEM at urban sites (Fig.…”

Section: Atmospheric Dry Depositionmentioning

confidence: 99%

“…Urban areas in China are densely populated and heavily industrialized. The high energy demand and the presence of other large point sources (e.g., iron and steel production, non-ferrous metals smelting, cement production) contribute to the large Hg 0 emissions (Fu et al, 2011a;Zhu et al, 2012;Chen et al, 2013). For example, the annual anthropogenic Hg emissions in Guiyang and Nanjing reached 1.75 t and 4.26 t, respectively .…”

Section: Atmospheric Dry Depositionmentioning

confidence: 99%

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Observations of atmospheric mercury in China: a critical review

et al. 2015

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Abstract. China presently contributes the largest amount of anthropogenic mercury (Hg) emission into the atmosphere in the world. Over the past decade, numerous studies have been conducted to characterize the concentration and forms of atmospheric Hg in China, which provide insights into the spatial and temporal distributions of atmospheric Hg through ground-based measurements at widely diverse geographical locations and during cruise and flight campaigns. In this paper, we present a comprehensive review of the state of understanding in atmospheric Hg in China. Gaseous elemental mercury (GEM) and particulate-bound mercury (PBM) measured at the remote sites in China are substantially elevated compared to the background values in the Northern Hemisphere. In Chinese urban areas, the highly elevated GEM, PBM and gaseous oxidized mercury (GOM) were mainly derived from local anthropogenic Hg emissions, whereas regional anthropogenic emissions and long-range transport from domestic source regions are the primary causes of the elevated GEM and PBM concentrations at remote sites. Using 7-9 years of continuous observations at a remote site and an urban site, a slight increase in atmospheric GEM (2.4-2.5 % yr −1 ) was identified (paired samples test: p < 0.01), which is in agreement with the increasing domestic anthropogenic emissions. Anthropogenic GEM emission quantity in China estimated through the observed GEM / CO concentration ratios ranged from 632 to 1138 t annually over the past decade, 2-3 times larger than published values using emission activity data. Modeling results and filed measurements show dry deposition is the predominant process for removing Hg from the atmosphere, 2.5-9.0 times larger than wet deposition, due to the elevated atmospheric GEM and PBM concentrations that facilitate dry deposition to terrestrial landscapes. Further studies to reconcile the observed and simulated Hg concentrations, to understand the impact of domestic emission reduction on Hg concentration and deposition and to delineate the role of Hg emission and deposition of China in the global Hg biogeochemical cycle, are needed.

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Section: Atmospheric Hg In the Free Troposphere And Lower Stratospherementioning

confidence: 82%

Section: Atmospheric Dry Depositionmentioning

confidence: 99%

Section: Atmospheric Dry Depositionmentioning

confidence: 99%

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Observations of atmospheric mercury in China: a critical review

et al. 2015

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“…T. Zhang et al, 2012;Chen et al, 2013;Zhu et al, 2014;Fu et al, 2015bFu et al, , 2016Ma et al, 2016). (Wang, 2006;Fu et al, 2011Fu et al, , 2015bHuang et al, 2012;Wang et al, 2012;Zhu et al, 2012Zhu et al, , 2014Huang et al, 2013;Xu et al, 2014Xu et al, , 2015. Figure 5 shows the comparison of wet deposition and litterfall fluxes of Hg as well as TGM/GEM, PBM, and GOM concentrations in China, North America, and Europe.…”

Section: Relative Contribution Of Wet and Litterfall Deposition To Tomentioning

confidence: 99%

Atmospheric wet and litterfall mercury deposition at urban and rural sites in China

Yang

Lang

et al. 2016

Atmos. Chem. Phys.

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Abstract. Mercury (Hg) concentrations and deposition fluxes in precipitation and litterfall were measured at multiple sites (six rural sites and an urban site) across a broad geographic area in China. The annual deposition fluxes of Hg in precipitation at rural sites and an urban site were 2.0 to 7.2 and 12.6 ± 6.5 µg m −2 yr −1 , respectively. Wet deposition fluxes of Hg at rural sites showed a clear regional difference with elevated deposition fluxes in the subtropical zone, followed by the temporal zone and arid/semi-arid zone. Precipitation depth is the primary influencing factor causing the variation of wet deposition. Hg fluxes through litterfall ranged from 22.8 to 62.8 µg m −2 yr −1 , higher than the wet deposition fluxes by a factor of 3.9 to 8.7 and representing approximately 75 % of the total Hg deposition at the forest sites in China. This suggests that uptake of atmospheric Hg by foliage is the dominant pathway to remove atmospheric Hg in forest ecosystems in China. Wet deposition fluxes of Hg at rural sites of China were generally lower compared to those in North America and Europe, possibly due to a combination of lower precipitation depth, lower GOM concentrations in the troposphere and the generally lower cloud base heights at most sites that wash out a smaller amount of GOM and PBM during precipitation events.

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“…The sketch map of the site (not shown) is the same as Fig. 1 of Zhu et al (2012). The black carbon aerosol mass concentration and aerosol absorption coefficient were derived from the measurements using the 7-channel Aethalometer (model AE-31, Magee Scientific, USA).…”

Section: Sampling Station and Instrumentsmentioning

confidence: 99%

Absorption coefficient of urban aerosol in Nanjing, west Yangtze River Delta, China

et al. 2015

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Abstract. Absorbing aerosols can significantly modulate short-wave solar radiation in the atmosphere, affecting regional and global climate. The aerosol absorption coefficient (AAC) is an indicator that assesses the impact of absorbing aerosols on radiative forcing. In this study, the near-surface AAC and absorption Ångström exponent (AAE) in the urban area of Nanjing, China, are characterized on the basis of measurements in 2012 and 2013 using the seven-channel Aethalometer (model AE-31, Magee Scientific, USA). The AAC is estimated with direct and indirect corrections, which result in consistent temporal variations and magnitudes of AAC at 532 nm. The mean AAC at 532 nm is about 43.23 ± 28.13 M m −1 in the urban area of Nanjing, which is much lower than that in Pearl River Delta and the same as in rural areas (Lin'an) in Yangtze River Delta. The AAC in the urban area of Nanjing shows strong seasonality (diurnal variations); it is high in cold seasons (at rush hour) and low in summer (in the afternoon). It also shows synoptic and quasi-2-week cycles in response to weather systems. Its frequency distribution follows a typical log-normal pattern. The 532 nm AAC ranging from 15 to 65 M m −1 dominates, accounting for more than 72 % of the total data samples in the entire study period. Frequent high pollution episodes, such as those observed in June 2012 and in winter 2013, greatly enhanced AAC and altered its temporal variations and frequency distributions. These episodes are mostly due to local emissions and regional pollution. Air masses flowing from northern China to Nanjing can sometimes be highly polluted and lead to high AAC at the site. AAE at 660/470 nm from the Schmid correction (Schmid et al., 2006) is about 1.56, which might be more reasonable than from the Weingartner correction (Weingartner et al., 2003). Low AAEs mainly occur in summer, likely due to high relative humidity (RH) in the season. AAC increases with increasing AAE at a fixed aerosol loading. The RH-AAC relationship is more complex. Overall, AAC peaks at RH values of around 40 % (1.3 < AAE < 1.6), 65 % (AAE < 1.3 and AAE > 1.6), and 80 % (1.3 < AAE < 1.6).

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Characteristics of atmospheric Total Gaseous Mercury (TGM) observed in urban Nanjing, China

Cited by 86 publications

References 67 publications

Observations of atmospheric mercury in China: a critical review

Observations of atmospheric mercury in China: a critical review

Atmospheric wet and litterfall mercury deposition at urban and rural sites in China

Absorption coefficient of urban aerosol in Nanjing, west Yangtze River Delta, China

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