Temporal Trend and Spatial Distribution of Speciated Atmospheric Mercury Emissions in China During 1978–2014

Wu, Qingru; Li, Guoliang; Liang, Sai; Lin, Che‐Jen; Wang, Yafei; Cai, Siyi; Liu, Kaiyun; Hao, Jiming

doi:10.1021/acs.est.6b04308

Cited by 277 publications

(275 citation statements)

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“…Atmospheric GEM concentrations (the average concentration at two heights) were lower during spring and summer and higher in winter and fall, with an annual average value of 3.64 ng m −3 (1.89-6.26 ng m −3 , 5-95 % confidence interval) at site QYZ ( , 2014a). Although there were no major anthropogenic mercury emission sources near the QYZ station, the high concentration may be attributed to regional residential coal combustion (Wu et al, 2016) and high background GEM concentration in China (Fu et al, 2015). The annual average GEM concentration at station HT was 5.93 ng m −3 (2.46-11.6 ng m −3 , 5-95 % confidence interval), even higher than that at station QYZ.…”

Section: Hourly and Daily Variations In Gem Concentrations And Fluxesmentioning

confidence: 99%

“…China is currently the world's top emitter of anthropogenic Hg, with a value of 538 t in 2010 and 530 t in 2014 (Wu et al, 2016), which has resulted in an elevated Hg deposition to terrestrial ecosystem and thus Hg accumulation in land surface. Given that forest is likely to have large GEM re-emission of legacy Hg stored through old deposition, it is important to know the role of forests in China in global Hg transport and cycles.…”

Section: Introductionmentioning

confidence: 99%

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Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China

Luo

Wang

et al. 2018

Atmos. Chem. Phys.

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Abstract. Mercury (Hg) exchange between forests and the atmosphere plays an important role in global Hg cycling. The present estimate of global emission of Hg from natural source has large uncertainty, partly due to the lack of chronical and valid field data, particularly for terrestrial surfaces in China, the most important contributor to global atmospheric Hg. In this study, the micrometeorological method (MM) was used to continuously observe gaseous elemental mercury (GEM) fluxes over forest canopy at a mildly polluted site (Qianyanzhou, QYZ) and a moderately polluted site (Huitong, HT, near a large Hg mine) in subtropical south China for a full year from January to December in 2014. The GEM flux measurements over forest canopy in QYZ and HT showed net emission with annual average values of 6.67 and 0.30 ng m −2 h −1 , respectively. Daily variations of GEM fluxes showed an increasing emission with the increasing air temperature and solar radiation in the daytime to a peak at 13:00, and decreasing emission thereafter, even as a GEM sink or balance at night. High temperature and low air Hg concentration resulted in the high Hg emission in summer. Low temperature in winter and Hg absorption by plant in spring resulted in low Hg emission, or even adsorption in the two seasons. GEM fluxes were positively correlated with air temperature, soil temperature, wind speed, and solar radiation, while it is negatively correlated with air humidity and atmospheric GEM concentration. The lower emission fluxes of GEM at the moderately polluted site (HT) when compared with that in the mildly polluted site (QYZ) may result from a much higher adsorption fluxes at night in spite of a similar or higher emission fluxes during daytime. This shows that the higher atmospheric GEM concentration at HT restricted the forest GEM emission. Great attention should be paid to forests as a crucial increasing Hg emission source with the decreasing atmospheric GEM concentration in polluted areas because of Hg emission abatement in the future.

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Section: Hourly and Daily Variations In Gem Concentrations And Fluxesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China

Luo

Wang

et al. 2018

Atmos. Chem. Phys.

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“…Scientists have made extensive efforts to quantify atmospheric THg emissions from direct anthropogenic sources and natural processes in China. 24,25 In total, it has been estimated that 530 Mg of THg was emitted into the air from direct anthropogenic sources in China in 2014, 24 while inputs from natural processes (including background source and reemission of legacy anthropogenic source) were 470 Mg/yr. 25 In recent papers, we have quantified that 110 Mg of THg was released from direct anthropogenic sources into the aquatic environment in China in 2015.…”

Section: Introductionmentioning

confidence: 99%

Impact of Water-Induced Soil Erosion on the Terrestrial Transport and Atmospheric Emission of Mercury in China

Liu

Zhang

Luo

et al. 2018

Environ. Sci. Technol.

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Terrestrial mercury (Hg) transport, induced by water erosion and exacerbated by human activities, constitutes a major disturbance of the natural Hg cycle, but the processes are still not well understood. In this study, we modeled these processes using detailed information on erosion and Hg in soils and found that vast quantities of total Hg (THg) are being removed from land surfaces in China as a result of water erosion, which were estimated at 420 Mg/yr around 2010. This was significantly higher than the 240 Mg/yr mobilized around 1990. The erosion mechanism excavated substantial soil THg, which contributed to enhanced Hg(0) emissions to the atmosphere (4.9 Mg/yr around 2010) and its transport horizontally into streams (310 Mg/yr). Erosion-induced THg transport was driven by the extent of precipitation but was further enhanced or reduced by vegetation cover and land use changes in some regions. Surface air temperature may exacerbate the horizontal THg release into water. Our analyses quantified the processes of erosion-induced THg transport in terrestrial ecosystems, demonstrated its importance, and discussed how this transport is impacted by anthropogenic inputs and legacy THg in soils. We suggest that policy makers should pay more attention to legacy anthropogenic THg sources buried in soil.

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“…A detailed description of the simulation processes has been reported in our previous studies (Hui et al, 2016;Wu et al, 2016;L. Zhang et al, 2015).…”

Section: Uncertainty Analysismentioning

confidence: 99%

“…Thus, these two processes are potentially important in shaping the trends in ISP Hg emissions. Later long-term emission inventories revised the unique emission factor with dynamic factors by adopting a transformed normal distribution function (Tian et al, 2015;Wu et al, 2016). Such a method was based on the assumption that the emission factor was gradually improved according to the simulation curve and attempted to simulate the impact of technology improvement and pollution control on emission factor variation.…”

Section: Introductionmentioning

confidence: 99%

Updated atmospheric speciated mercury emissions from iron and steel production in China during 2000–2015

Gao

Hao

2017

Atmos. Chem. Phys.

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Abstract. Iron and steel production (ISP) is one of the significant atmospheric Hg emission sources in China. Atmospheric mercury (Hg) emissions from ISP during 2000-2015 were estimated by using a technology-based emission factor method. To support the application of this method, databases of Hg concentrations in raw materials, technology development trends, and Hg removal efficiencies of air pollution control devices (APCDs) were constructed through national sampling and literature review. Hg input to ISP increased from 21.6 t in 2000 to 94.5 t in 2015. In the various types of raw materials, coking coal and iron concentrates contributed 35-46 and 25-32 % of the total Hg input. Atmospheric Hg emissions from ISP increased from 11.5 t in 2000 to 32.7 t in 2015 with a peak of 35.6 t in 2013. Pollution control promoted the increase in average Hg removal efficiency, from 47 % in 2000 to 65 % in 2015. During the study period, sinter/pellet plants and blast furnaces were the largest two emission processes. However, emissions from roasting plants and coke ovens cannot be ignored, which accounted for 22-34 % of ISP's emissions. Overall, Hg speciation shifted from 50/44/6 (gaseous elemental Hg (Hg 0 )/gaseous oxidized Hg (Hg II )/particulate-bound Hg (Hg p )) in 2000 to 40/59/1 in 2015, which indicated a higher proportion of Hg deposition around the emission points. Future emissions of ISP were expected to decrease based on the comprehensive consideration crude-steel production, steel scrap utilization, energy saving, and pollution control measures.

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Temporal Trend and Spatial Distribution of Speciated Atmospheric Mercury Emissions in China During 1978–2014

Cited by 277 publications

References 27 publications

Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China

Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China

Impact of Water-Induced Soil Erosion on the Terrestrial Transport and Atmospheric Emission of Mercury in China

Updated atmospheric speciated mercury emissions from iron and steel production in China during 2000–2015

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