Magnification of atmospheric mercury deposition to polar regions in springtime: The link to tropospheric ozone depletion chemistry

Lu, Junjie; Schroeder, W. H.; Barrie, L. A.; Steffen, Alexandra; Welch, H. E.; Martin, Kathleen; Lockhart, Lyle; Hunt, R. V.; Boila, Gail; Richter, Andreas

doi:10.1029/2000gl012603

Cited by 262 publications

(303 citation statements)

References 15 publications

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“…When the concentration of GEM in ambient air decreased below 1.5 ng sm À3 , the GEM concentration in pyrolyzed air exceeded those measured in the ambient air indicating there are measurable quantities of other mercury species present, which can account for 50% or more of the depleted mercury. It is postulated that the remaining Hg (II) has been lost from the atmosphere by deposition to the snowpack [Lu et al, 2001;Steffen et al, 2002]. The similarity in GEM concentrations seen in Figure 9 at the surface at Alert and at altitudes up to 1 km, together with the vertical mixing suggested by the profiles of Figure 5b indicates that it is possible that 50% of the mercury depletion seen can be accounted for by Hg(II) present in the air but not detected.…”

Section: Processes Influencing the Concentration Of Gem In The Arcticmentioning

confidence: 58%

“…If the mixing of gaseous elemental mercury downwards is sufficient to permit 20 cycles of depletion of 0.6 mg m À2 over the full spring season, and 50% of this depleted GEM can be permanently lost to the atmosphere by deposition to the snowpack, the total loss would be 100 t. The total burden of GEM in the Northern Hemisphere (surface area of 205 million km 2 ) for a constant profile of 1.7 ng sm À3 up to 10 km is approximately 2000 t. A loss of 100 t would have the effect of reducing the concentration of gaseous mercury to 1.6 ng sm À3 throughout the Northern Hemisphere up to 10 km. From analysis of snow samples, Lu et al [2001] estimate that the total mass of Hg in the spring snowpack of Arctic seas and on Hudson Bay (an area of 10 6 km 2 ) is about 50 t. This latter value is one half the total deposition estimated above, occurring on one fifteenth of the area as estimated above, an indication that we have underestimated the overall amount of mercury deposited in the calculation. If this is true, then a sizeable fraction of the atmospheric mercury deposited must be re-emitted again as GEM in order to keep the hemispheric burden within the bounds observed.…”

Section: Significance Of the Gem Depletion Seen In The Arcticmentioning

confidence: 80%

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Vertical distribution of gaseous elemental mercury in Canada

Banic¹,

Beauchamp²,

Tordon³

et al. 2003

J. Geophys. Res.

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[1] Measurements of gaseous elemental mercury (GEM) were made in three locations in Canada at altitudes from 0.1 to 7 km. In the summer in southeastern Canada, northwesterly winds bring air with a constant mixing ratio of GEM at altitudes up to 7 km, with a concentration near 1.5 nanograms per standard cubic meter of air (ng sm À3 ). In the winter in southern and central Ontario the mixing ratio is still approximately constant with altitude, but the concentration is 1.7 ng sm À3 . In the spring in the Arctic the concentration of gaseous elemental mercury at altitudes above 1 km is near 1.7 ng sm À3 ; however, there is evidence of episodic depletion of elemental mercury near the surface with mixing of depleted air to altitudes of 1 km. Measurements of GEM in cloud interstitial air and of mercury in cloud water indicate that the influence of a single cycling of air through cloud has little effect on the concentration of GEM. The GEM in air masses transported over the relatively unpopulated terrain of northern Canada during the summer indicates a lower limit of 5000 ng m À2 for an atmospheric column from the surface to 5 km. This gives a global burden of at least 2500 t for that altitude range. These data demonstrate the existence of a vast pool of mercury aloft, provide evidence for a long atmospheric lifetime, and illustrate the potential for long-range atmospheric transport of this metal at altitudes up to at least 7 km.

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Section: Processes Influencing the Concentration Of Gem In The Arcticmentioning

confidence: 58%

Section: Significance Of the Gem Depletion Seen In The Arcticmentioning

confidence: 80%

Vertical distribution of gaseous elemental mercury in Canada

Banic¹,

Beauchamp²,

Tordon³

et al. 2003

J. Geophys. Res.

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“…Previous studies reported that the GEM concentration tends to decrease, while RGM or Hg p concentration is likely to increase, at elevated O 3 concentration (Selin et al, 2007;Sommar et al, 2010). It (Mason and Sheu, 1994;Schroeder and Munthe, 1998;Lin and Pehkonen, 1999;Lu et al, 2001;Mason and Sheu, 2002;Poissant et al, 2005;Feng and Qiu, 2008). However, if the aerosol particles contained high content of sea salts from oceanic spray, O 3 could be adsorbed onto the surface of these aerosol particles, and thus reducing the O 3 concentration, and more importantly, further oxidizing gaseous elemental mercury (GEM) to its oxidized forms (Hg + and Hg…”

Section: Correlation Of Tgm With Meteorological Parameters and Critermentioning

confidence: 99%

Field Measurement of Total Gaseous Mercury and Its Correlation with Meteorological Parameters and Criteria Air Pollutants at a Coastal Site of the Penghu Islands

Jen

Chen

Hung

et al. 2014

Aerosol Air Qual. Res.

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This study investigated the seasonal and daily variations of the total gaseous mercury (TGM) concentration in the ambient atmosphere, the correlation of TGM concentration with meteorological parameters (e.g., temperature, humidity, and wind speed) and criteria air pollutant concentrations (e.g., SO 2 , NO x , CO, O 3 , PM 10 , and PM 2.5 ), as well as the transportation routes, at the Penghu Islands. The field measurement results showed that the average TGM concentration during the monitoring period was 3.17 ± 1.17 ng/m 3 , within the range of 1.17-8.63 ng/m 3 , with the highest concentration being observed in spring, while the TGM concentration typically increased in the morning, reached its peak concentration, and then started to decrease at nightfall. Moreover, the lowest average TGM concentration of 1.81 ± 0.15 ng/m 3 was observed in summer, and this figure is close to the background TGM concentration of the Northern Hemisphere (1.6-1.8 ng/m 3 ). The correlation analysis indicated that TGM concentration correlated positively with SO 2 , NO x , CO, O 3 , PM 10 , PM 2.5 and negatively with ambient temperature, relative humidity, and wind speed. In addition, the transportation route analysis showed that elevated TGM concentrations could be transported from either North China, East China, or South China to the Penghu Islands, while those originating from the South China Sea had the lowest contribution to the TGM levels at the Penghu Islands. Therefore, local sources and open burning might be mainly influenced by the long-range transportation of air masses, as the prevailing wind direction and air mass transportation routes potentially play critical roles in the variation of TGM concentration at the Penghu Islands.

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“…54 g) The deposition rate of Hg may be enhanced by the presence of bromine species. 61 h) BrO may act as a sink for DMS in unpolluted marine environments.…”

Section: Experimental Evidencementioning

confidence: 99%