Atmospheric speciation of mercury in two contrasting Southeastern US airsheds

Gabriel, Mark; Williamson, Derek; Brooks, Steve; Lindberg, S. E.

doi:10.1016/j.atmosenv.2005.05.003

Cited by 86 publications

(53 citation statements)

References 43 publications

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“…Average GOM and PBM concentrations at Dartmouth were lower than many of the urban sites listed in Table 1 even after consideration of the 30-40 % uncertainties for GOM concentrations (Gustin and Jaffe, 2010). Previous studies conducted at urban sites have not only observed higher atmospheric Hg concentrations than those at rural sites, but also larger variability in the concentrations (Gabriel et al, 2005;Song et al, 2009;Liu et al, 2010). The overall variability in GEM concentrations based on relative standard deviation at Dartmouth was comparable to some of the major cities, such as Toronto, Windsor, Detroit, and Birmingham.…”

Section: Overall Concentrationsmentioning

confidence: 89%

“…Speciated atmospheric mercury concentrations have been measured at many urban locations across the United States, including Detroit (Liu et al, 2007(Liu et al, , 2010, Houston (Brooks et al, 2010), Tuscaloosa (Gabriel et al, 2005), Reno Peterson et al, 2009), Birmingham (Nair et al, 2012), Milwaukee (Rutter et al, 2007), and Rochester . In Canada, these measurements have taken place at two urban locations: Toronto and Windsor (Xu and Akhtar, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Concentration-weighted trajectory approach to identifying potential sources of speciated atmospheric mercury at an urban coastal site in Nova Scotia, Canada

Cheng¹,

et al. 2013

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Regional and local sources contributing to gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (PBM) at an urban coastal site in Dartmouth, Nova Scotia, Canada were investigated using the Concentration-Weighted Trajectory model (CWT) and Conditional Probability Function. From 2010–2011, GEM, GOM, and PBM concentrations were 1.67 ± 1.01 ng m⁻³, 2.07 ± 3.35 pg m⁻³, and 2.32 ± 3.09 pg m⁻³, respectively. Seasonal variability was observed, with statistically higher GEM and PBM concentrations in winter and spring and higher GOM in spring. In the CWT, concentrations are the weighting factors for the trajectory residence time in modeled grid cells, which results in the identification of source areas based on the CWT values in the grid cells. Potential source areas were identified in regions with known industrial Hg sources particularly in the fall season, but also in regions without these sources (e.g. Atlantic Ocean, northern Ontario and Quebec). CWTs for GOM and PBM that were associated with ≥ 5 kg industrial Hg emissions from 2010–2011 were statistically larger than those with zero Hg emissions, despite a lack of strong correlations. A large proportion of elevated CWTs (85–97%) was in regions with zero industrial Hg sources indicating the potential role of non-point sources, natural emissions, and residential-scale combustion. Analysis of wind data suggests that a commercial harbor and vehicular traffic were potential local sources. Evaluating modeled source areas against Hg emissions inventories was not an ideal method for assessing the CWT model accuracy because of insufficient data on Hg emissions at more precise locations

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Section: Overall Concentrationsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Concentration-weighted trajectory approach to identifying potential sources of speciated atmospheric mercury at an urban coastal site in Nova Scotia, Canada

Cheng¹,

et al. 2013

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“…Some studies often found association between high concentrations of mercury and wind direction which points to upwind source regions (e.g., Gabriel et al, 2005;Poissant et al, 2005;Aucott et al, 2009;Sigler et al, 2009a;Baya and van Heyst, 2010), while others detected no correlation (Castillo et al, 2011). In addition, our previous study found a relationship between wind speed and possible oceanic evasion (Sigler et al, 2009b).…”

Section: H Mao Et Al: Speciated Mercury At Marine Coastal and Inlmentioning

confidence: 93%

Speciated mercury at marine, coastal, and inland sites in New England – Part 2: Relationships with atmospheric physical parameters

et al. 2012

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Abstract. Long-term continuous measurements of gaseous elemental mercury (Hg 0 ), reactive gaseous mercury (RGM), and particulate phase mercury (Hg P ) were conducted at coastal (Thompson Farm, denoted as TF), marine (Appledore Island, denoted as AI), and elevated inland rural (Pac Monadnock, denoted as PM) monitoring sites of the AIRMAP Observing Network. Diurnal, seasonal, annual, and interannual variability in Hg 0 , RGM, and Hg P from the three distinctly different environments were characterized and compared in Part 1. Here in Part 2 relationships between speciated mercury (i.e., Hg 0 , RGM, and Hg P ) and climate variables (e.g., temperature, wind speed, humidity, solar radiation, and precipitation) were examined. The best point-to-point correlations were found between Hg 0 and temperature in summer at TF and spring at PM, but there was no similar correlation at AI. Subsets of data demonstrated regional impacts of episodic dynamic processes such as strong cyclonic systems on ambient levels of Hg 0 at all three sites, possibly through enhanced oceanic evasion of Hg 0 . A tendency of higher levels of RGM and Hg P was identified in spring and summer under sunny conditions in all environments. Specifically, the 10th, 25th, median, 75th, and 90th percentile mixing ratios of RGM and Hg P increased with stronger solar radiation at both the coastal and marine sites. These metrics decreased with increasing wind speed at AI indicating enhanced loss of RGM and Hg P through deposition. RGM and Hg P levels correlated with temperature positively in spring, summer and fall at the coastal and marine locations. At the coastal site relationships between RGM and relative humidity suggested a clear decreasing tendency in all metrics from <40 % to 100 % relative humidity in all seasons especially in spring, compared to less variability in the marine environment. The effect of precipitation on RGM at coastal and marine locations was similar. At the coastal site, RGM levels were a factor of 3-4 to two orders of magnitude higher under dry conditions than rainy conditions in all seasons. In winter RGM mixing ratios appeared to be mostly above the limit of detection (LOD) during snowfalls suggesting less scavenging efficiency of snow. Mixing ratios of Hg P at the coastal and marine sites remained above the LOD under rainy conditions. Precipitation had negligible impact on the magnitude and pattern of diurnal variation of Hg P in all seasons in the marine environment.

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“…When reported on an hourly basis, urban Hg levels can be significantly higher than the longer term averages noted above. 28 For example, if hourly urban Hg mixing ratios were occasionally 5 times higher than the long-term average (i.e., 20 ng/m 3 or ϳ2.4 ppt) the estimated interference toward O 3 monitored by a UV O 3 analyzer would be 2-3 ppb. More substantial Hg interference may be encountered near Hg sources 10 or perhaps during wildfire plume events.…”

Section: Effect Of Selected Chemicals On Omentioning

confidence: 99%