scholarly journals Mercury deposition in Southern New Hampshire, 2006–2009

2011 ◽  
Vol 11 (15) ◽  
pp. 7657-7668 ◽  
Author(s):  
M. A. S. Lombard ◽  
J. G. Bryce ◽  
H. Mao ◽  
R. Talbot
Keyword(s):  
New Hampshire ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Winter Precipitation ◽  
Rural Site ◽  
Mercury Deposition ◽  
Mixing Ratios ◽  
Order Of Magnitude ◽  
Aqueous Mercury ◽  
Event Based

Abstract. The atmospheric deposition of mercury (Hg) occurs via several mechanisms including wet, dry, and occult processes. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, event-based wet deposition samples and reactive gaseous Hg (RGM) measurements were collected for approximately 3 years at Thompson Farm (TF), a near-coastal rural site in Durham, NH, part of the University of New Hampshire AIRMAP Observing Network. Total aqueous mercury exhibited seasonal patterns in Hg wet deposition at TF. The lowest Hg wet deposition was measured in the winter with an average total seasonal deposition of 1.56 μg m−2 compared to the summer average of 4.71 μg m−2. Inter-annual differences in total wet deposition are generally linked with precipitation volume, with the greatest deposition occurring in the wettest year. Relationships between surface level RGM and Hg wet deposition were also investigated based on continuous RGM measurements at TF from November 2006 to September 2009. No correlations were observed between RGM mixing ratios and Hg wet deposition, however the ineffective scavenging of RGM during winter precipitation events was evidenced by the less frequent depletion of RGM below the detection level. Seasonal dry deposition of reactive gaseous Hg (RGM) was estimated using an order-of-magnitude approach. RGM mixing ratios and dry deposition estimates were greatest during the winter and spring. The seasonal ratios of Hg wet deposition to RGM dry deposition vary by up to a factor of 80.

scholarly journals Mercury deposition in southern New Hampshire, 2006–2009

2011 ◽  
Vol 11 (2) ◽  
pp. 4569-4598
Author(s):  
M. A. S. Lombard ◽  
J. G. Bryce ◽  
H. Mao ◽  
R. Talbot
Keyword(s):  
New Hampshire ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Meteorological Data ◽  
Primary Source ◽  
Rural Site ◽  
Mercury Deposition ◽  
Mixing Ratios ◽  
Order Of Magnitude ◽  
Aqueous Mercury

Abstract. Mercury (Hg) is a global contaminant due to its toxicity and ubiquitous presence in the atmosphere. The primary source of Hg to terrestrial and aquatic ecosystems is atmospheric deposition. In an effort to understand the atmospheric cycling and depositional characteristics of Hg, event-based wet deposition samples were collected from July 2006 to September 2009 at Thompson Farm (TF), a near-coastal rural site in Durham, NH, part of the University of New Hampshire AIRMAP Observing Network. Total aqueous mercury exhibited seasonal trends in Hg wet deposition at TF. The lowest Hg wet deposition occurred in the winter with an average total seasonal deposition of 1.56 μg m−2 compared to the summer average of 4.71 μg m−2. Inter-annual differences are generally linked with precipitation volume, with the greatest deposition occurring in the wettest year. Comparisons of Hg wet deposition trends with meteorological data and ambient gas phase mixing ratios revealed weak correlations. The strongest correlation was observed between maximum hourly precipitation rate and Hg wet deposition, and the relationship was strongly driven by extreme events. Dry deposition of reactive gaseous Hg (RGM) was estimated based on continuous RGM measurements at TF from October 2006 to September 2009 using an order-of-magnitude approach. Comparisons between Hg wet deposition and RGM dry deposition suggest that the seasonal ratios of Hg wet deposition to RGM dry deposition vary by up to a factor of 80. Additional studies of seasonal differences in Hg deposition mechanisms (wet vs. dry) may provide a better understanding of the biogeochemical cycling of Hg.

scholarly journals Triple oxygen isotopes indicate urbanization affects sources of nitrate in wet and dry atmospheric deposition

2018 ◽  
Author(s):  
David M. Nelson ◽  
Urumu Tsunogai ◽  
Ding Dong ◽  
Takuya Ohyama ◽  
Daisuke D. Komatsu ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Urban Environments ◽  
Rural Site ◽  
Urban Site ◽  
Peroxy Radicals ◽  
Long Distance ◽  
Wet And Dry Deposition ◽  
Atmospheric Nitrate ◽  
Nitrate Deposition

Abstract. Atmospheric nitrate deposition resulting from anthropogenic activities negatively affects human and environmental health. Identifying deposited nitrate that is produced locally vs. that originating from long-distance transport would help inform efforts to mitigate such impacts. However, distinguishing the relative transport distances of atmospheric nitrate in urban areas remains a major challenge since it may be produced locally and/or come from upwind regions. To address this uncertainty we assessed spatiotemporal variation in monthly weighted-average Δ17O and δ15N values of wet and dry nitrate deposition during one year at urban and rural sites along the western coast of the northern Japanese island of Hokkaido, downwind of the East Asian continent. Δ17O values of nitrate in wet deposition at the urban site mirrored those of wet and dry deposition at the rural site, ranging between ~ +22 and +30 ‰ with higher values during winter and lower values in summer, which suggests greater relative importance of oxidation of NO2 by O3 during winter and OH during summer. In contrast, Δ17O values of nitrate in dry deposition at the urban site were lower (+19–+25 ‰) and displayed less distinct seasonal variation. Furthermore, the difference between δ15N values of nitrate in wet and dry nitrate deposition was, on average, 3 ‰ greater at the urban than rural site, and Δ17O and δ15N values were correlated for both forms of deposition at both sites with the exception of dry deposition at the urban site. These results suggest that, relative to nitrate in wet deposition in urban environments and wet and dry deposition in rural environments, nitrate in dry deposition in urban environments forms from relatively greater oxidation of NO by peroxy radicals and/or oxidation of NO2 by OH. Given greater concentrations of peroxy radicals and OH in cities, these results imply that dry nitrate deposition results from local NOx emissions more so than wet deposition, which is transported longer distances. These results illustrate the value of stable isotope data for distinguishing the transport distances and reaction pathways of atmospheric nitrate pollution.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2014 ◽  
Vol 14 (5) ◽  
pp. 2233-2244 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractionated particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume-weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban North America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, as well as nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium, and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of the HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer, while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal, with two peaks in the bins of < 0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Temporal variability, sources, and sinks of C<sub>1</sub>-C<sub>5</sub> alkyl nitrates in Coastal New England

2009 ◽  
Vol 9 (6) ◽  
pp. 23371-23418 ◽  
Author(s):  
R. S. Russo ◽  
Y. Zhou ◽  
K. B. Haase ◽  
O. W. Wingenter ◽  
E. K. Frinak ◽  
...  
Keyword(s):  
New England ◽  
New Hampshire ◽  
Dry Deposition ◽  
Ambient Air ◽  
Early Morning ◽  
Secondary Source ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Alkyl Nitrate ◽  
Marine Source

Abstract. Seven C1-C5 alkyl nitrates were measured both on the mainland and off the coast of New Hampshire using gas chromatographic techniques. Five separate data sets will be presented to characterize the seasonal and diurnal trends and the major sources and loss processes of these compounds. In situ measurements were conducted at the University of New Hampshire (UNH) Atmospheric Observing Station at Thompson Farm (TF) located in southeast NH during winter (January–February) and summer (June–August) 2002 and summer (July–August) 2004. The median (±standard deviation) total alkyl nitrate mixing ratio (ΣRONO2) was 25 (±7) in winter and 16 (±14) pptv in summer. Furthermore, daily canister samples collected at midday and later analyzed in the laboratory from January 2004–February 2008 gave median ΣRONO2 of 23 (±8) in winter and 14 (±10) pptv in summer. Alkyl nitrate mixing ratios increased throughout the morning and were highest in the afternoon reflecting mixing of remnant boundary layer air toward the surface and photochemical production during the day. During summers 2002 and 2004, MeONO2 decreased overnight and reached minimum hourly average mixing ratios in the early morning (05:00–07:00 LT). Comparison with wind speed and trace gas (i.e., hydrocarbons, ozone, carbon monoxide, total reactive nitrogen) trends suggested that dry deposition contributed to the early morning MeONO2 minimum which is a previously unaccounted for removal mechanism. The mean dry deposition rate and velocity of MeONO2 was estimated to be −0.5 nmol m−2 hr−1 and 0.13 cm s−1, respectively. Results from ambient air and surface seawater measurements made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England Air Quality Study and from ambient canister samples collected throughout the Great Bay estuary in August 2003 are also presented. Comparisons between the alkyl nitrate trends with anthropogenic and marine source fingerprints and tracers suggest that a marine source of alkyl nitrates is not significant in coastal New England. Given the apparent prominence of a secondary source, comparisons between observed and predicted alkyl nitrate/parent hydrocarbon ratios were made which demonstrated that background mixing ratios have a continuous and prevalent influence on the alkyl nitrate distribution.

scholarly journals Atmospheric mercury deposition over the land surfaces and the associated uncertainties in observations and simulations: a critical review

2019 ◽  
Vol 19 (24) ◽  
pp. 15587-15608 ◽  
Author(s):  
Lei Zhang ◽  
Peisheng Zhou ◽  
Shuzhen Cao ◽  
Yu Zhao
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Quantitative Methods ◽  
Experimental System ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Future Research ◽  
Observation Data ◽  
Mercury Deposition ◽  
Land Surfaces

Abstract. One of the most important processes in the global mercury (Hg) biogeochemical cycling is the deposition of atmospheric Hg, including gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM), to the land surfaces. Results of wet, dry, and forest Hg deposition from global observation networks, individual monitoring studies, and observation-based simulations have been reviewed in this study. Uncertainties in the observation and simulation of global speciated atmospheric Hg deposition to the land surfaces have been systemically estimated based on assessment of commonly used observation methods, campaign results for comparison of different methods, model evaluation with observation data, and sensitivity analysis for model parameterization. The uncertainties of GOM and PBM dry deposition measurements come from the interference of unwanted Hg forms or incomplete capture of targeted Hg forms, while that of GEM dry deposition observation originates from the lack of a standardized experimental system and operating procedure. The large biases in the measurements of GOM and PBM concentrations and the high sensitivities of key parameters in resistance models lead to high uncertainties in GOM and PBM dry deposition simulation. Non-precipitation Hg wet deposition could play a crucial role in alpine and coastal regions, and its high uncertainties in both observation and simulation affect the overall uncertainties of Hg wet deposition. The overall uncertainties in the observation and simulation of the total global Hg deposition were estimated to be ± (25–50) % and ± (45–70) %, respectively, with the largest contributions from dry deposition. According to the results from uncertainty analysis, future research needs were recommended, among which a global Hg dry deposition network, unified methods for GOM and PBM dry deposition measurements, quantitative methods for GOM speciation, campaigns for comprehensive forest Hg behavior, and more efforts in long-term Hg deposition monitoring in Asia are the top priorities.

scholarly journals Temporal variability, sources, and sinks of C<sub>1</sub>-C<sub>5</sub> alkyl nitrates in coastal New England

2010 ◽  
Vol 10 (4) ◽  
pp. 1865-1883 ◽  
Author(s):  
R. S. Russo ◽  
Y. Zhou ◽  
K. B. Haase ◽  
O. W. Wingenter ◽  
E. K. Frinak ◽  
...  
Keyword(s):  
New England ◽  
New Hampshire ◽  
Dry Deposition ◽  
Gulf Of Maine ◽  
Ambient Air ◽  
Early Morning ◽  
Secondary Source ◽  
Alkyl Nitrates ◽  
Mixing Ratios ◽  
Alkyl Nitrate

Abstract. Seven C1-C5 alkyl nitrates were measured both on the mainland and off the coast of New Hampshire using gas chromatographic techniques. Five separate data sets are presented to characterize the seasonal and diurnal trends and the major sources and loss processes of these compounds. Based on in situ measurements conducted at the University of New Hampshire (UNH) Atmospheric Observing Station at Thompson Farm (TF) located in southeast NH during winter (January–February) 2002, summer (June–August) 2002, summer (July–August) 2004, and on daily canister samples collected at midday from January 2004–February 2008, the median total alkyl nitrate mixing ratio (ΣRONO2) was 23–25 pptv in winter and 14–16 pptv in summer. During summers 2002 and 2004, MeONO2 decreased overnight and reached minimum hourly average mixing ratios in the early morning. Comparison with wind speed and trace gas trends suggested that dry deposition contributed to the early morning MeONO2 minimum which is a previously unaccounted for removal mechanism. The mean dry deposition rate and velocity of MeONO2 was estimated to be −0.5 nmol m−2 hr−1 and 0.13 cm s−1, respectively. Results from ambient air and surface seawater measurements made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England Air Quality Study and from ambient canister samples collected throughout the Great Bay estuary in August 2003 are also presented. Comparisons between the alkyl nitrate trends with anthropogenic and marine tracers suggest that a marine source of alkyl nitrates is not significant in coastal New England. Given the apparent prominence of a secondary source, comparisons between observed and predicted alkyl nitrate/parent hydrocarbon ratios were made which demonstrated that background mixing ratios have a continuous and prevalent influence on the alkyl nitrate distribution.

scholarly journals Direct Measurement of Mercury Deposition at Rural and Suburban Sites in Washington State, USA

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Marc W. Beutel ◽  
Lanka DeSilva ◽  
Louis Amegbletor
Keyword(s):  
Direct Measurement ◽  
Dry Deposition ◽  
Low Cost ◽  
Deposition Velocity ◽  
Washington State ◽  
Rural Site ◽  
Storm Events ◽  
Mercury Deposition ◽  
Spatial And Temporal Patterns ◽  
Atmospheric Concentration

Because of mercury’s (Hg) capacity for long-range transport in the atmosphere, and its tendency to bioaccumulate in aquatic biota, there is a critical need to measure spatial and temporal patterns of Hg atmospheric deposition. Dry deposition of Hg is commonly calculated as the product of a measured atmospheric concentration and an assumed deposition velocity. An alternative is to directly assess Hg deposition via accumulation on surrogate surfaces. Using a direct measurement approach, this study quantified Hg deposition at a rural site (Pullman) and suburban site (Puyallup) in Washington State using simple, low-cost equipment. Dry deposition was measured using an aerodynamic “wet sampler” consisting of a Teflon plate, 35 cm in diameter, holding a thin layer (2.5 mm) of recirculating acidic aqueous receiving solution. In addition, wet Hg deposition was measured using a borosilicate glass funnel with a 20-cm-diameter opening and a 1 L Teflon sampling bottle. Hg deposition was estimated based on changes in total Hg in the aqueous phase of the samplers. Dry Hg deposition was 2.4 ± 1.4 ng/m2·h (average plus/minus standard deviation; n = 4) in Pullman and 1.3 ± 0.3 ng/m2·h (n = 6) in Puyallup. Wet Hg deposition was 7.0 ± 4.8 ng/m2·h (n = 4) in Pullman and 1.1 ± 0.2 ng/m2·h (n = 3) in Puyallup. Relatively high rates of Hg deposition in Pullman were attributed to regional agricultural activities that enhance mercury re-emission and deposition including agricultural harvesting and field burning. Hg concentration in precipitation negatively correlated with precipitation depth, indicating that Hg was scavenged from the atmosphere during the beginning of storm events. Because of their relative simplicity and robustness, direct measurement approaches such as those described in this study are useful in assessing Hg deposition, and for comparing results to less direct estimates and model estimates of Hg deposition.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2013 ◽  
Vol 13 (11) ◽  
pp. 28309-28341 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractioned particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, and nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal with two peaks in the bins of <0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Oceanic influence on atmospheric mercury at coastal and inland sites: a springtime noreaster in New England

2009 ◽  
Vol 9 (2) ◽  
pp. 8737-8755
Author(s):  
J. M. Sigler ◽  
H. Mao ◽  
B. C. Sive ◽  
R. Talbot
Keyword(s):  
New England ◽  
New Hampshire ◽  
Magnitude Estimate ◽  
High Elevation ◽  
Atmospheric Mercury ◽  
Mixing Ratios ◽  
Marine Source ◽  
Order Of Magnitude ◽  
Near Shore ◽  
The Impact

Abstract. Continuous measurements of elemental (Hg0) and reactive mercury were conducted at two sites in New Hampshire during a powerful April 2007 noreaster. During the most intense period of the storm, enhancements of ~30–50 ppqv in Hg0 were observed at a coastal and a high elevation inland site. This enhancement occurred simultaneously with elevated mixing ratios of three marine tracers, CH3I, CH2Br2 and CHBr3. These observations suggest a marine source of Hg0, possibly outgassing from the ocean surface during strong turbulence. The Hg0 enhancement observed 100 km inland suggests that the impact of coastal storms on terrestrial Hg cycling may not be limited to near-shore environments. Combining Hg0 and marine tracer measurements during the storm with estimates of oceanic tracer fluxes during previous strong storms yields an order-of-magnitude estimate of the oceanic source of Hg0 during the storm (~7 ppqv hr

scholarly journals Total atmospheric mercury deposition in forested areas in South Korea

2016 ◽  
Vol 16 (12) ◽  
pp. 7653-7662 ◽  
Author(s):  
Jin-Su Han ◽  
Yong-Seok Seo ◽  
Moon-Kyung Kim ◽  
Thomas M. Holsen ◽  
Seung-Muk Yi
Keyword(s):  
South Korea ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Deciduous Forest ◽  
Atmospheric Mercury ◽  
Deposition Flux ◽  
Mercury Deposition ◽  
Temperate Deciduous Forest ◽  
Deposition Fluxes ◽  
Forested Areas

Abstract. In this study, mercury (Hg) was sampled weekly in dry and wet deposition and throughfall and monthly in litterfall, and as it was volatilized from soil from August 2008 to February 2010 to identify the factors influencing the amount of atmospheric Hg deposited to forested areas in a temperate deciduous forest in South Korea. For this location there was no significant correlation between the estimated monthly dry deposition flux (litterfall + throughfall – wet deposition) (6.7 µg m−2 yr−1) and directly measured dry deposition (9.9 µg m−2 yr−1) likely due primarily to Hg losses from the litterfall collector. Dry deposition fluxes in cold seasons (fall and winter) were lower than in warmer seasons (spring and summer). The volume-weighted mean (VWM) Hg concentrations in both precipitation and throughfall were highest in winter, likely due to increased scavenging by snow events. Since South Korea experiences abundant rainfall in summer, VWM Hg concentrations in summer were lower than in other seasons. Litterfall fluxes were highest in the late fall to early winter, when leaves were dropped from the trees (September to November). The cumulative annual Hg emission flux from soil was 6.8 µg m−2 yr−1. Based on these data, the yearly deposition fluxes of Hg calculated using two input approaches (wet deposition + dry deposition or throughfall + litterfall) were 6.8 and 3.6 µg m−2 yr−1, respectively. This is the first reported study which measured the amount of atmospheric Hg deposited to forested areas in South Korea, and thus our results provide useful information to compare against data related to Hg fate and transport in this part of the world.

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