scholarly journals Odds and ends of atmospheric mercury in Europe and over northern Atlantic Ocean: Temporal trends of 25 years of measurements

2021 ◽  
Author(s):  
Danilo Custódio ◽  
Franz Slemr ◽  
Katrine Aspmo Pfaffhuber ◽  
T. Gerard Spain ◽  
Fidel F. Pankratov ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Mass Function ◽  
Global Scale ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Back Trajectories ◽  
Air Masses ◽  
Minamata Convention On Mercury ◽  
Northern Atlantic ◽  
Concentration Weighted Trajectories

Abstract. The Global Monitoring Plan of the Minamata Convention on Mercury was established to generate long-term data necessary for evaluating the effectiveness of regulatory measures at a global scale. After 25 years monitoring (since 1995), Mace Head is one of the atmospheric monitoring stations with the longest mercury record, and has produced sufficient data for the analysis of temporal trends of Total Gaseous Mercury (TGM) in Europe and the Northern Atlantic. Using concentration-weighted trajectories for atmospheric mercury measured at Mace Head as well as other five locations in Europe, Amderma, Andøya, Villum, Waldhof and Zeppelin we identify the regional probabilistic source contribution factor and its changes for the period of 1996 to 2019. Temporal trends indicate that concentrations of mercury in the atmosphere in Europe and the Northern Atlantic have declined significantly over the past 25 years, at a non-monotonic rate averaging of 0.03 ng m-3 year-1. Concentrations of TGM at remote marine sites were shown to be affected by continental long-range transport, and evaluation of reanalysis back-trajectories display a significant decrease of TGM in continental air masses from Europe in the last two decades. In addition, using the relationship between mercury and other atmospheric trace gases that could serve as a source signature, we perform factorization regression analysis, based on positive rotatable factorization of non-singular matrix to solve probabilistic mass function. We reconstructed atmospheric mercury concentration and accessed the contribution of the major natural and anthropogenic sources. The positive matrix factorization (PMF) reveals that the downward trend is mainly associated with a factor with a high load of long-lived anthropogenic species.

scholarly journals Atmospheric Mercury Concentrations observed at ground-based monitoring sites globally distributed in the framework of the GMOS network

2016 ◽  
Author(s):  
Francesca Sprovieri ◽  
Nicola Pirrone ◽  
Mariantonia Bencardino ◽  
Francesco D’Amore ◽  
Francesco Carbone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Ad Hoc ◽  
Temporal Trends ◽  
Global Scale ◽  
Atmospheric Mercury ◽  
Global Network ◽  
Observation System ◽  
Large Network ◽  
Deposition Processes ◽  
The Impact

Abstract. Long-term monitoring data of ambient mercury (Hg) on a global scale to assess its emission, transport, atmospheric chemistry, and deposition processes is vital to understanding the impact of Hg pollution on the environment. The Global Mercury Observation System (GMOS) project was funded by the European Commission (www.gmos.eu), and started in November 2010 with the overall goal to develop a coordinated global observing system to monitor Hg on a global scale, including a large network of ground-based monitoring stations, ad-hoc periodic oceanographic cruises and measurement flights in the lower and upper troposphere, as well as in the lower stratosphere. To date more than 40 ground-based monitoring sites constitute the global network covering many regions where little to no observational data were available before GMOS. This work presents atmospheric Hg concentrations recorded worldwide in the framework of the GMOS project (2010–2015), analyzing Hg measurement results in terms of temporal trends, seasonality and comparability within the network. Major findings highlighted in this paper include a clear gradient of Hg concentrations between the Northern and Southern Hemisphere, confirming that the gradient observed is mostly driven by local and regional sources, which can be anthropogenic, natural or a combination of both.

scholarly journals Aerosol Characteristics in the Three Poles of the Earth Observed by CALIPSO

2020 ◽  
Author(s):  
Yikun Yang ◽  
Chuanfeng Zhao ◽  
Quan Wang ◽  
Zhiyuan Cong ◽  
Xingchuan Yang ◽  
...  
Keyword(s):  
South Asia ◽  
Ross Sea ◽  
Temporal Trends ◽  
Arctic Region ◽  
The Arctic ◽  
Hysplit Model ◽  
Back Trajectories ◽  
Air Masses ◽  
Spatial And Seasonal Variation ◽  
The Antarctic

Abstract. To better understand the aerosol properties over the Arctic, Antarctic, and Tibetan Plateau (TP), the aerosol optical properties were investigated using 13 years CALIPSO L3 data, and the back trajectories for air masses were also simulated using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results show that the aerosol optical depth (AOD) has obvious spatial and seasonal variation characteristics, and the aerosol loading over Eurasia, Ross Sea, and South Asia is relatively large. The annual average AOD in the Arctic, Antarctic, and TP are 0.046, 0.025, and 0.098, respectively. The Arctic and Antarctic regions have larger AOD values in winter and spring, while the TP in spring and summer. There are no significant temporal trends of AOD anomalies in the three study regions. Clean marine and dust-related aerosols are the dominant types over ocean and land respectively in both the Arctic and Antarctic, while dust-related aerosol types have greater occurrence frequency (OF) over the TP. The OF of dust-related and elevated smoke is large for a broad range of heights, indicating that they are likely transported aerosols, while other types of aerosols mainly occurred at heights below 2 km in the Antarctic and Arctic. The maximum OF of dust-related aerosols mainly occurs at 6 km altitude over the TP. The analysis of back trajectories of the air masses shows large differences among different regions and seasons. The Arctic region is more vulnerable to mid-latitude pollutants than the Antarctic region, especially in winter and spring, while the air masses in the TP are mainly from the Iranian Plateau, Tarim Basin, and South Asia.

scholarly journals Atmospheric mercury in the Southern Hemisphere – Part 2: Source apportionment analysis at Cape Point station, South Africa

2020 ◽  
Author(s):  
Johannes Bieser ◽  
Hélène Angot ◽  
Franz Slemr ◽  
Lynwill Martin
Keyword(s):  
South Africa ◽  
Southern Hemisphere ◽  
Source Region ◽  
Global Scale ◽  
Atmospheric Mercury ◽  
Air Masses ◽  
Sources And Sinks ◽  
Relative Contribution ◽  
Range Transport ◽  
Significant Step

Abstract. Mercury (Hg) contamination is ubiquitous. In order to assess its emissions, transport, atmospheric reactivity, and deposition pathways, Hg monitoring stations have been implemented on a global scale over the past 10–20 years. Despite this significant step forward, the monitoring efforts have been insufficient to fulfill our understanding of Hg cycling in the Southern Hemisphere. While oceans make up 80 % of the Southern Hemisphere's surface area, little is known about the effects of oceans on Hg cycling in this region. For instance, in the context of growing interest in effectiveness evaluation of Hg mitigation policies, the relative contribution of anthropogenic and legacy emissions to present-day atmospheric Hg levels is unclear. This paper constitutes Part 2 of the study describing a decade of atmospheric Hg concentrations at Cape Point, South Africa, i.e. the first long-term (> 10 years) observations in the Southern Hemisphere. Building on the trend analysis reported in Part 1, here we combine atmospheric Hg data with a trajectory model to investigate sources and sinks of Hg at Cape Point. We find that the continent is the major sink and the Ocean, especially warm regions, is the major source for Hg. Further, we find that mercury concentrations and trends from long range transport are independent of the source region (e.g. South America, Antarctica) and thus indistinguishable. Therefor, by filtering out air masses from source and sink regions we are able to create a dataset representing a southern hemispheric background Hg concentrations. Based on this dataset we were able to show that the inter-annual variability of Hg concentrations is not driven by changes in atmospheric circulation but rather due to changes in global emissions (gold mining and biomass burning).

scholarly journals Origin of oxidized mercury in the summertime free troposphere over the southeastern US

2016 ◽  
Vol 16 (3) ◽  
pp. 1511-1530 ◽  
Author(s):  
V. Shah ◽  
L. Jaeglé ◽  
L. E. Gratz ◽  
J. L. Ambrose ◽  
D. A. Jaffe ◽  
...  
Keyword(s):  
Detection Limit ◽  
Transport Model ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Free Troposphere ◽  
Chemical Transport Model ◽  
Back Trajectories ◽  
Air Masses ◽  
The North ◽  
Southeastern Us

Abstract. We collected mercury observations as part of the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign over the southeastern US between 1 June and 15 July 2013. We use the GEOS-Chem chemical transport model to interpret these observations and place new constraints on bromine radical initiated mercury oxidation chemistry in the free troposphere. We find that the model reproduces the observed mean concentration of total atmospheric mercury (THg) (observations: 1.49 ± 0.16 ng m−3, model: 1.51 ± 0.08 ng m−3), as well as the vertical profile of THg. The majority (65 %) of observations of oxidized mercury (Hg(II)) were below the instrument's detection limit (detection limit per flight: 58–228 pg m−3), consistent with model-calculated Hg(II) concentrations of 0–196 pg m−3. However, for observations above the detection limit we find that modeled Hg(II) concentrations are a factor of 3 too low (observations: 212 ± 112 pg m−3, model: 67 ± 44 pg m−3). The highest Hg(II) concentrations, 300–680 pg m−3, were observed in dry (RH  <  35 %) and clean air masses during two flights over Texas at 5–7 km altitude and off the North Carolina coast at 1–3 km. The GEOS-Chem model, back trajectories and observed chemical tracers for these air masses indicate subsidence and transport from the upper and middle troposphere of the subtropical anticyclones, where fast oxidation of elemental mercury (Hg(0)) to Hg(II) and lack of Hg(II) removal lead to efficient accumulation of Hg(II). We hypothesize that the most likely explanation for the model bias is a systematic underestimate of the Hg(0) + Br reaction rate. We find that sensitivity simulations with tripled bromine radical concentrations or a faster oxidation rate constant for Hg(0) + Br, result in 1.5–2 times higher modeled Hg(II) concentrations and improved agreement with the observations. The modeled tropospheric lifetime of Hg(0) against oxidation to Hg(II) decreases from 5 months in the base simulation to 2.8–1.2 months in our sensitivity simulations. In order to maintain the modeled global burden of THg, we need to increase the in-cloud reduction of Hg(II), thus leading to faster chemical cycling between Hg(0) and Hg(II). Observations and model results for the NOMADSS campaign suggest that the subtropical anticyclones are significant global sources of Hg(II).

scholarly journals Aerosol characteristics at the three poles of the Earth as characterized by Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations

2021 ◽  
Vol 21 (6) ◽  
pp. 4849-4868
Author(s):  
Yikun Yang ◽  
Chuanfeng Zhao ◽  
Quan Wang ◽  
Zhiyuan Cong ◽  
Xingchuan Yang ◽  
...  
Keyword(s):  
South Asia ◽  
Ross Sea ◽  
Temporal Trends ◽  
Satellite Observations ◽  
The Arctic ◽  
Hysplit Model ◽  
Back Trajectories ◽  
Air Masses ◽  
Spatial And Seasonal Variation ◽  
The Antarctic

Abstract. To better understand the aerosol properties over the Arctic, Antarctic and Tibetan Plateau (TP), the aerosol optical properties were investigated using 13 years of CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations) L3 data, and the back trajectories for air masses were also simulated using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results show that the aerosol optical depth (AOD) has obvious spatial- and seasonal-variation characteristics, and the aerosol loading over Eurasia, Ross Sea and South Asia is relatively large. The annual-average AODs over the Arctic, Antarctic and TP are 0.046, 0.024 and 0.098, respectively. Seasonally, the AOD values are larger from late autumn to early spring in the Arctic, in winter and spring in the Antarctic, and in spring and summer over the TP. There are no significant temporal trends of AOD anomalies in the three study regions. Clean marine and dust-related aerosols are the dominant types over ocean and land, respectively, in both the Arctic and Antarctic, while dust-related aerosol types have greater occurrence frequency (OF) over the TP. The OF of dust-related and elevated smoke is large for a broad range of heights, indicating that they are likely transported aerosols, while other types of aerosols mainly occurred at heights below 2 km in the Antarctic and Arctic. The maximum OF of dust-related aerosols mainly occurs at 6 km altitude over the TP. The analysis of back trajectories of the air masses shows large differences among different regions and seasons. The Arctic region is more vulnerable to mid-latitude pollutants than the Antarctic region, especially in winter and spring, while the air masses in the TP are mainly from the Iranian Plateau, Tarim Basin and South Asia.

scholarly journals Ship Based Measurements of Seasonal Atmospheric Mercury Concentrations over the Baltic Sea

2017 ◽  
Author(s):  
Hanna Hoeglind ◽  
Sofia Eriksson ◽  
Katarina Gardfeldt
Keyword(s):  
Baltic Sea ◽  
Background Level ◽  
Ambient Air ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
The Baltic Sea ◽  
Back Trajectories ◽  
Gaseous Mercury ◽  
The Baltic

Mercury is a toxic pollutant emitted from both natural sources and through human activities. A global interest in atmospheric mercury has risen ever since the discovery of the Minamata disease in 1956. Properties of gaseous elemental mercury enable long range transport which can cause pollution even in pristine environments. Total gaseous mercury (TGM) was measured from winter 2016 to spring 2017 over the Baltic Sea. A Tekran 2357A mercury analyser was installed aboard the research and icebreaking vessel Oden for the purpose of continuous measurements of gaseous mercury in ambient air. Measurements were performed during a campaign along the Swedish east coast and in the Bothnian Bay near Lulea during the icebreaking season. Data was evaluated from Gothenburg using a plotting software and back trajectories for air masses were calculated. The TGM average of 1.365 &plusmn; 0.054 ng/m3 during winter and 1.288 &plusmn; 0.140 ng/m3 during spring was calculated as well as a total average of 1.362 &plusmn; 0.158 ng/m3. Back trajectories showed a possible correlation of anthropogenic sources elevating the mercury background level in some areas. There were also indications of depleted air, i.e., air with lower concentrations than average, being transported from the Arctic to northern Sweden resulting in a drop in TGM levels.

scholarly journals Atmospheric mercury concentrations observed at ground-based monitoring sites globally distributed in the framework of the GMOS network

2016 ◽  
Vol 16 (18) ◽  
pp. 11915-11935 ◽  
Author(s):  
Francesca Sprovieri ◽  
Nicola Pirrone ◽  
Mariantonia Bencardino ◽  
Francesco D'Amore ◽  
Francesco Carbone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Ad Hoc ◽  
Temporal Trends ◽  
Global Scale ◽  
Atmospheric Mercury ◽  
Global Network ◽  
Observation System ◽  
Large Network ◽  
Deposition Processes ◽  
The Impact

Abstract. Long-term monitoring of data of ambient mercury (Hg) on a global scale to assess its emission, transport, atmospheric chemistry, and deposition processes is vital to understanding the impact of Hg pollution on the environment. The Global Mercury Observation System (GMOS) project was funded by the European Commission (http://www.gmos.eu) and started in November 2010 with the overall goal to develop a coordinated global observing system to monitor Hg on a global scale, including a large network of ground-based monitoring stations, ad hoc periodic oceanographic cruises and measurement flights in the lower and upper troposphere as well as in the lower stratosphere. To date, more than 40 ground-based monitoring sites constitute the global network covering many regions where little to no observational data were available before GMOS. This work presents atmospheric Hg concentrations recorded worldwide in the framework of the GMOS project (2010–2015), analyzing Hg measurement results in terms of temporal trends, seasonality and comparability within the network. Major findings highlighted in this paper include a clear gradient of Hg concentrations between the Northern and Southern hemispheres, confirming that the gradient observed is mostly driven by local and regional sources, which can be anthropogenic, natural or a combination of both.

scholarly journals Origin of oxidized mercury in the summertime free troposphere over the southeastern US

2015 ◽  
Vol 15 (19) ◽  
pp. 26839-26893 ◽  
Author(s):  
V. Shah ◽  
L. Jaeglé ◽  
L. E. Gratz ◽  
J.L. Ambrose ◽  
D. A. Jaffe ◽  
...  
Keyword(s):  
Detection Limit ◽  
Transport Model ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Free Troposphere ◽  
Chemical Transport Model ◽  
Back Trajectories ◽  
Air Masses ◽  
The North ◽  
Southeastern Us

Abstract. We collected mercury observations as part of the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign over the southeastern US between 1 June and 15 July 2013. We use the GEOS-Chem chemical transport model to interpret these observations and place new constraints on bromine radical initiated mercury oxidation chemistry in the free troposphere. We find that the model reproduces the observed mean concentration of total atmospheric mercury (THg) (observations: 1.49 ± 0.16 ng m−3, model: 1.51 ± 0.08 ng m−3), as well as the vertical profile of THg. The majority (65 %) of observations of oxidized mercury (Hg(II)) are below the instrument's detection limit (detection limit per flight: 58–228 pg m−3), consistent with model-calculated Hg(II) concentrations of 0–196 ng m−3. However, for observations above the detection limit we find that modeled Hg(II) concentrations are a factor of 3 too low (observations: 212 ± 112 ng m−3, model: 67 ± 44 ng m−3). The highest Hg(II) concentrations, 300–680 pg m−3, were observed in dry (RH < 35 %) and clean air masses during two flights over Texas at 5–7 km altitude and off the North Carolina coast at 1–3 km. The GEOS-Chem model, back trajectories and observed chemical tracers for these air masses indicate subsidence and transport from the upper and middle troposphere of the subtropical anticyclones, where fast oxidation of elemental mercury (Hg(0)) to Hg(II) and lack of Hg(II) removal lead to efficient accumulation of Hg(II). We hypothesize that the most likely explanation for the model bias is a systematic underestimate of the Hg(0)+Br reaction rate. We find that sensitivity simulations with tripled bromine radical concentrations or a faster oxidation rate constant for Hg(0)+Br, result in 1.5–2 times higher modeled Hg(II) concentrations and improved agreement with the observations. The modeled tropospheric lifetime of Hg(0) against oxidation to Hg(II) decreases from 5 months in the base simulation to 2.8–1.2 months in our sensitivity simulations. In order to maintain the modeled global burden of THg, we need to increase the in-cloud reduction of Hg(II), thus leading to faster chemical cycling between Hg(0) and Hg(II). Observations and model results for the NOMADSS campaign suggest that the subtropical anticyclones are significant global sources of Hg(II).

scholarly journals Measurements of reactive chlorocarbons over the Surinam tropical rain forest: indications for strong biogenic emissions

2003 ◽  
Vol 3 (5) ◽  
pp. 5469-5512 ◽  
Author(s):  
H. A. Scheeren ◽  
J. Lelieveld ◽  
J. Williams ◽  
H. Fischer ◽  
C. Warneke
Keyword(s):  
Biomass Burning ◽  
Methyl Chloride ◽  
Global Scale ◽  
Anthropogenic Sources ◽  
Biogenic Emissions ◽  
Gas Chromatograph ◽  
Air Masses ◽  
Mixing Ratios ◽  
Potential Source ◽  
The Tropics

Abstract. Contrary to the understanding of the emissions and chemical behavior of halocarbons from anthropogenic sources (e.g. CFCs and HCFCs), the biogeochemistry of naturally emitted halocarbons is still poorly understood. We present measurements of chloromethane (methyl chloride, CH3Cl), trichloromethane (chloroform, CHCl3), dichloromethane (CH2Cl2), and tetrachloroethylene (C2Cl4) from air samples taken over the Surinam rainforest during the 1998 LBA/CLAIRE campaign. The samples were collected in stainless steel canisters on-board a Cessna Citation jet aircraft and analyzed in the laboratory using a gas chromatograph equipped with FID and ECD. The chlorocarbons we studied have atmospheric lifetimes of ~1 year or less, and appear to have significant emissions from natural sources including oceans, soils and vegetations, as well as biomass burning. These sources are primarily concentrated in the tropics (30º N-30º S). We detected an increase as a function of latitude of methyl chloride, chloroform, and tetrachloroethylene mixing ratios, in pristine air masses advected from the Atlantic Ocean toward the central Amazon. In the absence of significant biomass burning sources, we attribute this increase to biogenic emissions from the Surinam rainforest. From our measurements, we deduce fluxes from the Surinam rainforest of 7.6±1.8 μg CH3Cl m−2 h−1, 1.11±0.08g CHCl3 μm−2 h−1, and 0.36±0.07 μg C2Cl4 m−2 h−1. Extrapolated to a global scale, our emission estimates suggest a large potential source of 2 Tg CH3Cl yr−1 from tropical forests, which could account for the net budget discrepancy (underestimation of sources), as indicated previously. In addition, our estimates suggest a potential emission of 57±17 Gg C2C4 yr−1 from tropical forest soils, equal to half of the currently missing C2Cl4 sources. We hypothesize that the extensive deforestation over the last two decades relates to the observed global downward trend of atmospheric methyl chloride.

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