Atmospheric Mercury Speciation:  Laboratory and Field Evaluation of a Mist Chamber Method for Measuring Reactive Gaseous Mercury

2001 ◽  
Vol 35 (1) ◽  
pp. 170-177 ◽  
Author(s):  
Wilmer J. Stratton ◽  
Steven E. Lindberg ◽  
Christopher J. Perry
2012 ◽  
Vol 12 (11) ◽  
pp. 29203-29233 ◽  
Author(s):  
H. Timonen ◽  
J. L. Ambrose ◽  
D. A. Jaffe

Abstract. Mercury (Hg) is a neurotoxin that bioaccumulates in the food chain. Mercury is emitted to the atmosphere primarily in its elemental form, which has a long lifetime allowing global transport. It is known that atmospheric oxidation of gaseous elemental mercury (GEM) generates reactive gaseous mercury (RGM) which plays an important role in the atmospheric mercury cycle by enhancing the rate of mercury deposition to ecosystems. However, the primary GEM oxidants, and the sources and chemical composition of RGM are poorly known. Using speciated mercury measurements conducted at the Mt. Bachelor Observatory since 2005 we present two previously unidentified sources of RGM to the free troposphere (FT). Firstly, we observed elevated RGM concentrations, large RGM/GEM-ratios, and anti-correlation between RGM and GEM during Asian long-rang transport events, demonstrating that RGM is formed from GEM by in-situ oxidation in some anthropogenic pollution plumes in the FT. During the Asian pollution events the measured RGM/GEM-ratios reached peak values, up to ~0.20, which are significantly larger than ratios typically measured (RGM/GEM < 0.05) in the Asian source region. Secondly, we observed very high RGM levels – the highest reported in the FT – in clean air masses that were processed upwind of Mt. Bachelor Observatory over the Pacific Ocean. The high RGM concentrations (up to 700 pg m−3), high RGM/GEM-ratios (up to 1), and very low ozone levels during these events provide the first observational evidence indicating significant GEM oxidation in the lower FT. The identification of these processes changes our conceptual understanding of the formation and distribution of oxidized Hg in the global atmosphere.


2014 ◽  
Vol 14 (5) ◽  
pp. 2219-2231 ◽  
Author(s):  
A. Steffen ◽  
J. Bottenheim ◽  
A. Cole ◽  
R. Ebinghaus ◽  
G. Lawson ◽  
...  

Abstract. Ten years of atmospheric mercury speciation data and 14 years of mercury in snow data from Alert, Nunavut, Canada, are examined. The speciation data, collected from 2002 to 2011, includes gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM). During the winter-spring period of atmospheric mercury depletion events (AMDEs), when GEM is close to being completely depleted from the air, the concentration of both PHg and RGM rise significantly. During this period, the median concentrations for PHg is 28.2 pgm−3 and RGM is 23.9 pgm−3, from March to June, in comparison to the annual median concentrations of 11.3 and 3.2 pgm−3 for PHg and RGM, respectively. In each of the ten years of sampling, the concentration of PHg increases steadily from January through March and is higher than the concentration of RGM. This pattern begins to change in April when the levels of PHg peak and RGM begin to increase. In May, the high PHg and low RGM concentration regime observed in the early spring undergoes a transition to a regime with higher RGM and much lower PHg concentrations. The higher RGM concentration continues into June. The transition is driven by the atmospheric conditions of air temperature and particle availability. Firstly, a high ratio of the concentrations of PHg to RGM is reported at low temperatures which suggests that oxidized gaseous mercury partitions to available particles to form PHg. Prior to the transition, the median air temperature is −24.8 °C and after the transition the median air temperature is −5.8 °C. Secondly, the high PHg concentrations occur in the spring when high particle concentrations are present. The high particle concentrations are principally due to Arctic haze and sea salts. In the snow, the concentrations of mercury peak in May for all years. Springtime deposition of total mercury to the snow at Alert peaks in May when atmospheric conditions favour higher levels of RGM. Therefore, the conditions in the atmosphere directly impact when the highest amount of mercury will be deposited to the snow during the Arctic spring.


2010 ◽  
Vol 7 (6) ◽  
pp. 537 ◽  
Author(s):  
Anne L. Soerensen ◽  
Henrik Skov ◽  
Matthew S. Johnson ◽  
Marianne Glasius

Environmental context Mercury is a neurotoxin that bioaccumulates in the aquatic food web. Atmospheric emissions from urban areas close to the coast could cause increased local mercury deposition to the ocean. Our study adds important new data to the current limited knowledge on atmospheric mercury emissions and dynamics in coastal urban areas. Abstract Approximately 50% of primary atmospheric mercury emissions are anthropogenic, resulting from e.g. emission hotspots in urban areas. Emissions from urban areas close to the coast are of interest because they could increase deposition loads to nearby coastal waters as well as contribute to long range transport of mercury. We present results from measurements of gaseous elemental mercury (GEM) and reactive gaseous mercury (RGM) in 15 coastal cities and their surrounding marine boundary layer (MBL). An increase of 15–90% in GEM concentration in coastal urban areas was observed compared with the remote MBL. Strong RGM enhancements were only found in two cities. In urban areas with statistically significant GEM/CO enhancement ratios, slopes between 0.0020 and 0.0087 ng m–3 ppb–1 were observed, which is consistent with other observations of anthropogenic enhancement. The emission ratios were used to estimate GEM emissions from the areas. A closer examination of data from Sydney (Australia), the coast of Chile, and Valparaiso region (Chile) in the southern hemisphere, is presented.


2011 ◽  
Vol 11 (11) ◽  
pp. 30053-30089 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
P. Liang ◽  
H. Zhang ◽  
J. Ji ◽  
...  

Abstract. Measurements of speciated atmospheric mercury were conducted at a remote mountain-top station (WLG) at the edge of northeastern part of the Qinghai-Xizang Plateau, western China. Mean concentrations of total gaseous mercury (TGM), particulate mercury (PHg), and reactive gaseous mercury (RGM) during the whole sampling campaign were 1.98 &amp;pm; 0.98 ng m−3, 19.4 &amp;pm; 18.1 pg m−3, and 7.4 &amp;pm; 4.8 pg m−3, respectively. Levels of speciated Hg at WLG were slightly higher than those reported from remote areas of North America and Europe. Both regional emissions and long-rang transport played a remarkable role in the distribution of TGM and PHg in ambient air at WLG, whereas RGM showed major links to the regional sources, likely as well as the in-situ productions by photochemical processes. Regional sources for speciated Hg were mostly located to the east of WLG, which is the most developed areas of Qinghai province and accounted for most of the province's anthropogenic Hg emissions. Potential source contribution function (PSCF) results showed a strong impact of long-range transport from eastern Gansu, western Ningxia and Shanxi Province, with good accordance with locations of urban areas and industrial centers. Moreover, we found that northern India was also an important source region of WLG during the sampling campaign, and this is the first time of direct evidence of long-range transport of atmospheric Hg from India to northeastern Tibetan Plateau. Seasonal and diurnal variations of TGM were in contrast with most of the previous studies in China, with relatively higher levels in warm seasons and night, respectively. The temporal trend of TGM also highlighted the impact of long-range transport on the distribution of TGM in ambient air at WLG.


1993 ◽  
Vol 5 (3) ◽  
pp. 323-326 ◽  
Author(s):  
S. J. de Mora ◽  
J. E. Patterson ◽  
D. M. Bibby

The first extended baseline studies of total gaseous mercury (TGM) and dimethylmercury (DMM) in Antarctica are reported. Mean TGM concentrations of 0.52, 0.60 and 0.52 ng m−3 were obtained for three consecutive years at the southern tip of Ross Island (77°S). The levels of DMM in Antarctica are less than 10% of the TGM, and frequently fall below the limit of detection. These results represent the lowest TGM concentrations recorded globally and extend into polar regions the observation of a decrease in atmospheric mercury concentration with increasing latitude.


Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 387
Author(s):  
Linghui Meng ◽  
Charles T. Driscoll ◽  
Mario Montesdeoca ◽  
Huiting Mao

In order to obtain a better perspective of the impacts of brownfields on the land–atmosphere exchange of mercury in urban areas, total gaseous mercury (TGM) was measured at two heights (1.8 m and 42.7 m) prior to 2011–2012 and after 2015–2016 for the remediation of a brownfield and installation of a parking lot adjacent to the Syracuse Center of Excellence in Syracuse, NY, USA. Prior to brownfield remediation, the annual average TGM concentrations were 1.6 ± 0.6 and 1.4 ± 0.4 ng · m − 3 at the ground and upper heights, respectively. After brownfield remediation, the annual average TGM concentrations decreased by 32% and 22% at the ground and the upper height, respectively. Mercury soil flux measurements during summer after remediation showed net TGM deposition of 1.7 ng · m − 2 · day − 1 suggesting that the site transitioned from a mercury source to a net mercury sink. Measurements from the Atmospheric Mercury Network (AMNet) indicate that there was no regional decrease in TGM concentrations during the study period. This study demonstrates that evasion from mercury-contaminated soil significantly increased local TGM concentrations, which was subsequently mitigated after soil restoration. Considering the large number of brownfields, they may be an important source of mercury emissions source to local urban ecosystems and warrant future study at additional locations.


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