scholarly journals A comparison of methyl and gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Elaine Cairns
Keyword(s):  
Urban Areas ◽  
Elemental Mercury ◽  
Point Sources ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Mercury Species ◽  
Gaseous Elemental Mercury ◽  
Location Function ◽  
Air Circulation ◽  
The City

This study was carried out to compare the levels of mercury species, i.e., elemental mercury (Hg°) and methyl mercury (MeHg), in indoor and outdoor air in urban areas in Canada. Offices, laboratories for undergraduate studies, and laboratories for research, in a public building located in the downtown core of the city of Toronto, were selected. Hg° was measured using an automated mercury vapour analyzer. MeHg in the air was collected using a carbotrap, and the trapped MeHg was thermally desorbed and analyzed using a CVAFS. The results showed that both indoor MeHg and Hg° levels were related to location function and air circulation. Outdoor MeHg levels were significantly elevated, ranging between 21 and 41% of total mercury (THg) levels, compared to those reported from previous studies. Outdoor Hg° fluctuations were not found to be significantly related to temperature or sunlight exposure, and outdoor MeHg levels were connected to soil and vegetation abundance. Average indoor Hg° levels were found to be between 1.4 and 15 times higher than outdoor levels, whereas MeHg indoor levels were not consistently higher than outdoor levels. Although the mercury concentrations in the indoor environment are still lower than the safety standard for Hg° and organic mercury, they are comparable to those observed near point sources. Thus, indoor air can be a source of mercury to the atmosphere.

scholarly journals A comparison of methyl and gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Elaine Cairns
Keyword(s):  
Urban Areas ◽  
Elemental Mercury ◽  
Point Sources ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Mercury Species ◽  
Gaseous Elemental Mercury ◽  
Location Function ◽  
Air Circulation ◽  
The City

This study was carried out to compare the levels of mercury species, i.e., elemental mercury (Hg°) and methyl mercury (MeHg), in indoor and outdoor air in urban areas in Canada. Offices, laboratories for undergraduate studies, and laboratories for research, in a public building located in the downtown core of the city of Toronto, were selected. Hg° was measured using an automated mercury vapour analyzer. MeHg in the air was collected using a carbotrap, and the trapped MeHg was thermally desorbed and analyzed using a CVAFS. The results showed that both indoor MeHg and Hg° levels were related to location function and air circulation. Outdoor MeHg levels were significantly elevated, ranging between 21 and 41% of total mercury (THg) levels, compared to those reported from previous studies. Outdoor Hg° fluctuations were not found to be significantly related to temperature or sunlight exposure, and outdoor MeHg levels were connected to soil and vegetation abundance. Average indoor Hg° levels were found to be between 1.4 and 15 times higher than outdoor levels, whereas MeHg indoor levels were not consistently higher than outdoor levels. Although the mercury concentrations in the indoor environment are still lower than the safety standard for Hg° and organic mercury, they are comparable to those observed near point sources. Thus, indoor air can be a source of mercury to the atmosphere.

scholarly journals Effect of sources and meteorological conditions on the concentration and distribution of gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Daniel Prete
Keyword(s):  
Rural Areas ◽  
Elemental Mercury ◽  
Average Concentration ◽  
Meteorological Conditions ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Data Set ◽  
Gaseous Elemental Mercury ◽  
Regional Sources ◽  
High Mercury

Atmospheric gaseous elemental mercury (GEM) and meteorological parameters were monitored at two sites in downtown Toronto, Canada from Oct. 2015 to Oct. 2016 using Tekran 2537A mercury vapour analyzers. The average concentration was found to be 1.78 ± 0.89 ng/m3 for Kerr Hall North (KHN) and 1.46 ± 0.54 ng/m3 for Jorgenson Hall (JOR) site. Analysis of the data reveals that sporadic events of high mercury concentration are related to local sources. Comparing this data set with that collected in 2004 revealed that the average atmospheric GEM concentration in downtown Toronto dropped from 4.5 ng/m3 to 1.78 ng/m3. Decreases in GEM were also observed over the same period in rural areas as measured by CAMNet. The decrease might be a result of policy change, as three key national and provincial environmental policies have been enacted since 2004. The data collected in Toronto suggest GEM concentration and distribution are influenced by local and regional sources, meteorological conditions, and changes in environmental policy.

scholarly journals Effect of sources and meteorological conditions on the concentration and distribution of gaseous elemental mercury in the urban atmosphere

2021 ◽  
Author(s):  
Daniel Prete
Keyword(s):  
Rural Areas ◽  
Elemental Mercury ◽  
Average Concentration ◽  
Meteorological Conditions ◽  
Urban Atmosphere ◽  
Mercury Vapour ◽  
Data Set ◽  
Gaseous Elemental Mercury ◽  
Regional Sources ◽  
High Mercury

Atmospheric gaseous elemental mercury (GEM) and meteorological parameters were monitored at two sites in downtown Toronto, Canada from Oct. 2015 to Oct. 2016 using Tekran 2537A mercury vapour analyzers. The average concentration was found to be 1.78 ± 0.89 ng/m3 for Kerr Hall North (KHN) and 1.46 ± 0.54 ng/m3 for Jorgenson Hall (JOR) site. Analysis of the data reveals that sporadic events of high mercury concentration are related to local sources. Comparing this data set with that collected in 2004 revealed that the average atmospheric GEM concentration in downtown Toronto dropped from 4.5 ng/m3 to 1.78 ng/m3. Decreases in GEM were also observed over the same period in rural areas as measured by CAMNet. The decrease might be a result of policy change, as three key national and provincial environmental policies have been enacted since 2004. The data collected in Toronto suggest GEM concentration and distribution are influenced by local and regional sources, meteorological conditions, and changes in environmental policy.

scholarly journals Simulation of atmospheric mercury depletion events (AMDEs) during polar springtime using the MECCA box model

2008 ◽  
Vol 8 (23) ◽  
pp. 7165-7180 ◽  
Author(s):  
Z.-Q. Xie ◽  
R. Sander ◽  
U. Pöschl ◽  
F. Slemr
Keyword(s):  
Aqueous Phase ◽  
Ozone Depletion ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Box Model ◽  
Rate Coefficients ◽  
Mercury Species ◽  
Phase Reaction ◽  
Gaseous Elemental Mercury ◽  
Sea Salt Aerosol

Abstract. Atmospheric mercury depletion events (AMDEs) during polar springtime are closely correlated with bromine-catalyzed tropospheric ozone depletion events (ODEs). To study gas- and aqueous-phase reaction kinetics and speciation of mercury during AMDEs, we have included mercury chemistry into the box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere), which enables dynamic simulation of bromine activation and ODEs. We found that the reaction of Hg with Br atoms dominates the loss of gaseous elemental mercury (GEM). To explain the experimentally observed synchronous depletion of GEM and O3, the reaction rate of Hg+BrO has to be much lower than that of Hg+Br. The synchronicity is best reproduced with rate coefficients at the lower limit of the literature values for both reactions, i.e. kHg+Br≈3×10−13 and kHg+BrO≤1×10−15 cm3 molecule−1 s−1, respectively. Throughout the simulated AMDEs, BrHgOBr was the most abundant reactive mercury species, both in the gas phase and in the aqueous phase. The aqueous-phase concentrations of BrHgOBr, HgBr2, and HgCl2 were several orders of magnitude larger than that of Hg(SO3)22−. Considering chlorine chemistry outside depletion events (i.e. without bromine activation), the concentration of total divalent mercury in sea-salt aerosol particles (mostly HgCl42−) was much higher than in dilute aqueous droplets (mostly Hg(SO3)22−), and did not exhibit a diurnal cycle (no correlation with HO2 radicals).

Gaseous mercury in coastal urban areas

2010 ◽  
Vol 7 (6) ◽  
pp. 537 ◽  
Author(s):  
Anne L. Soerensen ◽  
Henrik Skov ◽  
Matthew S. Johnson ◽  
Marianne Glasius
Keyword(s):  
Urban Areas ◽  
Marine Boundary Layer ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Mercury Deposition ◽  
Mercury Emissions ◽  
Gaseous Elemental Mercury ◽  
Gaseous Mercury ◽  
Range Transport ◽  
Aquatic Food

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.

scholarly journals Variations in time and space of trace metal aerosol concentrations in urban areas and their surroundings

2011 ◽  
Vol 11 (5) ◽  
pp. 14747-14776
Author(s):  
T. Moreno ◽  
X. Querol ◽  
A. Alastuey ◽  
C. Reche ◽  
M. Cusack ◽  
...  
Keyword(s):  
Trace Metal ◽  
Urban Areas ◽  
Urban Pollution ◽  
Sea Breeze ◽  
Point Sources ◽  
Fuel Oil ◽  
Physical Parameters ◽  
Spatial And Temporal Variability ◽  
Metal Concentrations ◽  
The City

Abstract. Using an unprecedentedly large geochemical database, we compare temporal and spatial variations in inhalable trace metal background concentrations in a major city (Barcelona, Spain) and at a nearby mountainous site (Montseny) affected by the urban plume. Both sites are contaminated by technogenic metals, with V, Pb, Cu, Zn, Mn, Sn, Bi, Sb and Cd all showing upper continental crust (UCC) normalised values >1 in broadly increasing order. The highest metal concentrations usually occur during winter at Barcelona and summer in Montseny. This seasonal difference was especially marked at the remote mountain site in several elements such as Ti and Rare Earth Elements, which recorded campaign maxima, exceeding PM10 concentrations seen in Barcelona. The most common metals were Zn, Ti, Cu, Mn, Pb and V. Both V and Ni show highest concentrations in summer, and preferentially fractionate into the finest PM sizes (PM1/PM10 > 0.5) especially in Barcelona, this being attributed to regionally dispersed contamination from fuel oil combustion point sources. Within the city, hourly metal concentrations are controlled either by traffic (rush hour double peak for Cu, Sb, Sn, Ba) or industrial plumes (morning peak of Ni, Mn, Cr generated outside the city overnight), whereas at Montseny metal concentrations rise during the morning to a single, prolonged afternoon peak as contaminated air transported by the sea breeze moves into the mountains. Our exceptional database, which includes hourly measurements of chemical concentrations, demonstrates in more detail than previous studies the spatial and temporal variability of urban pollution by trace metals in a given city. Technogenic metalliferous aerosols are commonly fine in size and therefore potentially bioavailable, emphasising the case for basing urban background PM characterisation not only on physical parameters such as mass but also on sample chemistry and with special emphasis on trace metal content.

Performance of a new diffusive sampler for Hg0 determination in the troposphere

2007 ◽  
Vol 4 (2) ◽  
pp. 75 ◽  
Author(s):  
Henrik Skov ◽  
Britt T. Sørensen ◽  
Matthew S. Landis ◽  
Matthew S. Johnson ◽  
Paolo Sacco ◽  
...  
Keyword(s):  
Detection Limit ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Atmospheric Mercury ◽  
Point Sources ◽  
Gaseous Elemental Mercury ◽  
Marine Predators ◽  
Diffusive Sampler ◽  
Ambient Concentrations ◽  
Areas Of Interest

Environmental context. Mercury is of concern to both the public and to the scientific community because it is found at high levels in some marine predators, prompting the US EPA and others to make guidelines restricting the consumption of some species. Most mercury in the environment is emitted to the atmosphere, but it is not known how it is transferred from the atmosphere to the marine environment. Therefore, it is important to study the connection between emission of mercury, its transport and removal from the atmosphere. We have developed a new sampler that is inexpensive, easy to use and with a sufficiently high detection limit that it can be used to measure the low mercury concentrations in the atmosphere at a reasonable time resolution. Abstract. Mercury behaves uniquely in the atmosphere due to its volatility and long lifetime. The existing methods for measuring atmospheric mercury are either expensive or labour intensive. The present paper presents a new measurement technique, the diffusive sampler, that is portable, inexpensive, easy to use, and does not need a power supply. The sampler is sufficiently sensitive that it can measure mercury at low ambient levels with an exposure time of 1 to 3 days. The sampler is based on the Radiello diffusive sampler, which was used to collect volatile organic compounds. In the present paper, the method is validated under controlled laboratory conditions. The uptake rate of the Radiello diffusive sampler is determined using known concentrations of gaseous elemental mercury, and is measured as a function of wind speed, relative humidity and temperature. The Radiello sampler has a detection limit of 0.14 ng m–3 for 1 day of exposure and thus can be used to measure mercury concentrations at the low levels found in ambient air. The Radiello sampler is therefore useful for mapping concentrations close to sources and sinks, in addition to ambient concentrations. For example, the sampler can be used to describe the geographical extent of Arctic mercury depletion episodes where gaseous elemental mercury is removed and stays close to 0 ng m–3 for days, and it can be a powerful tool for mapping gradients around point sources and other areas of interest.

scholarly journals Network design for quantifying urban CO<sub>2</sub> emissions: Assessing trade-offs between precision and network density

2016 ◽  
Author(s):  
Alexander J. Turner ◽  
Alexis A. Shusterman ◽  
Brian C. McDonald ◽  
Virginia Teige ◽  
Robert A Harley ◽  
...  
Keyword(s):  
Co2 Emissions ◽  
Urban Areas ◽  
Cost Effective ◽  
Point Sources ◽  
Urban Region ◽  
Dense Network ◽  
Industrial Facilities ◽  
Trade Offs ◽  
Combined Uncertainty ◽  
The City

Abstract. The majority of anthropogenic CO2 emissions are attributable to urban areas. While the emissions from urban electricity generation often occur in locations remote from consumption, many of the other emissions occur within the city limits. Evaluating the effectiveness of strategies for controlling these emissions depends on our ability to observe urban CO2 emissions and attribute them to specific activities. Cost effective strategies for doing so have yet to be described. Here we characterize the ability of a prototype measurement network, modeled after the BEACO2N network, in combination with an inverse model based on WRF-STILT to improve our understanding of urban emissions. The pseudo-measurement network includes 34 sites at roughly 2 km spacing covering an area of roughly 400 km2. The model uses an hourly 1 × 1 km2 emission inventory and 1 × 1 km2 meteorological calculations. We perform an ensemble of Bayesian atmospheric inversions to sample the combined effects of uncertainties of the pseudo-measurements and the model. We vary the estimates of the combined uncertainty of the pseudo-observations and model over a range of 20 ppm to 0.005 ppm and vary the number of sites from 1 to 34. We use these inversions to develop statistical models that estimate the efficacy of the combined model-observing system at reducing uncertainty in CO2 emissions. We examine uncertainty in estimated CO2 fluxes at the urban scale, as well as for sources embedded within the city such as a line source (e.g., a highway) or a point source (e.g., emissions from the stacks of small industrial facilities). We find that a dense network with moderate precision is the preferred setup for estimating area, line, and point sources from a combined uncertainty and cost perspective. The dense network considered here could estimate weekly CO2 emissions from an urban region with less than 5 % error, given our characterization of the combined observation and model uncertainty.

scholarly journals Statistical exploration of gaseous elemental mercury (GEM) measured at Cape Point from 2007 to 2011

2015 ◽  
Vol 15 (18) ◽  
pp. 10271-10280 ◽  
Author(s):  
A. D. Venter ◽  
J. P. Beukes ◽  
P. G. van Zyl ◽  
E.-G. Brunke ◽  
C. Labuschagne ◽  
...  
Keyword(s):  
South Africa ◽  
Urban Areas ◽  
Calculated Data ◽  
Elemental Mercury ◽  
Back Trajectory ◽  
Cluster Solution ◽  
Atmospheric Parameters ◽  
Air Mass ◽  
Gaseous Elemental Mercury ◽  
Gem Data

Abstract. The authors evaluated continuous high-resolution gaseous elemental mercury (GEM) data from the Cape Point Global Atmosphere Watch (CPT GAW) station with different statistical analysis techniques. GEM data were evaluated by cluster analysis and the results indicated that two clusters, separated at 0.904 ng m−3, existed. The air mass history for the two-cluster solution was investigated by means of back-trajectory analysis. The air mass back-trajectory net result showed lower GEM concentrations originating from the sparsely populated semi-arid interior of South Africa and the marine environment, whereas higher GEM concentrations originated predominately along the coast of South Africa that most likely coincide with trade routes and industrial activities in urban areas along the coast. Considering the net result from the air mass back-trajectories, it is evident that not all low GEM concentrations are from marine origin, and similarly, not all high GEM concentrations have a terrestrial origin. Equations were developed by means of multi-linear regression (MLR) analysis that allowed for the estimation and/or prediction of atmospheric GEM concentrations from other atmospheric parameters measured at the CPT GAW station. These equations also provided some insight into the relation and interaction of GEM with other atmospheric parameters. Both measured and MLR calculated data confirm a decline in GEM concentrations at CPT GAW over the period evaluated.

scholarly journals Simulation of atmospheric mercury depletion events (AMDEs) during polar springtime using the MECCA box model

2008 ◽  
Vol 8 (4) ◽  
pp. 13197-13232 ◽  
Author(s):  
Z.-Q. Xie ◽  
R. Sander ◽  
U. Pöschl ◽  
F. Slemr
Keyword(s):  
Aqueous Phase ◽  
Ozone Depletion ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Box Model ◽  
Rate Coefficients ◽  
Mercury Species ◽  
Phase Reaction ◽  
Gaseous Elemental Mercury ◽  
Sea Salt Aerosol

Abstract. Atmospheric mercury depletion events (AMDEs) during polar springtime are closely correlated with bromine-catalyzed tropospheric ozone depletion events (ODEs). To study gas- and aqueous-phase reaction kinetics and speciation of mercury during AMDEs, we have included mercury chemistry into the box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere), which enables dynamic simulation of bromine activation and ODEs. We found that the reaction of Hg with Br atoms dominates the loss of gaseous elemental mercury (GEM). To explain the experimentally observed synchronous destruction of Hg and O3, the reaction rate of Hg+BrO has to be much lower than that of Hg+Br. The synchronicity is best reproduced with rate coefficients at the lower limit of the literature values for both reactions, i.e. kHg+Br≈3×10-13 and kHg+BrO≤1×10-15cm3 mol-1 s-1, respectively. Throughout the simulated AMDEs, BrHgOBr was the most abundant reactive mercury species, both in the gas phase and in the aqueous phase. The aqueous phase concentrations of BrHgOBr, HgBr2, and HgCl2 were several orders of magnitude larger than that of Hg(SO3)2-2. Considering chlorine chemistry outside depletion events (i.e. without bromine activation), the concentration of total divalent mercury in sea-salt aerosol particles (mostly HgCl2) was much higher than in dilute aqueous droplets (mostly Hg(SO3)2-2), and did not exhibit a diurnal cycle (no correlation with HO2 radicals).

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