scholarly journals Observations of atmospheric mercury in China: a critical review

2015 ◽  
Vol 15 (8) ◽  
pp. 11925-11983 ◽  
Author(s):  
X. W. Fu ◽  
H. Zhang ◽  
X. Wang ◽  
B. Yu ◽  
C.-J. Lin ◽  
...  
Keyword(s):  
North America ◽  
Long Range ◽  
Dry Deposition ◽  
Critical Review ◽  
Urban Areas ◽  
Wet Deposition ◽  
Long Range Transport ◽  
Deposition Fluxes ◽  
Wide Range ◽  
Range Transport

Abstract. China is presently the largest contributor of global anthropogenic Hg emission to the atmosphere. Over the past two decades, extensive studies have been conducted to characterize the concentration and speciation of atmospheric Hg in China. These studies provide important insight into the spatial and temporal distributions of atmospheric Hg species in China through ground-based measurements at a wide range of altitude over diverse geographical locations, and cruise and flight campaigns. In this critical review, we synthesize the available data to date to delineate the spatial and temporal patterns of atmospheric Hg, the long-range transport pattern of atmospheric Hg, and the impacts of Hg emissions on atmospheric Hg distribution and deposition in China. Atmospheric Hg species in China are substantially elevated compared to the background values in the Northern Hemisphere. The highly elevated Hg levels in Chinese urban areas were derived from local and regional anthropogenic and natural emissions, while long-range transport plays an important role in the atmospheric Hg concentration in remote areas. Preliminary studies suggested that atmosphere GEM levels are increasing at an urban and remote sites over the last decade, which were likely caused by the increasing anthropogenic emissions. The anthropogenic emission quantity in China estimated through the observed concentration ratios of GEM to CO (observed from 2001 to 2013) is approximately 983 t in 2009, ~ 3 folds of the published anthropogenic GEM emission inventories using activity data. Wet deposition fluxes of Hg in remote regions are low but the fluxes in Chinese urban areas are much higher than that in urban areas of North America and Europe. Dry deposition fluxes of Hg measured as litterfall input in forest areas of China were 2.5–9.0 times higher than the wet deposition fluxes and 1.8–13.6 times higher than the dry deposition fluxes of Hg in North America and Europe, suggesting that dry deposition to forest may be an important sink of atmospheric Hg in China.

scholarly journals Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) to quantify long-range transport of East Asian sulfur to Canada

2008 ◽  
Vol 8 (11) ◽  
pp. 2999-3014 ◽  
Author(s):  
A. van Donkelaar ◽  
R. V. Martin ◽  
W. R. Leaitch ◽  
A. M. Macdonald ◽  
T. W. Walker ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Long Range ◽  
East Asian ◽  
Chemical Transport ◽  
Long Range Transport ◽  
Free Troposphere ◽  
Range Transport ◽  
Transport Experiment ◽  
Sulfur Emissions

Abstract. We interpret a suite of satellite, aircraft, and ground-based measurements over the North Pacific Ocean and western North America during April–May 2006 as part of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign to understand the implications of long-range transport of East Asian emissions to North America. The Canadian component of INTEX-B included 33 vertical profiles from a Cessna 207 aircraft equipped with an aerosol mass spectrometer. Long-range transport of organic aerosols was insignificant, contrary to expectations. Measured sulfate plumes in the free troposphere over British Columbia exceeded 2 μg/m3. We update the global anthropogenic emission inventory in a chemical transport model (GEOS-Chem) and use it to interpret the observations. Aerosol Optical Depth (AOD) retrieved from two satellite instruments (MISR and MODIS) for 2000–2006 are analyzed with GEOS-Chem to estimate an annual growth in Chinese sulfur emissions of 6.2% and 9.6%, respectively. Analysis of aircraft sulfate measurements from the NASA DC-8 over the central Pacific, the NSF C-130 over the east Pacific and the Cessna over British Columbia indicates most Asian sulfate over the ocean is in the lower free troposphere (800–600 hPa), with a decrease in pressure toward land due to orographic effects. We calculate that 56% of the measured sulfate between 500–900 hPa over British Columbia is due to East Asian sources. We find evidence of a 72–85% increase in the relative contribution of East Asian sulfate to the total burden in spring off the northwest coast of the United States since 1985. Campaign-average simulations indicate anthropogenic East Asian sulfur emissions increase mean springtime sulfate in Western Canada at the surface by 0.31 μg/m3 (~30%) and account for 50% of the overall regional sulfate burden between 1 and 5 km. Mean measured daily surface sulfate concentrations taken in the Vancouver area increase by 0.32 μg/m3 per 10% increase in the simulated fraction of Asian sulfate, and suggest current East Asian emissions episodically degrade local air quality by more than 1.5 μg/m3.

Radioactivity measurements in the atmosphere and water column of Rogoznica Lake (central Adriatic)

2021 ◽  
Author(s):  
Ivana Tucaković ◽  
Sarah Mateša ◽  
Ivana Coha ◽  
Marija Marguš ◽  
Milan Čanković ◽  
...  
Keyword(s):  
Water Column ◽  
Long Range ◽  
Lake Water ◽  
Dry Deposition ◽  
Long Range Transport ◽  
Atmospheric Input ◽  
Air Masses ◽  
Activity Concentrations ◽  
Range Transport ◽  
Radionuclide Activity

<p>Croatian Science Foundation MARRES project (MARine lake (Rogoznica) as a model for EcoSystem functioning in a changing environment) aims to investigate the unique environment (slow exchange of seawater with the sea; atmospheric input is the only source of freshwater) of the marine lake which is an example of highly stratified (permanent anoxia bellow 9 m depth), and by climate changes affected marine system in the middle of the eastern Adriatic coast (43.53° N, 15.95° E). The area of the lake is characterized by the extensive tourism and mariculture, and the low impact of local industrial activities. It is also affected by the combined influence of long-range transport of air masses and local emissions (open-fire events).</p><p>An important part of the project is focused on the exchange and interaction between atmosphere, water column and sediment by measuring the atmospheric input (wet and dry deposition) of sulphur compounds, organic carbon, trace metals and radionuclides (Be-7, Pb-210).</p><p>This work for the first time will present the current state of the measurements of radioactivity in the Rogoznica lake area, including samples of aerosol particulate matter, PM2.5 < 2.5 um, rainwater and lake water column. Namely, the concentrations of Be-7 and Pb-210 in PM2.5 are measured to determine and correlate the dynamics of particle transport, meteorological information, especially origin of air masses and seasonal variation of PM2.5. While presence of Be-7 indicates the recent wet or dry deposition from the upper parts of the atmosphere, Pb-210 may be used as a tracer for continental air masses. Therefore, it can also indicate the influence of the pollution induced by human activity. Regarding that, special attention will be paid to compare results before and during the Covid-19 lockdown periods.</p><p>So far, preliminary results do not show significant difference in PM2.5 masses and measured radionuclide activity concentrations for the lockdown period. Be-7 and Pb-210 were regularly detected in aerosols collected on a glass fiber filters during a one-week sampling periods with the air flow rate of 2.3 m<sup>3</sup>/h. Their activity concentrations are determined by gamma spectrometry using High Purity Germanium detectors. The results are found to be correlated with PM2.5 masses, ranging from 2.9 to 12.2 Bq/m<sup>3</sup> for Be-7 and from 0.5 to 2.5 Bq/m<sup>3</sup> for Pb-210. First analyses show that the highest values can be related to the long-range transport of air masses and to the recorded near open-fire event. As expected, Be-7 is also detected in almost every rainwater sample (event), with the activity concentration up to 5.6 Bq/L, while low activities of Pb-210 are detected only sporadically. Related to that, Be-7 is detected in lake water column as well, but only in the surface layer and in samples collected during, or immediately after the rain events. </p><p>Dynamics and seasonal variation of radionuclide activity concentrations in here studied samples will be discussed, and the relationships with some meteorological parameters (temperature, wind speed, relative humidity, precipitation level) as well as local and long-range transport and physico-chemical conditions in the lake water column will be established.</p>

scholarly journals Parametrisation of the orographic enhancement of precipitation and deposition in a long-term, long-range transport model

2000 ◽  
Vol 18 (11) ◽  
pp. 1447-1466 ◽  
Author(s):  
D. S. Lee ◽  
R. D. Kingdon ◽  
J. A. Garland ◽  
B. M. R. Jones
Keyword(s):  
Sulfur Dioxide ◽  
Long Range ◽  
Wet Deposition ◽  
Enhancement Factor ◽  
Long Range Transport ◽  
Orographic Precipitation ◽  
Range Transport ◽  
Orographic Enhancement ◽  
The Uk

Abstract. Orographic enhancement of wet deposition arising from the 'seeder-feeder' effect is, by necessity, highly parametrised in long-range transport models of acid deposition that are long-term (i.e. annual average) and spatially resolved at tens of kilometres. Here, we describe a mechanistic approach to the incorporation of these mechanisms into such a model. The model formulation required the following: precipitation rate by direction and quantification of the fractions that are orographic and non-orographic; treatment of the fast oxidation of sulfur dioxide in clouds; the directionality of the seeder-feeder process; and a quantitative basis for increasing wet deposition factors to account for the seeder-feeder process. The directionality of non-orographic precipitation was determined from meteorological data at 47 sites across the UK. Orographic precipitation varies on a much finer scale than can be interpolated from measurements, and thus a modelling approach was adopted. The directionality of the seeder-feeder effect was taken from measurements. The enhancement factor of the orographic component of precipitation, assumed to represent feeder-rain, was determined from a review of measurements. Fast oxidation of sulfur dioxide is an observed phenomenon in cap-cloud, but limited in duration. An adjustment was made to the sulfur dioxide oxidation rate in the model in locations where cap-cloud was assumed to be present. The results from the model were compared with UK deposition budgets and enhanced wet deposition maps. The revised parametrisation underestimated the UK wet deposition budgets of oxidised N and S, but spatial patterns of deposition were improved for much of the UK. It was concluded that this was a satisfactory outcome given the constraints of the statistical approach of weighting of deposition at receptors utilising straight line trajectories. The sensitivity of the model to directional constraints of seeder-feeder enhancement was tested and it was concluded that a fairly narrow constraint resulted in similar estimations to a broader one, and the broader constraint was thus adopted as frontal conditions which result in the process arrive from a fairly broad band of directions. When enhancement was allowed to occur from all directions, UK wet deposition of oxidised N and S was increased by 10%. The sensitivity to the enhancement factor on wet deposition was tested and found to be relatively robust. An increase in the enhancement factor from 2 to 6 resulted in increases in UK wet deposition of oxidised N and S of 9 and 6%, respectively.Key words: Atmospheric composition and structure (pollution – urban and regional) – Meteorology and atmospheric dynamics (precipitation)

Long-Range Transport of Anthropogenically and Naturally Produced Particulate Matter in the Mediterranean and North Atlantic: Current State of Knowledge

2007 ◽  
Vol 46 (8) ◽  
pp. 1230-1251 ◽  
Author(s):  
George Kallos ◽  
Marina Astitha ◽  
Petros Katsafados ◽  
Chris Spyrou
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
North America ◽  
Atlantic Ocean ◽  
Long Range ◽  
Saharan Dust ◽  
Long Range Transport ◽  
Transport And Transformation ◽  
New Findings ◽  
Range Transport

Abstract During the past 20 years, organized experimental campaigns as well as continuous development and implementation of air-pollution modeling have led to significant gains in the understanding of the paths and scales of pollutant transport and transformation in the greater Mediterranean region (GMR). The work presented in this paper has two major objectives: 1) to summarize the existing knowledge on the transport paths of particulate matter (PM) in the GMR and 2) to illustrate some new findings related to the transport and transformation properties of PM in the GMR. Findings from previous studies indicate that anthropogenically produced air pollutants from European sources can be transported over long distances, reaching Africa, the Atlantic Ocean, and North America. The PM of natural origin, like Saharan dust, can be transported toward the Atlantic Ocean and North America mostly during the warm period of the year. Recent model simulations and studies in the area indicate that specific long-range transport patterns of aerosols, such as the transport from Asia and the Indian Ocean, central Africa, or America, have negligible or at best limited contribution to air-quality degradation in the GMR when compared with the other sources. Also, new findings from this work suggest that the imposed European Union limits on PM cannot be applicable for southern Europe unless the origin (natural or anthropogenic) of the PM is taken into account. The impacts of high PM levels in the GMR are not limited only to air quality, but also include serious implications for the water budget and the regional climate. These are issues that require extensive investigation because the processes involved are complex, and further model development is needed to include the relevant physicochemical processes properly.

scholarly journals Analysis of aircraft and satellite measurements from the intercontinental chemical transport experiment (INTEX-B) to quantify long-range transport of East Asian Sulfur to Canada

2008 ◽  
Vol 8 (1) ◽  
pp. 4017-4057 ◽  
Author(s):  
A. van Donkelaar ◽  
R. V. Martin ◽  
W. R. Leaitch ◽  
A. M. Macdonald ◽  
T. W. Walker ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Long Range ◽  
East Asian ◽  
Chemical Transport ◽  
Long Range Transport ◽  
Free Troposphere ◽  
Range Transport ◽  
Transport Experiment ◽  
Sulfur Emissions

Abstract. We interpret a suite of satellite, aircraft, and ground-based measurements over the North Pacific Ocean and western North America during April–May 2006 as part of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign to understand the implications of long-range transport of East Asian emissions to North America. The Canadian component of INTEX-B included 33 vertical profiles from a Cessna 207 aircraft equipped with an aerosol mass spectrometer. Long-range transport of organic aerosols was insignificant. Measured sulfate plumes in the free troposphere over British Columbia exceeded 1 μg/m3. We update the global anthropogenic emission inventory in a chemical transport model (GEOS-Chem) and use it to interpret the observations. Trends in Aerosol Optical Depth (AOD) retrieved from two satellite instruments (MISR and MODIS) for 2000–2006 are analyzed with GEOS-Chem to estimate an annual growth in Chinese sulfur emissions of 6.2% and 9.6%, respectively. Analysis of aircraft sulfate measurements from the NASA DC-8 over the central Pacific, the NSF C-130 over the east Pacific and the Cessna over British Columbia indicates most Asian sulfate over the ocean is in the lower free troposphere (800–600 hPa), with a decrease in pressure toward land due to orographic effects. We calculate that 63% of the measured sulfate at 600 hPa over British Columbia is due to East Asian sources. Simulation of INTEX-B and May 1985 aircraft measurements off the northwest coast of the United States reveals a 2.4–3.4 fold increase in the relative contribution of East Asian sulfate to the total burden. Campaign-average simulations indicate anthropogenic East Asian sulfur emissions increase mean springtime sulfate in Western Canada at the surface by 0.14–0.19 μg/m3 (~30%) and account for 40% of the overall regional sulfate burden between 1 and 5 km. Mean measured daily surface sulfate concentrations taken in the Vancouver area increase by 0.27 μg/m3 per 10% increase in the simulated fraction of Asian sulfate, suggesting current East Asian emissions degrade local air quality.

scholarly journals Atmospheric total gaseous mercury (TGM) concentrations and wet and dry deposition of mercury at a high-altitude mountain peak in south China

2009 ◽  
Vol 9 (6) ◽  
pp. 23465-23504 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
Z. Q. Dong ◽  
R. S. Yin ◽  
J. X. Wang ◽  
...  
Keyword(s):  
South China ◽  
Dry Deposition ◽  
Urban Areas ◽  
Wet Deposition ◽  
Ambient Air ◽  
Total Gaseous Mercury ◽  
Deposition Fluxes ◽  
Wet And Dry Deposition ◽  
Gaseous Mercury ◽  
Seasonal And Diurnal Variations

Abstract. China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric total gaseous mercury (TGM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Wet and dry deposition fluxes of Hg were also calculated following collection of precipitation, throughfall and litterfall. Atmospheric TGM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China, indicating great emissions of Hg in central, south and southwest China. Seasonal and diurnal variations of TGM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Wet deposition of Hg was quite low, while its dry deposition of Hg (litterfall + throughfall-direct wet deposition) constituted a major portion of total deposition (~88% for total mercury (THg) and 84% for methyl mercury (MeHg)). This highlights the importance of vegetation to Hg atmospheric cycling. In a remote forest ecosystem of China, dry deposition of TGM, especially gaseous elemental mercury (GEM), was very important for the depletion of atmospheric Hg. Elevated TGM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated Hg dry deposition fluxes observed in Mt. Leigong.

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