scholarly journals Gaseous Oxidized Mercury Dry Deposition Measurements in the Southwestern USA: A Comparison between Texas, Eastern Oklahoma, and the Four Corners Area

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Mark E. Sather ◽  
Shaibal Mukerjee ◽  
Kara L. Allen ◽  
Luther Smith ◽  
Johnson Mathew ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Dry Deposition ◽  
Passive Samplers ◽  
Monitoring Site ◽  
Rate Estimate ◽  
Surrogate Surface ◽  
Utility Boilers ◽  
Four Corners ◽  
Southwestern Usa ◽  
Gaseous Oxidized Mercury

Gaseous oxidized mercury (GOM) dry deposition measurements using aerodynamic surrogate surface passive samplers were collected in central and eastern Texas and eastern Oklahoma, from September 2011 to September 2012. The purpose of this study was to provide an initial characterization of the magnitude and spatial extent of ambient GOM dry deposition in central and eastern Texas for a 12-month period which contained statistically average annual results for precipitation totals, temperature, and wind speed. The research objective was to investigate GOM dry deposition in areas of Texas impacted by emissions from coal-fired utility boilers and compare it with GOM dry deposition measurements previously observed in eastern Oklahoma and the Four Corners area. Annual GOM dry deposition rate estimates were relatively low in Texas, ranging from 0.1 to 0.3 ng/m2h at the four Texas monitoring sites, similar to the 0.2 ng/m2h annual GOM dry deposition rate estimate recorded at the eastern Oklahoma monitoring site. The Texas and eastern Oklahoma annual GOM dry deposition rate estimates were at least four times lower than the highest annual GOM dry deposition rate estimate previously measured in the more arid bordering western states of New Mexico and Colorado in the Four Corners area.

scholarly journals Gaseous oxidized mercury dry deposition measurements in the Four Corners area and Eastern Oklahoma, U.S.A.

2013 ◽  
Vol 4 (2) ◽  
pp. 168-180 ◽  
Author(s):  
Mark E. Sather ◽  
Shaibal Mukerjee ◽  
Luther Smith ◽  
Johnson Mathew ◽  
Clarence Jackson ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Four Corners ◽  
Gaseous Oxidized Mercury

scholarly journals Field comparison of dry deposition samplers for collection of atmospheric mineral dust: results from single-particle characterization

2019 ◽  
Vol 12 (12) ◽  
pp. 6647-6665 ◽  
Author(s):  
Andebo Waza ◽  
Kilian Schneiders ◽  
Jan May ◽  
Sergio Rodríguez ◽  
Bernd Epple ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fluid Dynamics ◽  
Scanning Electron Microscopy ◽  
Deposition Rate ◽  
Dry Deposition ◽  
Deposition Velocity ◽  
Passive Samplers ◽  
Dust Deposition ◽  
Deposition Velocities ◽  
Scanning Electron

Abstract. Frequently, passive dry deposition collectors are used to sample atmospheric dust deposition. However, there exists a multitude of different instruments with different, usually not well-characterized sampling efficiencies. As a result, the acquired data might be considerably biased with respect to their size representativity and, as a consequence, also composition. In this study, individual particle analysis by automated scanning electron microscopy coupled with energy-dispersive X-ray analysis was used to characterize different, commonly used passive samplers with respect to their size-resolved deposition rate and concentration. This study focuses on the microphysical properties, i.e., the aerosol concentration and deposition rates as well as the particle size distributions. In addition, computational fluid dynamics modeling was used in parallel to achieve deposition velocities from a theoretical point of view. Scanning electron microscopy (SEM)-calculated deposition rate measurements made using different passive samplers show a disagreement among the samplers. Modified Wilson and Cooke (MWAC) and Big Spring Number Eight (BSNE) – both horizontal flux samplers – collect considerably more material than the flat plate and Sigma-2 samplers, which are vertical flux samplers. The collection efficiency of MWAC increases for large particles in comparison to Sigma-2 with increasing wind speed, while such an increase is less observed in the case of BSNE. A positive correlation is found between deposition rate and PM10 concentration measurements by an optical particle spectrometer. The results indicate that a BSNE and Sigma-2 can be good options for PM10 measurement, whereas MWAC and flat-plate samplers are not a suitable choice. A negative correlation was observed in between dust deposition rate and wind speed. Deposition velocities calculated from different classical deposition models do not agree with deposition velocities estimated using computational fluid dynamics (CFD) simulations. The deposition velocity estimated from CFD was often higher than the values derived from classical deposition velocity models. Moreover, the modeled deposition velocity ratios between different samplers do not agree with the observations.

scholarly journals Relationships between Passive Sampler and Continuous Ozone (O3) Measurement Data in Ecological Effects Research

2001 ◽  
Vol 1 ◽  
pp. 593-601 ◽  
Author(s):  
S. Krupa ◽  
M. Nosal
Keyword(s):  
Continuous Monitoring ◽  
Passive Sampling ◽  
Passive Sampler ◽  
Ecological Effects ◽  
Passive Samplers ◽  
Cumulative Exposure ◽  
Generic Model ◽  
Monitoring Site ◽  
Frequency Distributions ◽  
Continuous Monitor

In ecological effects research, there is a rapid increase in the application of passive sampling techniques for measuring ambient ozone (O3) concentrations. Passive samplers provide data on cumulative exposures of a plant to a pollutant. However, O3is not an accumulative contaminant within the plant tissue, and use of prolonged passive sampling durations cannot account for the dynamics of the occurrences of O3that have a significant influence on the plant response. Therefore, a stochastic Weibull probability model was previously developed and applied to a site in Washington State (1650 m MSL) to simulate the cumulative exposure data from a passive sampler, to mimic the corresponding frequency distributions of hourly O3concentrations that would otherwise have been obtained by continuous monitoring. At that site the correlation between the actual passive sampler and the continuous monitor data was R2 = 0.74. The simulation of the hourly O3data was based on and compared with the results obtained from a colocated continuous monitor. In this paper we report the results of the model application to data from an unrelated monitoring site (New Hampshire, 476 m MSL) with poor correlation between the passive sampling and continuous monitoring (R2 = 0.24). In addition, as opposed to the previous work, we provide comparisons of the frequency distributions of the hourly O3concentrations obtained by the simulation and the actual continuous monitoring. In spite of the major difference in the R2 values, at both sites the simulation provided very satisfactory results within the 95% confidence interval, suggesting its broad applicability. The final objective of this overall approach is to develop a generic model that can simulate reasonably well the occurrences of ambient O3concentrations that are dependent upon the elevation of the measurement site and the synoptic and local meteorology. Such an effort would extend the relative utility of the passive sampling data in explaining stochastic plant responses.

scholarly journals Dry deposition of nitrogen to passive samplers in grassland and forest canopies in the Central depression of southern Chile

2005 ◽  
Vol 62 (2) ◽  
Author(s):  
Roberto Godoy ◽  
Jörgen Haneke ◽  
Jeroen Staelens ◽  
Carlos Oyarzún ◽  
Leandro Paulino ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Passive Samplers ◽  
Southern Chile ◽  
Forest Canopies ◽  
Central Depression

Testing and Application of Surrogate Surfaces for Understanding Potential Gaseous Oxidized Mercury Dry Deposition

2009 ◽  
Vol 43 (16) ◽  
pp. 6235-6241 ◽  
Author(s):  
Seth N. Lyman ◽  
Mae S. Gustin ◽  
Eric M. Prestbo ◽  
Philip I. Kilner ◽  
Eric Edgerton ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Gaseous Oxidized Mercury ◽  
Surrogate Surfaces

scholarly journals Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America

2012 ◽  
Vol 12 (9) ◽  
pp. 4327-4340 ◽  
Author(s):  
L. Zhang ◽  
P. Blanchard ◽  
D. A. Gay ◽  
E. M. Prestbo ◽  
M. R. Risch ◽  
...  
Keyword(s):  
North America ◽  
Dry Deposition ◽  
Regional Scale ◽  
Elemental Mercury ◽  
Field Studies ◽  
Relative Magnitude ◽  
Point Sources ◽  
Gaseous Elemental Mercury ◽  
Surrogate Surface ◽  
Ambient Concentrations

Abstract. Dry deposition of speciated mercury, i.e., gaseous oxidized mercury (GOM), particulate-bound mercury (PBM), and gaseous elemental mercury (GEM), was estimated for the year 2008–2009 at 19 monitoring locations in eastern and central North America. Dry deposition estimates were obtained by combining monitored two- to four-hourly speciated ambient concentrations with modeled hourly dry deposition velocities (Vd) calculated using forecasted meteorology. Annual dry deposition of GOM+PBM was estimated to be in the range of 0.4 to 8.1 μg m−2 at these locations with GOM deposition being mostly five to ten times higher than PBM deposition, due to their different modeled Vd values. Net annual GEM dry deposition was estimated to be in the range of 5 to 26 μg m−2 at 18 sites and 33 μg m−2 at one site. The estimated dry deposition agrees very well with limited surrogate-surface dry deposition measurements of GOM and PBM, and also agrees with litterfall mercury measurements conducted at multiple locations in eastern and central North America. This study suggests that GEM contributes much more than GOM+PBM to the total dry deposition at the majority of the sites considered here; the only exception is at locations close to significant point sources where GEM and GOM+PBM contribute equally to the total dry deposition. The relative magnitude of the speciated dry deposition and their good comparisons with litterfall deposition suggest that mercury in litterfall originates primarily from GEM, which is consistent with the limited number of previous field studies. The study also supports previous analyses suggesting that total dry deposition of mercury is equal to, if not more important than, wet deposition of mercury on a regional scale in eastern North America.

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