Thesis
Field measurements of mercury deposition in Pullman and Puyallup, WA
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/106107
Abstract
The overarching objective of this study was to evaluate mercury deposition in two locations in Washington State: Pullman, WA in the rural east side of the state and Puyallup, WA on the populated west side of the state. Measurements were made from late summer to early fall of 2011 using a wet surface sampler for dry deposition and a precipitation collector for wet deposition. Puyallup was hypothesized to have higher rates of mercury deposition due to its proximity to substantial anthropogenic sources including intensive urban activities and atmospheric influxes from Asia. Dry deposition fluxes were 55.0 ± 34.5 ng/m2 /d (average plus/minus standard deviation; n = 4) in Pullman and 29.7 ± 7.0 ng/m2 /d in Puyallup (n = 6). Wet deposition fluxes were 166 ± 112 ng/m2 /d (n = 4) in Pullman and 25.3 ± 5.1 ng/m2 /d in Puyallup (n = 3). In contrast to our hypothesis, deposition levels were higher in Pullman, particularly during one dry deposition sampling event in late August (103 ng/m2 /d) and three wet deposition sampling events in late June (303 ng/m2 /d) and mid July (112 and 206 ng/m2 /d). The high deposition rates in Pullman were likely a result of local anthropogenic activities that enhance mercury depositing including summertime agricultural harvesting and field burning. Field results were also compared to mercury depositional fluxes predicted by the numerical air quality forecast system AIRPACT-3. Modeled deposition results were lower than measured deposition results for both Pullman and Puyallup during the comparable sampling duration. A likely reason for lower modeled deposition rates compared to measured deposition rates is the lack of agricultural field burning emissions data available for the AIRPACT-3 model. This study, while limited in its scope, adds to the data set of mercury deposition in Washington, which has little data for the east side of the state and mainly consists of wet deposition on the west side of the state.
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Details
- Title
- Field measurements of mercury deposition in Pullman and Puyallup, WA
- Creators
- Lanka DeSilva
- Contributors
- Marc W. Beutel (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525116101842
- Language
- English
- Resource Type
- Thesis