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| Titel |
Investigating sources of gaseous oxidized mercury in dry deposition at three sites across Florida, USA |
| VerfasserIn |
M. Sexauer Gustin, P. S. Weiss-Penzias, C. Peterson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 19 ; Nr. 12, no. 19 (2012-10-11), S.9201-9219 |
| Datensatznummer |
250011502
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| Publikation (Nr.) |
 copernicus.org/acp-12-9201-2012.pdf |
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| Zusammenfassung |
| During 2009–2010, the State of Florida established a series of air quality
monitoring stations to collect data for development of a statewide total
maximum daily load (TMDL) for mercury (Hg). At three of these sites, located
near Ft. Lauderdale (DVE), Pensacola (OLF), and Tampa Bay (TPA), passive
samplers for the measurement of air Hg concentrations and surrogate surfaces
for measurement of Hg dry deposition were deployed. While it is known that Hg
in wet deposition in Florida is high compared to the rest of the United
States, there is little information on Hg dry deposition. The objectives of
the work were to: (1) investigate the utility of passive sampling systems for
Hg in an area with low and consistent air concentrations as measured by the
Tekran® mercury measurement system, (2) estimate
dry deposition of gaseous oxidized Hg, and (3) investigate potential sources.
This paper focuses on Objective 3. All sites were situated within 15 km of
1000 MW electricity generating plants (EGPs) and major highways. Bi-weekly
dry deposition and passive sampler Hg uptake were not directly correlated
with the automated Tekran® system measurements,
and there was limited agreement between these systems for periods of high
deposition. Using diel, biweekly, and seasonal Hg observations, and ancillary
data collected at each site, the potential sources of Hg deposited to
surrogate surfaces were investigated. With this information, we conclude that
there are three major processes/sources contributing to Hg dry deposition in
Florida, with these varying as a function of location and time of year. These
include: (1) in situ oxidation of locally and regionally derived Hg
facilitated by mobile source emissions, (2) indirect and direct inputs of Hg
from local EGPs, and (3) direct input of Hg associated with long range
transport of air from the northeastern United States. Based on data collected
with the surrogate surface sampling system, natural background dry deposition
for Florida is estimated to be 0.03 ng m−2 h−1. Deposition
associated with mobile sources is 0.10 ng m−2 h−1 at TPA and DVE,
and 0.03 ng m−2 h−1 at OLF. Long range transport contributes
0.8 ng m−2 h−1 in the spring. At DVE
~0.10 ng m−2 h−1 is contributed directly or indirectly from
local point sources. We also suggest based on the data collected with the
Tekran® and passive sampling systems that
different chemical forms of GOM are associated with each of these sources. |
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