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| Titel |
Estimation of speciated and total mercury dry deposition at monitoring locations in eastern and central North America |
| VerfasserIn |
L. Zhang, P. Blanchard, D. A. Gay, E. M. Prestbo, M. R. Risch, D. Johnson, J. Narayan, R. Zsolway, T. M. Holsen, E. K. Miller, M. S. Castro, J. A. Graydon, V. L. St. Louis, J. Dalziel |
| 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. 9 ; Nr. 12, no. 9 (2012-05-15), S.4327-4340 |
| Datensatznummer |
250011137
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| Publikation (Nr.) |
 copernicus.org/acp-12-4327-2012.pdf |
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| Zusammenfassung |
| 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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