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Titel |
An assessment of atmospheric mercury in the Community Multiscale Air Quality (CMAQ) model at an urban site and a rural site in the Great Lakes Region of North America |
VerfasserIn |
T. Holloway, C. Voigt, J. Morton, S. N. Spak, A. P. Rutter, J. J. Schauer |
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. 15 ; Nr. 12, no. 15 (2012-08-07), S.7117-7133 |
Datensatznummer |
250011374
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Publikation (Nr.) |
copernicus.org/acp-12-7117-2012.pdf |
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Zusammenfassung |
Quantitative analysis of three atmospheric mercury species – gaseous
elemental mercury (Hg0), reactive gaseous mercury (RGHg) and
particulate mercury (PHg) – has been limited to date by lack of ambient
measurement data as well as by uncertainties in numerical models and
emission inventories. This study employs the Community Multiscale Air
Quality Model version 4.6 with mercury chemistry (CMAQ-Hg), to examine how
local emissions, meteorology, atmospheric chemistry, and deposition affect
mercury concentration and deposition the Great Lakes Region (GLR), and two
sites in Wisconsin in particular: the rural Devil's Lake site and the urban
Milwaukee site. Ambient mercury exhibits significant biases at both sites.
Hg0 is too low in CMAQ-Hg, with the model showing a 6% low bias at
the rural site and 36% low bias at the urban site. Reactive mercury (RHg = RGHg + PHg)
is over-predicted by the model, with annual average biases
>250%. Performance metrics for RHg are much worse than for
mercury wet deposition, ozone (O3), nitrogen dioxide (NO2), or
sulfur dioxide (SO2). Sensitivity simulations to isolate background
inflow from regional emissions suggests that oxidation of imported Hg0
dominates model estimates of RHg at the rural study site (91% of base
case value), and contributes 55% to the RHg at the urban site (local
emissions contribute 45%). |
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