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| Titel |
Identification of potential regional sources of atmospheric total gaseous mercury in Windsor, Ontario, Canada using hybrid receptor modeling |
| VerfasserIn |
X. Xu, U. S. Akhtar |
| 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 ; 10, no. 15 ; Nr. 10, no. 15 (2010-08-03), S.7073-7083 |
| Datensatznummer |
250008671
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| Publikation (Nr.) |
 copernicus.org/acp-10-7073-2010.pdf |
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| Zusammenfassung |
Windsor (Ontario, Canada) experiences trans-boundary air pollution as it is
located on the border immediately downwind of industrialized regions of the
United States of America. A study was conducted in 2007 to identify the
potential regional sources of total gaseous mercury (TGM) and investigate
the effects of regional sources and other factors on seasonal variability of
TGM concentrations in Windsor.
TGM concentration was measured at the University of Windsor campus using a
Tekran® 2537A Hg vapour analyzer. An annual mean of
2.02±1.63 ng/m3 was observed in 2007. The average TGM concentration
was high in the summer (2.48±2.68 ng/m3) and winter
(2.17±2.01 ng/m3), compared to spring (1.88±0.78 ng/m3) and fall
(1.76±0.58 ng/m3). Hybrid receptor modeling potential source
contribution function (PSCF) was used by incorporating 72-h backward
trajectories and measurements of TGM in Windsor. The results of PSCF were
analyzed in conjunction with the Hg emissions inventory of North America (by
state/province) to identify regions affecting Windsor. In addition to annual
modeling, seasonal PSCF modeling was also conducted. The potential source
region was identified between 24–61° N and 51–143° W. Annual PSCF
modeling identified major sources southwest of Windsor, stretching from Ohio
to Texas. The emissions inventory also supported the findings, as Hg
emissions were high in those regions. Results of seasonal PSCF modeling were
analyzed to find the combined effects of regional sources, meteorological
conditions, and surface re-emissions, on seasonal variability of Hg
concentrations. It was found that the summer and winter highs of atmospheric
Hg can be attributed to areas where large numbers of coal fired power plants
are located in the USA. Weak atmospheric dispersion due to low winds and
high re-emission from surfaces due to higher temperatures also contributed
to high concentrations in the summer. In the winter, the atmospheric removal
of Hg was slow, but strong winds led to more dispersion, resulting in lower
concentrations than the summer. Future studies could use smaller grid sizes
and refined emission inventories, for more accurate analysis of
source-receptor relationship of atmospheric Hg. |
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