 |
| Titel |
Patterns of mercury dispersion from local and regional emission sources, rural Central Wisconsin, USA |
| VerfasserIn |
Allan Kolker, M. L. Olson, D. P. Krabbenhoft, M. T. Tate, M. A. Engle |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 10 ; Nr. 10, no. 10 (2010-05-17), S.4467-4476 |
| Datensatznummer |
250008455
|
| Publikation (Nr.) |
 copernicus.org/acp-10-4467-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Simultaneous real-time changes in mercury (Hg) speciation- reactive gaseous
Hg (RGM), elemental Hg (Hg°), and fine particulate Hg (Hg-PM2.5),
were determined from June to November, 2007, in ambient air at three
locations in rural Central Wisconsin. Known Hg emission sources within the
airshed of the monitoring sites include: 1) a 1114 megawatt (MW) coal-fired
electric utility generating station; 2) a Hg-bed chlor-alkali plant; and 3) a
smaller (465 MW) coal-burning electric utility. Monitoring sites, showing
sporadic elevation of Hg°, Hg-PM2.5, and RGM were positioned at
distances of 25, 50 and 100 km northward of the larger electric utility.
Median concentrations of Hg°, Hg-PM2.5, and RGM were
1.3–1.4 ng m−3, 2.6–5.0 pg m−3, and 0.6–0.8 pg m−3,
respectively. A series of RGM events were recorded at each site. The largest,
on 23 September, occurred under prevailing southerly winds, with a maximum
RGM value (56.8 pg m-3) measured at the 100 km site, and
corresponding elevated SO2 (10.4 ppbv; measured at 50 km site). The
finding that RGM, Hg°, and Hg-PM2.5 are not always highest at the
25 km site, closest to the large generating station, contradicts the idea
that RGM decreases with distance from a large point source. This may be
explained if: 1) the 100 km site was influenced by emissions from the
chlor-alkali facility or by RGM from regional urban sources; 2) the emission
stack height of the larger power plant promoted plume transport at an
elevation where the Hg is carried over the closest site; or 3) RGM was being
generated in the plume through oxidation of Hg°. Operational changes
at each emitter since 2007 should reduce their Hg output, potentially
allowing quantification of the environmental benefit in future studies. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|