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| Titel |
Inverse modeling and mapping US air quality influences of inorganic PM2.5 precursor emissions using the adjoint of GEOS-Chem |
| VerfasserIn |
D. K. Henze, J. H. Seinfeld, D. T. Shindell  |
| 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 ; 9, no. 16 ; Nr. 9, no. 16 (2009-08-19), S.5877-5903 |
| Datensatznummer |
250007575
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| Publikation (Nr.) |
 copernicus.org/acp-9-5877-2009.pdf |
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| Zusammenfassung |
| Influences of specific sources of inorganic PM2.5 on peak and ambient
aerosol concentrations in the US are evaluated using a combination of inverse
modeling and sensitivity analysis. First, sulfate and nitrate aerosol
measurements from the IMPROVE network are assimilated using the
four-dimensional variational (4D-Var) method into the GEOS-Chem chemical
transport model in order to constrain emissions estimates in four separate
month-long inversions (one per season). Of the precursor emissions, these
observations primarily constrain ammonia (NH3). While the net result is a
decrease in estimated US~NH3 emissions relative to the original inventory,
there is considerable variability in adjustments made to NH3 emissions in
different locations, seasons and source sectors, such as focused decreases in
the midwest during July, broad decreases throughout the US~in January,
increases in eastern coastal areas in April, and an effective redistribution
of emissions from natural to anthropogenic sources. Implementing these
constrained emissions, the adjoint model is applied to quantify the
influences of emissions on representative PM2.5 air quality metrics
within the US. The resulting sensitivity maps display a wide range of
spatial, sectoral and seasonal variability in the susceptibility of the air
quality metrics to absolute emissions changes and the effectiveness of
incremental emissions controls of specific source sectors. NH3 emissions
near sources of sulfur oxides (SOx) are estimated to most influence
peak inorganic PM2.5 levels in the East; thus, the most effective
controls of NH3 emissions are often disjoint from locations of peak NH3
emissions. Controls of emissions from industrial sectors of SOx and
NOx are estimated to be more effective than surface emissions, and
changes to NH3 emissions in regions dominated by natural sources are
disproportionately more effective than regions dominated by anthropogenic
sources. NOx controls are most effective in northern states in
October; in January, SOx controls may be counterproductive. When
considering ambient inorganic PM2.5 concentrations, intercontinental
influences are small, though transboundary influences within North America
are significant, with SOx emissions from surface sources in Mexico
contributing almost a fourth of the total influence from this sector. |
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