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| Titel |
Evaluating simulated primary anthropogenic and biomass burning organic aerosols during MILAGRO: implications for assessing treatments of secondary organic aerosols |
| VerfasserIn |
J. Fast, A. C. Aiken, J. Allan, L. Alexander, T. Campos, M. R. Canagaratna, E. Chapman, P. F. DeCarlo, B. Foy, J. Gaffney, J. Gouw, J. C. Doran, L. Emmons, A. Hodzic, S. C. Herndon, G. Huey, J. T. Jayne, J. L. Jimenez, L. Kleinman, W. Kuster, N. Marley, L. Russell, C. Ochoa, T. B. Onasch, M. Pekour, C. Song, I. M. Ulbrich, C. Warneke, D. Welsh-Bon, C. Wiedinmyer, D. R. Worsnop, X.-Y. Yu, R. Zaveri |
| 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 (2009-08-31), S.6191-6215 |
| Datensatznummer |
250007595
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| Publikation (Nr.) |
 copernicus.org/acp-9-6191-2009.pdf |
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| Zusammenfassung |
| Simulated primary organic aerosols (POA), as well as other particulates and
trace gases, in the vicinity of Mexico City are evaluated using measurements
collected during the 2006 Megacity Initiative: Local and Global Research
Observations (MILAGRO) field campaigns. Since the emission inventories,
transport, and turbulent mixing will directly affect predictions of total
organic matter and consequently total particulate matter, our objective is
to assess the uncertainties in predicted POA before testing and evaluating
the performance of secondary organic aerosol (SOA) treatments. Carbon
monoxide (CO) is well simulated on most days both over the city and
downwind, indicating that transport and mixing processes were usually
consistent with the meteorological conditions observed during MILAGRO.
Predicted and observed elemental carbon (EC) in the city was similar, but
larger errors occurred at remote locations since the overall CO/EC emission
ratios in the national emission inventory were lower than in the
metropolitan emission inventory. Components of organic aerosols derived from
Positive Matrix Factorization of data from several Aerodyne Aerosol Mass
Spectrometer instruments deployed both at ground sites and on research
aircraft are used to evaluate the model. Modeled POA was consistently lower
than the measured organic matter at the ground sites, which is consistent
with the expectation that SOA should be a large fraction of the total
organic matter mass. A much better agreement was found when modeled POA was
compared with the sum of "primary anthropogenic" and "biomass burning"
components derived from Positive Matrix Factorization (PMF) on most days,
especially at the surface sites, suggesting that the overall magnitude of
primary organic particulates released was reasonable. However, simulated POA
from anthropogenic sources was often lower than "primary anthropogenic"
components derived from PMF, consistent with two recent reports that these
emissions are underestimated. The modeled POA was greater than the total
observed organic matter when the aircraft flew directly downwind of large
fires, suggesting that biomass burning emission estimates from some large
fires may be too high. |
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