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| Titel |
The 2005 Study of Organic Aerosols at Riverside (SOAR-1): instrumental intercomparisons and fine particle composition |
| VerfasserIn |
K. S. Docherty, A. C. Aiken, J. A. Huffman, I. M. Ulbrich, P. F. DeCarlo, D. Sueper, D. R. Worsnop, D. C. Snyder, R. E. Peltier, R. J. Weber, B. D. Grover, D. J. Eatough, B. J. Williams, A. H. Goldstein, P. J. Ziemann, J. L. Jimenez |
| 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 ; 11, no. 23 ; Nr. 11, no. 23 (2011-12-12), S.12387-12420 |
| Datensatznummer |
250010256
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| Publikation (Nr.) |
 copernicus.org/acp-11-12387-2011.pdf |
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| Zusammenfassung |
| Multiple state-of-the-art instruments sampled ambient aerosol in Riverside,
California during the 2005 Study of Organic Aerosols at Riverside (SOAR) to
investigate the chemical composition and potential sources of fine particles
(PMf) in the inland region of Southern California. In this paper, we
briefly summarize the spatial, meteorological and gas-phase conditions
during SOAR-1 (15 July–15 August), provide detailed intercomparisons of
high-resolution aerosol mass spectrometer (HR-AMS) measurements against
complementary measurements, and report the average composition of PMf
including the composition of the organic fraction measured by the HR-AMS.
Daily meteorology and gas-phase species concentrations were highly
consistent, displaying clear diurnal cycles and weekday/weekend contrast.
HR-AMS measurements of non-refractory submicron (NR-PM1) mass are consistent and
highly correlated with those from a filter dynamics measurement system
tapered-element oscillating microbalance (TEOM), while the correlation between
HR-AMS and heated TEOM measurements is lower due to loss of high volatility
species including ammonium nitrate from the heated TEOM. Speciated HR-AMS
measurements are also consistent with complementary measurements as well as
with measurements from a collocated compact AMS while HR-AMS OC is similar
to standard semi-continuous Sunset measurements within the combined
uncertainties of both instruments. A correction intended to account for the
loss of semi-volatile OC from the Sunset, however, yields measurements ~30% higher than either HR-AMS or standard Sunset measurements. On
average, organic aerosol (OA) was the single largest component of PMf.
OA composition was investigated using both elemental analysis and positive
matrix factorization (PMF) of HR-AMS OA spectra. Oxygen is the main
heteroatom during SOAR-1, with O/C exhibiting a diurnal minimum of 0.28
during the morning rush hour and maximum of 0.42 during the afternoon. O/C
is broadly anti-correlated with H/C, while N/C and S/C (excluding
organonitrate (ON) and organosulfate (OS) functionalities) are far lower
than O/C at about 0.015 and ~0.001, respectively. When ON and OS
estimates are included O/C, N/C, and S/C increase by factors of 1.21, 2, and
30, respectively, while H/C changes are insignificant. The increase in these
ratios implies that ON accounts for ~1/2 of the organic nitrogen while
OS dominate organic sulfur at this location. Accounting for the estimated ON
and OS also improves the agreement between anions and cations measured by
HR-AMS by ~8%, while amines have only a very small impact (1%)
on this balance. Finally, a number of primary and secondary OA components
were resolved by PMF. Among these a hydrocarbon-like OA and two minor, local
OA components, one of which was associated with amines, were attributed to
primary emissions and contributed a minor fraction (~20%) of OA
mass. The remaining OA mass was attributed to a number of secondary oxidized
OA (OOA) components including the previously-identified low-volatility and
semi-volatile OOA components. In addition, we also report
for the first time the presence of two additional OOA components. |
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