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| Titel |
Characterization of the sources and processes of organic and inorganic aerosols in New York city with a high-resolution time-of-flight aerosol mass apectrometer |
| VerfasserIn |
Y.-L. Sun, Q. Zhang, J. J. Schwab, K. L. Demerjian, W.-N. Chen, M.-S. Bae, H.-M. Hung, O. Hogrefe, B. Frank, O. V. Rattigan, Y.-C. Lin |
| 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. 4 ; Nr. 11, no. 4 (2011-02-18), S.1581-1602 |
| Datensatznummer |
250009365
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| Publikation (Nr.) |
 copernicus.org/acp-11-1581-2011.pdf |
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| Zusammenfassung |
| Submicron aerosol particles (PM1) were measured in-situ using a
High-Resolution Time-of-Flight Aerosol Mass Spectrometer during the summer
2009 Field Intensive Study at Queens College in New York, NY. Organic
aerosol (OA) and sulfate are the two dominant species, accounting for 54%
and 24%, respectively, of the total PM1 mass. The average mass-based
size distribution of OA presents a small mode peaking at ~150 nm
(Dva) and an accumulation mode (~550 nm) that is internally mixed
with sulfate, nitrate, and ammonium. The diurnal cycles of both sulfate and
OA peak between 01:00–02:00 p.m. EST due to photochemical production. The
average (±σ) oxygen-to-carbon (O/C), hydrogen-to-carbon
(H/C), and nitrogen-to-carbon (N/C) ratios of OA in NYC are 0.36 (±0.09), 1.49 (±0.08), and 0.012 (±0.005), respectively,
corresponding to an average organic mass-to-carbon (OM/OC) ratio of 1.62
(±0.11). Positive matrix factorization (PMF) of the high resolution
mass spectra identified two primary OA (POA) sources, traffic and cooking,
and three secondary OA (SOA) components including a highly oxidized,
regional low-volatility oxygenated OA (LV-OOA; O/C = 0.63), a less oxidized,
semi-volatile SV-OOA (O/C = 0.38) and a unique nitrogen-enriched OA (NOA;
N/C = 0.053) characterized with prominent CxH2x + 2N+ peaks
likely from amino compounds. Our results indicate that cooking and traffic
are two distinct and mass-equivalent POA sources in NYC, together
contributing ~30% of the total OA mass during this study. The OA
composition is dominated by secondary species, especially during high PM
events. SV-OOA and LV-OOA on average account for 34% and 30%,
respectively, of the total OA mass. The chemical evolution of SOA in NYC
appears to progress with a continuous oxidation from SV-OOA to LV-OOA, which
is further supported by a gradual increase of O/C ratio and a simultaneous
decrease of H/C ratio in total OOA. Detailed analysis of NOA (5.8% of OA)
presents evidence that organic nitrogen species such as amines might have
played an important role in the atmospheric processing of OA in NYC, likely
involving both acid-base chemistry and photochemistry. In addition, analysis
of air mass trajectories and satellite imagery of aerosol optical depth
(AOD) indicates that the high potential source regions of secondary sulfate
and aged OA are mainly located in regions to the west and southwest of the
city. |
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