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Titel |
Fine aerosol bulk composition measured on WP-3D research aircraft in vicinity of the Northeastern United States – results from NEAQS |
VerfasserIn |
R. E. Peltier, A. P. Sullivan, R. J. Weber, C. A. Brock, A. G. Wollny, J. S. Holloway, J. A. Gouw, C. Warneke |
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 ; 7, no. 12 ; Nr. 7, no. 12 (2007-06-25), S.3231-3247 |
Datensatznummer |
250005090
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Publikation (Nr.) |
copernicus.org/acp-7-3231-2007.pdf |
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Zusammenfassung |
During the New England Air Quality Study (NEAQS) in the summer of 2004,
airborne measurements were made of the major inorganic ions and the
water-soluble organic carbon (WSOC) of the submicron (PM1.0) aerosol.
These and ancillary data are used to describe the overall aerosol chemical
characteristics encountered during the study. Fine particle mass was
estimated from particle volume and a calculated density based on measured
particle composition. Fine particle organic matter (OM) was estimated from
WSOC and a mass balance analysis. The aerosol over the northeastern United
States (U.S.) and Canada was predominantly sulfate and associated ammonium,
and organic components, although in unique plumes additional ionic
components were also periodically above detection limits. In power
generation regions, and especially in the Ohio River Valley region, the
aerosol tended to be predominantly sulfate (~60% μg μg−1) and apparently acidic, based on an excess of measured anions
compared to cations. In all other regions where sulfate concentrations were
lower and a smaller fraction of overall mass, the cations and anions were
balanced suggesting a more neutral aerosol. In contrast, the WSOC and
estimated OM were more spatially uniform and the fraction of OM relative to
PM mass was largely influenced by sources of sulfate. The study median OM
mass fraction was 40%. Throughout the study region, sulfate and organic
aerosol mass were highest near the surface and decreased rapidly with
increasing altitude. The relative fraction of organic mass to sulfate was
similar throughout all altitudes within the boundary layer (altitude less
than 2.5 km), but was significantly higher at altitude layers in the free
troposphere (above 2.5 km). A number of distinct biomass burning plumes from
fires in Alaska and the Yukon were periodically intercepted, mostly at
altitudes between 3 and 4 km. These plumes were associated with highest
aerosol concentrations of the study and were largely comprised of organic
aerosol components (~60%). |
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