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| Titel |
Organic nitrogen in PM2.5 aerosol at a forest site in the Southeast US |
| VerfasserIn |
M. Lin, J. Walker, C. Geron, A. Khlystov |
| 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 ; 10, no. 5 ; Nr. 10, no. 5 (2010-03-01), S.2145-2157 |
| Datensatznummer |
250008161
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| Publikation (Nr.) |
 copernicus.org/acp-10-2145-2010.pdf |
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| Zusammenfassung |
There is growing evidence that organo-nitrogen compounds may constitute a
significant fraction of the aerosol nitrogen (N) budget. However, very little
is known about the abundance and origin of this aerosol fraction. In this
study, the concentration of organic nitrogen (ON) and major inorganic ions in
PM2.5 aerosol were measured at the Duke Forest Research Facility
near Chapel Hill, NC, during January and June of 2007. A novel on-line
instrument was used, which is based on the Steam Jet Aerosol Collector (SJAC)
coupled to an on-line total carbon/total nitrogen analyzer and two on-line
ion chromatographs. The concentration of ON was determined by tracking the
difference in concentrations of total nitrogen and of inorganic nitrogen
(determined as the sum of N-ammonium and N-nitrate). The time resolution of
the instrument was 30 min with a detection limit for major aerosol
components of ~0.1 μg m−3.
Nitrogen in organic compounds contributed ~33% on average to the total
nitrogen concentration in PM2.5, illustrating the importance of
this aerosol component. Absolute concentrations of ON, however, were
relatively low (<1.0 μg m−3) with an average of
0.16 μg m−3. The absolute and relative contribution of ON to
the total aerosol nitrogen budget was practically the same in January and
June. In January, the concentration of ON tended to be higher during the
night and early morning, while in June it tended to be higher during the late
afternoon and evening. Back-trajectories and correlation with wind direction
indicate that higher concentrations of ON occur in air masses originating
over the continental US, while marine air masses are characterized by lower
ON concentrations. The data presented in this study suggests that ON has a
variety of sources, which are very difficult to quantify without information
on chemical composition of this important aerosol fraction. |
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