 |
| Titel |
Reactive uptake of ammonia to secondary organic aerosols: kinetics of organonitrogen formation |
| VerfasserIn |
Y. Liu, J. Liggio, R. Staebler, S.-M. Li |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 23 ; Nr. 15, no. 23 (2015-12-09), S.13569-13584 |
| Datensatznummer |
250120211
|
| Publikation (Nr.) |
 copernicus.org/acp-15-13569-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| As a class of brown carbon, organonitrogen compounds originating from the
heterogeneous uptake of NH3 by secondary organic aerosol (SOA) have
received significant attention recently. In the current work, particulate
organonitrogen formation during the ozonolysis of α-pinene and the OH
oxidation of m-xylene in the presence of ammonia (34–125 ppb) was studied
in a smog chamber equipped with a high resolution time-of-flight aerosol mass
spectrometer and a quantum cascade laser instrument. A large diversity of
nitrogen-containing organic (NOC) fragments was observed which were
consistent with the reactions between ammonia and carbonyl-containing SOA.
Ammonia uptake coefficients onto SOA which led to organonitrogen compounds
were reported for the first time, and were in the range of ∼
10-3–10−2, decreasing significantly to < 10-5 after
6 h of reaction. At the end of experiments (~ 6 h) the NOC mass
contributed 8.9 ± 1.7 and 31.5 ± 4.4 wt % to the total
α-pinene- and m-xylene-derived SOA, respectively, and
4–15 wt % of the total nitrogen in the system. Uptake coefficients were
also found to be positively correlated with particle acidity and negatively
correlated with NH3 concentration, indicating that heterogeneous
reactions were responsible for the observed NOC mass, possibly limited by
liquid phase diffusion. Under these conditions, the data also indicate that
the formation of NOC can compete kinetically with inorganic acid
neutralization. The formation of NOC in this study suggests that a
significant portion of the ambient particle associated N may be derived from
NH3 heterogeneous reactions with SOA. NOC from such a mechanism may be
an important and unaccounted for source of PM associated nitrogen. This
mechanism may also contribute to the medium or long-range transport and
wet/dry deposition of atmospheric nitrogen. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|