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| Titel |
Formation kinetics and abundance of organic nitrates in α-pinene ozonolysis |
| VerfasserIn |
Thomas Berkemeier, Markus Ammann, Ulrich Pöschl, Manabu Shiraiwa |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135985
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| Publikation (Nr.) |
 EGU/EGU2016-16922.pdf |
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| Zusammenfassung |
| Formation of organic nitrates affects the total atmospheric budget of oxidized nitrogen (NOy)
and alters the total aerosol mass yield from secondary sources. We investigated the formation
of organic nitrate species during ozonolysis of α-pinene and subsequent formation
of secondary organic aerosols (SOA) using the short-lived radioactive tracer 13N
inside an aerosol flow reactor (Ammann et al., 2001). The results represent direct
measurements of the organic nitrate content of α-pinene secondary aerosol and give
insight into the kinetics of organic nitrate formation. Organic nitrates constituted up
to 40 % of aerosol mass with a pronounced influence during the initial period of
particle growth. Kinetic modelling, as well as additional experiments using OH
scavengers and UV irradiation, suggests that organic peroxy radicals (RO2) from the
reaction of α-pinene with secondarily produced OH are important intermediates in the
organic nitrate formation process. Direct oxidation of α-pinene by NO3 was found
to be a less efficient pathway for formation of particle phase nitrate. The organic
nitrate content decreased very slightly with an increase of relative humidity on the
experimental time scale. The experiments show a tight correlation between organic
nitrate content and SOA number concentrations, implying that organic nitrates
play an important role in nucleation and growth of nanoparticles. Since present in
large amounts in organic aerosol, organic nitrates deposited in the lung might have
implications for human health as they release nitric acid upon hydrolysis, especially
in regions influenced by urban pollution and large sources of monoterpene SOA
precursors.
References
Ammann et al. (2001) Radiochimica Acta 89, 831. |
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