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| Titel |
The composition of nucleation and Aitken modes particles during coastal nucleation events: evidence for marine secondary organic contribution |
| VerfasserIn |
P. Vaattovaara, P. E. Huttunen, Y. J. Yoon, J. Joutsensaari, K. E. J. Lehtinen, C. D. O'Dowd, A. Laaksonen |
| 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 ; 6, no. 12 ; Nr. 6, no. 12 (2006-10-12), S.4601-4616 |
| Datensatznummer |
250004140
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| Publikation (Nr.) |
 copernicus.org/acp-6-4601-2006.pdf |
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| Zusammenfassung |
| Newly-formed nanometer-sized particles have been observed at coastal and
marine environments world wide. Organic species have so far not been
detected in those newly-formed nucleation mode particles. In this study, we
applied the ultrafine organic tandem differential mobility analyzer method
to study the possible existence of an organic fraction in recently formed
coastal nucleation mode particles (d<20 nm) at the Mace Head research
station. Furthermore, effects of those nucleation events on potential cloud
condensation nuclei were studied. The coastal events were typical for the
Mace Head region and they occurred at low tide conditions during efficient
solar radiation and enhanced biological activity in spring 2002.
Additionally, a pulse height analyzer ultrafine condensation particle
counter technique was used to study the composition of newly-formed
particles formed in low tide conditions during a lower biological activity
in October 2002. The overall results of the ultrafine organic tandem
differential mobility analyzer and the pulse height analyzer ultrafine
condensation particle counter measurements indicate that those
coastally/marinely formed nucleation mode particles include a remarkable
fraction of secondary organic products, beside iodine oxides, which are
likely to be responsible for the nucleation. During clean marine air mass
conditions, the origin of those secondary organic oxidation compounds can be
related to marine coast and open ocean biota and thus a major fraction of
the organics may originate from biosynthetic production of alkenes such as
isoprene and their oxidation driven by iodine radicals, hydroxyl radicals,
acid catalysis, and ozone during efficient solar radiation. During modified
marine conditions, also anthropogenic secondary organic compounds may
contribute to the nucleation mode organic mass, in addition to biogenic
secondary organic compounds. Thus, the ultrafine organic tandem differential
mobility analyzer results suggest that the secondary organic compounds may,
in addition to being significant contributors to the nucleation mode
processes, accelerate the growth of freshly nucleated particles and increase
their survival probability to cloud condensation nuclei and even larger
radiatively active particle sizes. The results give new insights to the
marine/coastal particle formation, growth, and properties. The marine biota
driven secondary organic contributions to marine/coastal particle formation
and composition can be anticipated in other species specific biologically
active oceans and fresh-waters areas around the world and thus, they may be
significant also to the global radiative bugdet, atmosphere-biosphere
feedbacks, and climate change. |
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