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| Titel |
Observations of ambient monoterpenes at a costal site in the East Mediterranean |
| VerfasserIn |
Evaggelia Tzitzikalaki, Nikolaos Kalivitis, Giorgos Kouvarakis, Maria Kanakidou, Nikolaos Mihalopoulos |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250113131
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| Publikation (Nr.) |
 EGU/EGU2015-13326.pdf |
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| Zusammenfassung |
| Observations of ambient monoterpenes at a costal site in the East Mediterranean
Biogenic Volatile Organic Compounds (BVOCs) affect the oxidizing capacity of the
atmosphere since they react with hydroxyl radicals, nitrate radicals and ozone, and
participate in ozone formation in the presence of sufficient amounts of nitrogen oxides.
Moreover, BVOC oxidation products contribute to new particle formation and growth
processes. While isoprene is emitted in the largest amount among BVOCs into
the atmosphere, monoterpenes are also important for atmospheric chemistry. Tree
species are responsible of the most BVOC emissions to the atmosphere but little is
known about the contribution of shrub and long-range transport to the ambient
BVOC concentrations. In the Mediterranean region monoterpene measurements are
scarce and are limited in temporal and ecosystem coverage (forested areas). The
present study presents long- term measurements of monoterpenes at a remote coastal
site without tree vegetation under typical phrygana vegetation of Crete island in
Greece.
Measurements took place (35Ë 20´ N, 25Ë 40´ E, 250m a.s.l) on the north east side of
the island of Crete at the Finokalia monitoring station of the University of Crete
(http://finokalia.chemistry.uoc.gr). Two intensive campaigns took place, one during spring
(13/03-08/04/2014) and one during summer(19/06 – 04/08/2014). During each campaign
diurnal cycles were measured collecting 9 samples per day(every two hours). In addition, one
diurnal cycle per week has been measured since 13/10/2014. Off-line sampling took place in
adsorption tubes, using stainless steel cartridges filled with Tenax TA for one hour at 200
ml/min flow rate. Samples were stored at 40C and analyzed within two days. The
samples were after desorption by a Thermal Desorber were analyzed by a GC-FID
system.
The most abundant monoterpenes were found to be δ3-carene and limonene.Highest
concentrations were observed during autumn when a clear diurnal cycle has been seen with
maximum for both δ3-carene and limonene at late afternoon. During summer, no clear
diurnal variance was observed while in spring the cycle was weaker. The results are analyzed
together with new particle formation observations at the Finokalia station to estimate possible
links of BVOCs to the formation and growth processes of atmospheric particles in the
area. |
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