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@PHDTHESIS{Kaminski:151374,
author = {Kaminski, Martin},
title = {{U}ntersuchung des photochemischen {T}erpenoidabbaus in der
{A}tmosphärensimulationskammer {SAPHIR}},
volume = {218},
school = {Universität Köln},
type = {Dr.},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2014-01343},
isbn = {987-3-89336-967-6},
series = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {148 S.},
year = {2014},
note = {Universität Köln, Diss., 2014},
abstract = {The hydroxyl radical (OH) is the main oxidation agent in
the atmosphere during daytime. Recent field campaigns
studying the radical chemistry in forested areas showed
large discrepancies between measured and modeled OH
concentration at low NO$_{x}$ conditions and a VOC dominated
OH reactivity k(OH) (Hofzumahaus et al., 2009; Lelieveld et
al., 2008). These observations were only partially explained
by the evidence for new efficient hydroxyl radical
regeneration pathways in the isoprene oxidation mechanism
(Fuchs et al., 2013; Whalley et al., 2011). So it is likely
that other VOC species are also capable of additional OH
recycling. Beside isoprene monoterpenes and
2-methyl-3-buten-2-ol (MBO) belong to the volatile organic
compound (VOC) species with the highest global emission
rates. Due to their high reactivity towards OH, monoterpenes
and MBO can dominate the radical chemistry of the atmosphere
in forested areas under certain conditions (Kim et al.,
2013). In the present study the photochemical degradation
mechanism of $\alpha$-pinene, $\beta$-pinene, limonene,
myrcene and MBO was investigated in the atmosphere
simulation chamber SAPHIR. The focus of this study was in
particular on the investigation of the radical budget in the
degradation process. The photochemical degradation of the
five terpenoids was studied in a dedicated series of
experiments in the years 2012 and 2013. The SAPHIR chamber
was equipped with instrumentation to measure all important
OH precursors (O$_{3}$, HONO, HCHO), the parent VOC and its
main oxidation products, radicals (OH, HO$_{2}$, RO$_{2}$),
the total OH reactivity, and photolysis frequencies to
investigate the radical budget in the chamber. All
experiments were carried out under low NOx conditions (≤
2ppb) and atmospheric terpenoid concentrations (≤ 5ppb)
with and without the addition of ozone. The intercomparison
of the measured time series of the atmospheric trace gases
with simulations using the atmospheric box model Master
Chemical Mechanism (MCM) 3.2 showed that the MBO experiments
could be described well by the MCM. In contrast to MBO the
measured OH and HO$_{2}$ concentrations in the simulations
of the $\alpha$-pinene, $\beta$- pinene and limonene
experiments were systematically underestimated. In addition
the measured k(OH) was overestimated increasingly by the MCM
model after VOC injection in the atmosphere simulation
chamber. A sensitivity study showed that this overestimation
is related to the product spectrum assumed in the MCM model.
Despite adjusting the modelled k(OH) to the measured values
the measured OH and HO2 concentrations were still
underestimated by the model. Model sensitivity studies on
additional OH [...]},
keywords = {Dissertation (GND)},
cin = {IEK-8},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {233 - Trace gas and aerosol processes in the troposphere
(POF2-233)},
pid = {G:(DE-HGF)POF2-233},
typ = {PUB:(DE-HGF)11},
url = {https://juser.fz-juelich.de/record/151374},
}