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@PHDTHESIS{Yu:856524,
author = {Yu, Zhujun},
title = {{C}hamber study of biogenic volatile organic compounds:
plant emission, oxidation products and their {OH}
reactivity},
volume = {436},
school = {Universität Wuppertal},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2018-05911},
isbn = {978-3-95806-356-3},
series = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {ix, 139 S.},
year = {2018},
note = {Universität Wuppertal, Diss., 2018},
abstract = {Volatile organic compounds (VOC)(Fuchs et al., 2017) are
ubiquitous in the atmosphere with an estimated atmospheric
VOC species of 10$^{4}$-10$^{5}$. Natural and anthropogenic
activities emit VOCs into the atmosphere, with about 90\% of
the global VOC emissions originating from land vegetation.
VOCs play a vital role in the global carbon budget and in
the regional formation of ozone in the troposphere. They can
also serve as a source of secondary organic aerosol (SOA).
Atmospheric lifetime of VOCs varies from minutes to years
and is predominantly determined by the reactions with
hydroxyl radical (OH), nitrate radical (NO$_{3}$), or ozone
(O$_{3}$). By atmospheric VOCs oxidation intermediate
products are formed. The detailed chemical mechanisms
involved are insufficiently known to date and need to be
understood for air quality management and climate change
predictions. OH radical as the primary oxidant in the
troposphere, initiates the degradation of nearly all types
of VOCs. The total OH reactivity is the first-order loss
rate of OH in reaction with compounds present in ambient
air, which provides an insight of the total loading of
reactive compounds in the atmosphere. Previous studies
comparing directly measured OH reactivity with that
calculated from VOC measurements often reported a "missing
OH reactivity" in the calculated one, suggesting the
existence of unquantified OH sink terms. This work presents
the emission of Biogenic VOCs (BVOCs) from 7 sets of trees
and the oxidation of VOCs in a chamber system. The focus of
this work is to investigate the atmospheric degradation of
VOCs and to improve the knowledge of the sum of reactive
trace gases involved in atmospheric processes by using the
OH reactivity parameter. A Proton-Transfer-Reaction
Time-of-Flight Mass Spectrometer (PTR-TOF-MS) was used for
real-time measurements of VOCs. Monoterpene and
sesquiterpene speciations from an offline gas-chromatograph
(GC) measurements were adopted forOHreactivity calculation
due to the reaction rate coefficient difference among
different monoterpenes and sesquiterpenes. The
intercomparison between PTR and online GC during the
selected campaigns exhibited that the measured
concentrations of the main reactants used in this study
(isoprene, monoterpenes and benzene-D$_{6}$) were linearly
correlated and differed within 15\%. The newly built plant
chamber SAPHIR-PLUS was characterized with the average BVOCs
transfer efficiency of 0.85 from inlet to outlet, and 0.8
from PLUS to the atmosphere simulation chamber SAPHIR. The
BVOCs emission pattern from $\textit{Quercus ilex}$ trees
has been determined by the use of SAPHIR-PLUS. The detected
BVOCs emissions were dominated by monoterpenes, with minor
emissions of isoprene and methanol, consistent with the
overall emission pattern typical for $\textit{Quercus ilex}$
trees in the growing season. Monoterpenes and isoprene
emissions showed to be triggered by light rather than
temperature, because these two compounds have no storage
pools in $\textit{Quercus ilex}$, their release are thus
directly connected with the photosynthesis processes in the
plant. Additionally, their emissions showed clear
exponential temperature dependence under constant light
condition, with a slope of 0.11 $\pm$ 0.02
$^{\circ}$C$^{-1}$ for monoterpenes emission. As a tracer
for leaf growth, methanol emission exhibited an abrupt
increase at the beginning of illumination. This was
explained as instantaneous release from stomata of leaves,
that stored produced methanol during the night and opened
upon light exposure. Emission of methanol increased linearly
with temperature.},
cin = {IEK-8},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {899 - ohne Topic (POF3-899)},
pid = {G:(DE-HGF)POF3-899},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2018120623},
url = {https://juser.fz-juelich.de/record/856524},
}