Titel
Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions
Autor*in
A. P. Praplan
Department of Physics, University of Helsinki
S. Schobesberger
Department of Physics, University of Helsinki
F. Bianchi
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute
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Abstract
This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1) pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH) scavenger) and (2) OH oxidation (initiated by nitrous acid (HONO) photolysis by ultraviolet light) in the absence of ozone.
We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF) mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate). Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition of oxidation products and their clustering behaviour, several instruments must be used. We compare oxidation products containing 10 and 20 carbon atoms and show that highly oxidised organic compounds are formed in the early stages of the oxidation.
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
Atmospheric Chemistry and Physics
Band
15
Ausgabe
8
Seitenanfang
4145
Seitenende
4159
Publication
Copernicus GmbH
Erscheinungsdatum
2015
Zugänglichkeit
Rechte
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