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Titel |
Observation and modelling of the OH, HO2 and RO2 radicals at a
suburban site of Beijing (Huairou) in winter 2016 |
VerfasserIn |
Zhaofeng Tan, Keding Lu, Xuefei Ma, Bohn Birger, Sebastian Broch, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, Xin Li, Yuhan Liu, Anna Novelli, Franz Rohrer, Min Shao, Haichao Wang, Yusheng Wu, Limin Zeng, Astrid Kiendler-Scharr, Andreas Wahner, Yuanhang Zhang |
Konferenz |
EGU General Assembly 2017
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Medientyp |
Artikel
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Sprache |
en
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 19 (2017) |
Datensatznummer |
250146953
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Publikation (Nr.) |
EGU/EGU2017-11027.pdf |
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Zusammenfassung |
A comprehensive field campaign was carried out in winter 2016 in Huairou, a small town
located 60 km northeast of Beijing downtown. Concentrations of OH, HO2and RO2 radicals
were measured by a laser induced fluorescence instrument. Radical concentrations were
smaller than during summer because of reduced solar radiation. Maximum hourly averaged
OH, HO2 and RO2 radical concentrations were (3±2)×106cm−3, (8±6)×107 cm−3 and
(7±5)×107 cm−3, respectively. Chemical modulation measurements were applied on a few
days showing no significant OH interference for different chemical conditions. HONO and
HCHO photolysis were found to be the most important primary source of ROx
radicals. OH reactivity, the inverse of the OH radical lifetime, was also measured by a
laser-photolysis and laser induced fluorescence instrument. In general, CO and NOx were the
dominated OH reactants which contributed more than half of the total OH reactivity. The
relative high OH concentrations in polluted episode enabled a fast oxidation of fresh
emitted pollutants and the formation of secondary products. The observed radical
concentrations were compared with the results from a chemical box model. The model is
capable of reproducing radical concentrations in the moderate NOx conditions but
has difficulty in both the low and high NOx regimes. The underestimation of RO2
radical concentrations in the high NOx conditions indicate a missing RO2 source. |
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