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| Titel |
Observations of dinitrogen pentoxide in both winter and summer time in Beijing, 2016 |
| VerfasserIn |
Haichao Wang, Keding Lu, Xiaorui Chen, Song Guo, Ying Liu, Franz Rohrer, Dongjie Shang, Min Shao, Sebastian Schmitt, Zhaofeng Tan, Yujue Wang, Yusheng Wu, Zhijun Wu, Jing Zheng, Limin Zeng, Andreas Wahner, Astrid Kiendler-Scharr, Mattias Hallquist, Min Hu, 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 |
250147529
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| Publikation (Nr.) |
 EGU/EGU2017-11705.pdf |
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| Zusammenfassung |
| Dinitrogen pentoxide (N2O5), as the reservoir of nitrate radical (NO3), had a significant
impact to the nighttime oxidization capacity through the fast exchange with NO3 and
accounts for the nighttime NOX removal and chlorine activation by it’s heterogeneous uptake
on the aerosols. A newly developed instrument based on the cavity enhanced absorption
spectroscopy was deployed to measure N2O5 in winter and summer time of 2016 at two
regional sites in Beijing, respectively. High concentrations of N2O5 were frequently observed
in these two seasons, the maximum mixing ratio reached up to 1.0 ppb in winter and 0.8 ppb
in summer during pollution episodes, respectively. The average mixing ratio of N2O5 in
winter was significantly higher than that in summer. In general, N2O5 began to accumulate
after sunset and reached a maximum value in a few hours later. High concentrations of
N2O5 can be sustained till the sunrise of next morning during the clean days but
decreased to zero rapidly in the first half of the night for polluted days after ambient O3
had been titrated by NO. Fast variation of N2O5 were observed from time to time
which were corresponding to the NO spikes due to the heavy duty car emissions
near the campaign sites. In addition to N2O5, a comprehensive suite of gas phase
and aerosol parameters were also determined in parallel. The uptake coefficient of
N2O5 is deduced through an iterative box model approach constrained to observed
trace gas compounds as well as aerosol surface concentrations. Empirical relations
between the uptake coefficient of N2O5 and the chemical composition of aerosols are
analyzed and compared to the findings reported in both United States and Europe. |
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