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| Titel |
COMPASS – COMparative Particle formation in the Atmosphere using portable Simulation chamber Study techniques |
| VerfasserIn |
B. Bonn, S. Sun, W. Haunold, R. Sitals, E. van Beesel, L. dos Santos, B. Nillius, S. Jacobi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 12 ; Nr. 6, no. 12 (2013-12-09), S.3407-3423 |
| Datensatznummer |
250085128
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| Publikation (Nr.) |
 copernicus.org/amt-6-3407-2013.pdf |
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| Zusammenfassung |
| In this study we report the set-up of a novel twin chamber technique that
uses the comparative method and establishes an appropriate connection of
atmospheric and laboratory methods to broaden the tools for investigations.
It is designed to study the impact of certain parameters and gases on ambient
processes, such as particle formation online, and can be applied in a large
variety of conditions. The characterisation of both chambers proved that both
chambers operate identically, with a residence time xT
(COMPASS1) = 26.5 ± 0.3 min and xT (COMPASS2) = 26.6 ±
0.4 min, at a typical flow rate of 15 L min−1 and a gas leak rate of (1.6 ±
0.8) × 10−5 s−1. Particle loss rates were found to be
larger (due to the particles' stickiness to the chamber walls), with an extrapolated maximum of
1.8 × 10−3 s−1 at 1 nm, i.e. a hundredfold of the gas leak
rate. This latter value is associated with sticky non-volatile gaseous
compounds, too. Comparison measurement showed no significant differences.
Therefore operation under atmospheric conditions is trustworthy. To indicate
the applicability and the benefit of the system, a set of experiments was
conducted under different conditions, i.e. urban and remote, enhanced ozone and
terpenes as well as reduced sunlight. In order to do so, an ozone lamp was
applied to enhance ozone in one of two chambers; the measurement chamber was
protected from radiation by a first-aid cover and volatile
organic compounds (VOCs) were added using a
small additional flow and a temperature-controlled oven. During the elevated
ozone period, ambient particle number and volume increased substantially at
urban and remote conditions, but by a different intensity. Protection of solar
radiation displayed a clear negative effect on particle number, while terpene
addition did cause a distinct daily pattern. E.g. adding β pinene
particle number concentration rose by 13% maximum at noontime, while no
significant effect was observable during darkness. Therefore, the system is a
useful tool for investigating local precursors and the details of ambient particle
formation at surface locations as well as potential future feedback
processes. |
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