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| Titel |
A Chemical Ionization Mass Spectrometer for ambient measurements of Ammonia |
| VerfasserIn |
D. R. Benson, A. Markovich, M. Al-Refai, S.-H. Lee |
| 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 ; 3, no. 4 ; Nr. 3, no. 4 (2010-08-19), S.1075-1087 |
| Datensatznummer |
250001221
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| Publikation (Nr.) |
 copernicus.org/amt-3-1075-2010.pdf |
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| Zusammenfassung |
| This study presents a chemical ionization mass spectrometer (CIMS) for fast
response, in-situ measurements of gas phase ammonia (NH3). The NH3
background level detected with the CIMS ranged between 0.3–1 ppbv, with
an uncertainty of 30 pptv under optimized conditions. The instrument
sensitivity varied from 4–25 Hz/pptv for >1 MHz of reagent ion signals
(protonated ethanol ions), with a 30% uncertainty estimated based on
variability in calibration signals. The CIMS detection limit for NH3
was ~60 pptv at a 1 min integration time (3 sigma). The CIMS time
response was <30 s. This new NH3-CIMS has been used for ambient
measurements in Kent, Ohio, for several weeks throughout three seasons. The
measured NH3 mixing ratios were usually at the sub-ppbv level and
higher in spring (200 ± 120 pptv) than in winter (60 ± 75 pptv) and
fall (150 ± 80 pptv). High emissions of SO2 from power plants in
this region, and thus possible high acidity of aerosol particles, may
explain these low NH3 mixing ratios in general. |
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