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| Titel |
A newly identified calculation discrepancy of the Sunset semi-continuous carbon analyzer |
| VerfasserIn |
G. J. Zheng, Y. Cheng, K. B. He, F. K. Duan, Y. L. Ma |
| 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 ; 7, no. 7 ; Nr. 7, no. 7 (2014-07-03), S.1969-1977 |
| Datensatznummer |
250115837
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| Publikation (Nr.) |
 copernicus.org/amt-7-1969-2014.pdf |
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| Zusammenfassung |
| The Sunset semi-continuous carbon analyzer (SCCA) is an instrument widely used
for carbonaceous aerosol measurement. Despite previous validation work, in
this study we identified a new type of SCCA calculation discrepancy caused
by the default multipoint baseline correction method. When exceeding a
certain threshold carbon load, multipoint correction could cause
significant total carbon (TC) underestimation. This calculation discrepancy
was characterized for both sucrose and ambient samples, with two protocols
based on IMPROVE (Interagency Monitoring of PROtected Visual Environments)
(i.e., IMPshort and IMPlong) and one NIOSH (National Institute for
Occupational Safety and Health)-like protocol (rtNIOSH). For ambient
samples, the IMPshort, IMPlong and rtNIOSH protocol underestimated 22,
36 and 12% of TC, respectively, with the corresponding threshold being
~ 0, 20 and 25 μgC. For sucrose, however, such
discrepancy was observed only with the IMPshort protocol, indicating the need of
more refractory SCCA calibration substance. Although the calculation
discrepancy could be largely reduced by the single-point baseline correction
method, the instrumental blanks of single-point method were higher. The
correction method proposed was to use multipoint-corrected data when below the
determined threshold, and use single-point results when beyond that
threshold. The effectiveness of this correction method was supported by
correlation with optical data. |
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