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Title:
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Continuous monitoring of atmospheric HCl, HNO2, HNO3 and SO2 bywet-annular denuder air sampling with on-line chromatographic
analysis
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Author(s):
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Published by:
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Publication date:
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ECN
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1995
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ECN report number:
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Document type:
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ECN-R--95-003
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Other
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Number of pages:
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Full text:
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26
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Download PDF
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Abstract:
An automatic system for the collection, in-line preconcentration andanalysis of acidifying atmospheric gases is described. Collection of HCl,
HNO2, HNO3 and SO2 from ambient air is carried out with an annular wet
denuder. After addition of an internal standard to the sample flow and
conductivity suppression, preconcentration of the sample flow is performed by
pumping a measured volume of the sample flow through an anion exchange
concentrator column. Following the concentration step, the anions of the
corresponding acids are analyzed by ion-chromatography with conductivity
detection. The manifold described with two sample loops and two concentrator
columns operating in parallel allows automatic collection and analysis of two
air samples per hour. A computer program has been developed for automatic
operation. It allows the system to run during extended periods without human
assistance as all the functions, including data processing, are
computer-controlled. Factors affecting the performance are reported. The
detection limits achieved are 5.4, 12.1, 12.1 and 17 ng/m3 for HCl, HNO2,
HNO3 and SO2 respectively, with relative standard deviations better than 4%
at 1-2 mug/m3. Ambient measurements for Petten, The Netherlands, are
presented showing the capability of the system for continuous monitoring of
atmospheric acidifying gases. 5 figs., 1 tab., 12 refs.
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