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Annular denuders for use in global climate and stratospheric measurements of acidic gases and particlesMeasurements of acidic and basic gases that coexist with fine particle (less than 2.5 micron) may be useful for determining the impact of these species on global climate changes and determining species that influence stratospheric ozone levels. Annular denuders are well suited for this purpose. A new concentric annular denuder system, consisting of a three channel denuder, a Teflon coated cyclone preseparator, and a multistage filter pack was developed, evaluated, and shown to provide reliable atmospheric measurements of SO2, HNO2, HNO3, NH3, SO4(=), NH4(+), NO3(-), and H(+). For example, the precision of the annular denuder for the ambient measurements of HNO3 and nitrates at concentrations between 0.1 to 3 microgram/cu m was + or - 12 and 16 pct., respectively. The 120 x 25 mm three channel denuder is encased in a stainless steel sheath and has annular spaces that are 1 mm wide. This design was shown to have nearly identical capacity for removal of SO2 as conventional 210 x 25 mm single channel denuder configurations. The cyclone preseparator was designed and tested to have a D sub 50 cutoff diameter of 2.5 micron and minimal retention of HNO3.
Document ID
19910023217
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Stevens, Robert K.
(Environmental Protection Agency Research Triangle Park, NC, United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1991
Publication Information
Publication: NASA. Ames Research Center, International Workshop on Stratospheric Aerosols: Measurements, Properties, and Effects
Subject Category
Geophysics
Accession Number
91N32531
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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