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Investigation of water vapor effects on the detection of nitric acid vapor with the tungstic acid technique

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dc.contributor.authorMarinaro, Ralph Michaelen
dc.contributor.committeechairHughes, John M.en
dc.contributor.committeememberBoardman, Gregoryen
dc.contributor.committeememberChevone, Boris I.en
dc.contributor.committeememberWightman, James P.en
dc.contributor.committeememberConn, W. Daviden
dc.contributor.departmentEnvironmental Science and Engineeringen
dc.date.accessioned2016-05-23T18:29:10Zen
dc.date.available2016-05-23T18:29:10Zen
dc.date.issued1986en
dc.description.abstractAn automated tungstic acid technique (TAT) has been successfully used to measure gaseous HNO₃ in the presence of water vapor. The TAT is based on the diffusion of gaseous HNO₃ to the interior walls of a tube coated with tungsten VI oxide (WO₃), where it is selectively chemisorbed. The collected HNO₃ sample is thermally desorbed from the WO₃ surface, as NO, and measured by a chemiluminescent oxides of nitrogen analyzer. The integrated analyzer response is directly proportional to the nitric acid collected. Based on nitric acid hydration characteristics, a decrease in the diffusion coefficient and thus collection efficiency for denuder type measurement techniques may result with increased atmospheric water vapor (i.e., relative humidity). This study emphasizes the effect of water vapor (i.e., relative humidity) as a potential interferent for HNO₃ collection with the TAT system. The effect of water vapor (< 78% RH) on the collection efficiency for HNO₃ with the tungstic acid technique is negligible at 25°C, but is significant only at elevated sampling temperatures. This threshold effect is further substantiated and eliminated when a modified sampling collection system was designed with coolant capabilities. The new design has been tested to sub-part-per-billion (NO<sub>x</sub> analyzer detection limit) levels with minimal loss of gaseous HNO₃ signal, thereby increasing sensitivity to atmospheric HNO₃ concentrations and maintaining the gas/aerosol sample integrity.en
dc.description.degreePh. D.en
dc.format.extentx, 123 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/10919/71262en
dc.language.isoen_USen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 15233886en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1986.M375en
dc.subject.lcshNitric aciden
dc.subject.lcshAir quality -- Measurementen
dc.subject.lcshAir sampling apparatusen
dc.subject.lcshAcid rainen
dc.titleInvestigation of water vapor effects on the detection of nitric acid vapor with the tungstic acid techniqueen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineEnvironmental Science and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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