An intercomparison of airborne nitric acid measurements

Journal Article · Wed Jun 20 00:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JD095iD07p10089· OSTI ID:5330069

Gregory, G L; Hoell, Jr, J M; LeBel, P J; Vay, S A ^[1]; Huebert, B J ^[2]; Van Bramer, S E ^[3]; Marinaro, R M ^[4]; Schiff, H I; Hastie, D R ^[5]; Mackay, G I; Karecki, D R ^[6]

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1. NASA Langley Research Center, Hampton, VA (USA)
2. Univ. of Rhode Island, Narragansett (USA)
3. Colorado College, Colorado Springs (USA)
4. Vigyan Research Associates, Inc., Hampton, VA (USA)
5. York Univ., North York, Ontario (Canada)
6. Unisearch Associates, Concord, Ontario (Canada)

Instruments intercompared included a denuder tube collection system (DENUDER) with chemiluminescent detection, a nylon filter collection system (FILTER) with ion chromatography detection, and a tunable diode laser (TDLAS) multipath absorption system. While results were somewhat soft and data sparse, these tests suggested that the TDLAS measurements might be high compared to the other techniques. Airborne intercomparisons were conducted predominantly in the free troposphere and included encounters with marine and continental air masses. While the intercomparisons included mixing ratios to 1,000 parts per trillion by volume (pptv), the majority of the results were for mixing ratios of <300 pptv. While the lack of simultaneous measurements from the three instruments limits the conclusions that can be drawn, it is clear that there can be substantial disagreement among the three techniques, even at mixing ratios above their respective detection limits. Equally clear is that at mixing ratios below 150 pptv there is very little correlation between their results. Based on these observations, an overall conclusion from the intercomparison is that none of the HNO{sub 3} techniques can be identified to unambiguously (e.g., 20% accuracy) provide measurements of HNO{sub 3} at levels often encountered in the free troposphere (e.g., 100 pptv). However, at the more elevated levels of HNO{sub 3} (e.g., >150 pptv), both the FILTER and DENUDER techniques reported the same levels of nitric acid, while as suggested by the results from the standards intercomparison, the TDLAS reported higher nitric acid values than the other two techniques.

• OSTI ID: 5330069
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:D7; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

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