Composition and Chemistry
Development and characterization of an airborne-based instrument used to measure nitric acid during the NASA Transport and Chemical Evolution over the Pacific field experiment
Article first published online: 23 SEP 2003
Copyright 2003 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 108, Issue D20, 27 October 2003
How to Cite
2003), Development and characterization of an airborne-based instrument used to measure nitric acid during the NASA Transport and Chemical Evolution over the Pacific field experiment, J. Geophys. Res., 108, 8793, doi:10.1029/2002JD003234, D20., , , , and (
- Issue published online: 23 SEP 2003
- Article first published online: 23 SEP 2003
- Manuscript Accepted: 18 APR 2003
- Manuscript Revised: 21 FEB 2003
- Manuscript Received: 27 NOV 2002
- HNO3 CIMS TRACE-P inlet instrument
 A new inlet and instrument have been developed for the rapid measurement of gas phase nitric acid (HNO3) from an airborne platform. The inlet was kept near ambient temperatures with a very short sampling time (100 ms) to minimize desorption of particle nitrates. In addition, inlet surface adsorption problems were minimized by the use of extruded perfluoroalkoxy as a sampling material. Nitric acid was detected by selected ion chemical ionization mass spectrometry using deprontonated methanesulfonic acid as a reagent ion. Laboratory tests showed no interferences from NO, NO2, NO3, and N2O5 under wet (relative humidity (RH) = 100%) or dry (RH = 0%) conditions at levels exceeding those found in the troposphere. The inlet and instrument were flown on the NASA P-3B aircraft as part of the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) field campaign off the coast of Asia during February–April 2001. Nitric acid was measured every 5 s for a 3 s integration period with a limit of detection of ∼10 parts per trillion by volume (pptv). The instrument was calibrated by the addition of isotopically labeled H15NO3 near the front of the ion source on a continual basis. Absolute uncertainties including systematic errors are the limit of detection (10 pptv) plus ±20% for HNO3 > 200 pptv, ±25% for HNO3 100–200 pptv, and ±30% for HNO3 < 100 pptv (±2 σ). Rapid changes in ambient HNO3 were resolved, suggesting minimal influences from instrument surfaces. Finally, the measurements compared favorably with the University of New Hampshire’s mist chamber/ion chromatography instrument flown on board the NASA DC-8 aircraft during two intercomparison flights. The in-flight performance of the instrument is demonstrated under the wide range of conditions observed in TRACE-P.