Tropospheric Chemistry: Instruments

HNO3 instrument in aircraft

HNO3 instrument (left) mounted in NOAA WP-3D aircraft.

Nitric Acid (HNO3) CIMS

Principle of the Measurement

Chemical Ionization Mass Spectrometry (CIMS) using I- or SiF5- ion chemistry

Species Measured


Time Response

1 Second

Detection Limit

Precision on 1 s HNO3 data: 20 pptv (1 sigma)


±(20% + 40 pptv)


custom built

Field Projects

  • SOS 1999
  • TexAQS 2000
  • ITCT 2002
  • ICARTT 2004
  • Mesa 2005
  • TexAQS 2006
  • ARCPAC 2008 (to measure halogens)
  • CalNex 2010
  • SENEX 2013
  • SONGNEX 2015


  • NOAA WP-3D aircraft


Andy Neuman

Key Publications

Neuman, J. A., M. Trainer, K. C. Aikin, W. M. Angevine, J. Brioude, S. S. Brown, J. A. de Gouw, W. P. Dube, M. Graus, J. H. Flynn, J. S. Holloway, B. L. Lefer, P. Nedelec, J. B. Nowak, D. D. Parrish, I. B. Pollack, J. M. Roberts, T. B. Ryerson, H. Smit, V. Thouret, and N. L. Wagner, Observations of ozone transport from the free troposphere to the Los Angeles basin, J. Geophys. Res., doi:10.1029/2011JD016919, 2012.

Neuman, J. A., J. B. Nowak, L. G. Huey, J . B. Burkholder, J. E. Dibb, J. S. Holloway, J. Liao, J. Peischl, J. M. Roberts, T. B. Ryerson, E. Scheuer, H. Stark, R. E. Stickel, D. J. Tanner, and A. Weinheimer, Bromine measurements in ozone depleted air over the Arctic Ocean, Atmos. Chem. Phys., doi:10.5194/acp-10-6503-2010, 2010.

Neuman, J. A., T. B. Ryerson, L. G. Huey, R. Jakoubek, J. B. Nowak, C. Simons, and F. C. Fehsenfeld, Calibration and evaluation of nitric acid and ammonia permeation tubes by UV optical absorption, Environ. Sci. Technol., doi:10.1021/ES06422L, 2003.

Neuman, J. A., L. G. Huey, R. W. Dissly, F. C. Fehsenfeld, F. Flocke, J. C. Holecek, J. S. Holloway, G. Hübler, R. Jakoubek, D. K. Nicks Jr., D. D. Parrish, T.B. Ryerson, D. T. Sueper, and A. J. Weinheimer, Fast-response airborne in situ measurements of HNO3 during the Texas 2000 Air Quality Study, J. Geophys. Res., doi:10.1029/2001JD001437, 2002.