Advertisement

Real-time and Non-intrusive Detection of Ambient Ammonia using the Photothermal Deflection Technique

  • H. S. M. de Vries
  • F. J. M. Harren
  • G. P. Wyers
  • R. P. Otjes
  • J. Slanina
  • J. Reuss
Chapter
Part of the Transport and Chemical Transformation of Pollutants in the Troposphere book series (3373, volume 4)

Summary

The recent development of a non-intrusive photothermal deflection (PD) instrument allows the quantitative detection of local ammonia concentrations in air to be measured continuously, sensitively and fast. Ammonia is vibrationally excited by an infrared CO2 laser in an intracavity configuration. A HeNe beam passes over the CO2 laser beam in a multipass arrangement and is deflected by a thermal, CO2 laser induced, refractive index gradient. This deflection, due to the mirage effect, is a measure for the local ammonia concentration. In ambient air the detection limit is 0.5 ppb and the spatial resolution is 2.5 cm times π (0.282 mm2). The time resolution is 0.1 s for single line operation and 15 s for multi-line operation. The system is fully automated and suited for measuring periods of at least one week. Results are compared with those of a continuous-flow denuder system.

Keywords

Ammonia Concentration Mirage Effect Detection Zone Trace Substance Refractive Index Gradient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    G.J. Heij, J. Schneider, Report 200-09, Dutch priority programme on acidification, Bithoven 1991.Google Scholar
  2. 2.
    J.W. Erisman, A.W.M. Vermetten, W.A.H. Asman, A. Waijers-Ijpelaan, J. Slanina, Atmos. Environ. 22 (1988) (1153).CrossRefGoogle Scholar
  3. 3.
    A. Olafsson, M. Hammerich, J. Bülow, J. Henningsen, Appl. Phys. B49 (1989) 91.Google Scholar
  4. 4.
    W. Meienburg, H. Neckel, J. Wolfrum, Appl Phys. B51 (1990) 94.Google Scholar
  5. 5.
    R.A. Rooth, A.J.L. Verhage, L.W. Wouters, Appl. Opt. 29 (1990) (3643).CrossRefGoogle Scholar
  6. 6.
    U.A.M. Sauren, D. Bicanic, K. van Asselt, Infrared Phys. 31 (1991) (475).CrossRefGoogle Scholar
  7. 7.
    S.A. Trushin, Ber. Bunsenges. Phys. Chem. 96 (1992) (319).CrossRefGoogle Scholar
  8. 8.
    G.P. Wyers, R.P. Otjes, J. Slanina, Atmos. Environ. 27 (1993) (2085).CrossRefGoogle Scholar
  9. 9.
    D.W. Stocker, D.H. Stedman, K.F. Zeller, W.J. Massman, D.G. Fox, J. Geophys. Res. 98 (1993) (12619).CrossRefGoogle Scholar
  10. 10.
    F.J.M. Harren, F.G.C. Bijnen, J. Reuss, L.A.C.J. Voesenek, C.W.P.M. Blom, Appl. Phys. B50 (1990) 137.Google Scholar
  11. 11.
    W.B. Jackson, N.M. Amer, A.C. Boccara, D. Fournier, Appl. Opt. 20 (1981) (1333).CrossRefGoogle Scholar
  12. 12.
    H.S.M. de Vries, N. Dam, M.R. van Lieshout, C. Sikkens, F.J.M. Harren, J. Reuss, Rev. Sci. Instrum. in press.Google Scholar
  13. 13.
    H.S.M. de Vries, Local trace gas measurements by laser photothermal detection; physics meets physiology, Thesis, University of Nijmegen, 1994.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • H. S. M. de Vries
    • 1
  • F. J. M. Harren
    • 1
  • G. P. Wyers
    • 2
  • R. P. Otjes
    • 2
  • J. Slanina
    • 2
  • J. Reuss
    • 1
  1. 1.Department of Molecular and Laser PhysicsUniversity of Nijmegen, ToernooiveldNijmegenThe Netherlands
  2. 2.Netherlands Energy Research Foundation ECNPettenThe Netherlands

Personalised recommendations