Articles | Volume 13, issue 5
Research article
05 May 2020
Research article |  | 05 May 2020

The influence of the baseline drift on the resulting extinction values of a cavity attenuated phase shift-based extinction monitor (CAPS PMex)

Sascha Pfeifer, Thomas Müller, Andrew Freedman, and Alfred Wiedensohler

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Cited articles

Brown, S. S.: Absorption Spectroscopy in High-Finesse Cavities for Atmospheric Studies, Chem. Rev., 103, 5219–5238, 2003. a
Kebabian, P. L., Scott, S. C., and Freedman, A.: Detection of Nitrogen Dioxide by Cavity Attenuated Phase Shift Spectroscopy, Analyt. Chem., 77, 724–728, 2005.  a
Kebabian, P. L., Wood, E. C., Herndon, S. C., and Freedman, A.: A Practical Alternative to Chemiluminescence-Based Detection of Nitrogen Dioxide: Cavity Attenuated Phase Shift Spectroscopy, Environ. Sci. Technol., 42, 6040–6045, 2008. a
Massoli, P., Kebabian, P. L., Onasch, T. B., Hills, F. B., and Freedman, A.: Aerosol light extinction measurements by cavity attenuated phase shift (CAPS) spectroscopy: Laboratory validation and field deployment of a compact aerosol particle extinction monitor, Aerosol Sci. Technol., 44, 428–435, 2010. a, b, c
Müller, T., Laborde, M., Kassell, G., and Wiedensohler, A.: Design and performance of a three-wavelength LED-based total scatter and backscatter integrating nephelometer, Atmos. Meas. Tech., 4, 1291–1303,, 2011. a
Short summary
The effect of the baseline drift on the resulting extinction values of three CAPS PMex monitors with different wavelengths was analysed for an urban background station. A significant baseline drift was observed, which leads to characteristic measurement artefacts for particle extinction. Two alternative methods for recalculating the baseline are shown. With these methods the extinction artefacts are diminished and the effective scattering of the resulting extinction values is reduced.