% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Glowania:893098,
      author       = {Glowania, Marvin and Rohrer, Franz and Dorn, Hans-Peter and
                      Hofzumahaus, Andreas and Holland, Frank and Kiendler-Scharr,
                      Astrid and Wahner, Andreas and Fuchs, Hendrik},
      title        = {{C}omparison of formaldehyde measurements by {H}antzsch,
                      {CRDS} and {DOAS} in the {SAPHIR} chamber},
      journal      = {Atmospheric measurement techniques},
      volume       = {14},
      number       = {6},
      issn         = {1867-8548},
      address      = {Katlenburg-Lindau},
      publisher    = {Copernicus},
      reportid     = {FZJ-2021-02557},
      pages        = {4239 - 4253},
      year         = {2021},
      abstract     = {Three instruments that use different techniques to measure
                      gaseous formaldehyde (HCHO) concentrations were compared in
                      experiments in the atmospheric simulation chamber SAPHIR at
                      Forschungszentrum Jülich. One instrument (AL4021,
                      Aero-Laser GmbH) detects HCHO using the wet-chemical
                      Hantzsch reaction (for efficient gas-phase stripping),
                      chemical conversion and fluorescence measurement. An
                      internal HCHO permeation source allows for daily
                      calibrations. This instrument was characterized by sulfuric
                      acid titration (overall accuracy $8.6 \%)$ and yields
                      measurements with a time resolution of 90 s and a limit of
                      detection (3σ) of 0.3 ppbv. In addition, a new commercial
                      instrument that makes use of cavity ring-down spectroscopy
                      (CRDS) determined the concentrations of HCHO, water vapour,
                      and methane (G2307, Picarro, Inc.). Its limit of detection
                      (3σ) is specified as 0.3 ppbv for an integration time of
                      300 s, and its accuracy is limited by the drift of the
                      zero signal (manufacturer specification 1.5 ppbv). A
                      custom-built high-resolution laser differential optical
                      absorption spectroscopy (DOAS) instrument provided HCHO
                      measurements with a limit of detection (3σ) of 0.9 ppbv
                      and an accuracy of $7 \%​​​​​​​$ using an
                      optical multiple reflection cell. The measurements were
                      conducted from June to December 2019 in experiments in which
                      either ambient air flowed through the chamber or the
                      photochemical degradation of organic compounds in synthetic
                      air was investigated. Measured HCHO concentrations were up
                      to 8 ppbv. Various mixtures of organic compounds, water
                      vapour, nitrogen oxides and ozone were present in these
                      experiments. Results demonstrate the need to correct the
                      baseline in measurements performed by the Hantzsch
                      instrument to compensate for drifting background signals.
                      Corrections were equivalent to HCHO mixing ratios in the
                      range of 0.5–1.5 ppbv. The baseline of the CRDS
                      instrument showed a linear dependence on the water vapour
                      mixing ratio with a slope of
                      $(−11.20±1.60) ppbv \%−1$ below and
                      $(−0.72±0.08) ppbv \%−1$ above a water vapour
                      mixing ratio of $0.2 \%.$ In addition, the intercepts of
                      these linear relationships drifted within the specification
                      of the instrument (1.5 ppbv) over time but appeared to be
                      equal for all water mixing ratios. Regular zero measurements
                      are needed to account for the changes in the instrument
                      zero. After correcting for the baselines of measurements by
                      the Hantzsch and the CRDS instruments, linear regression
                      analysis of measurements from all three instruments in
                      experiments with ambient air indicated good agreement, with
                      slopes of between 0.98 and 1.08 and negligible intercepts
                      (linear correlation coefficients R2>0.96). The new small
                      CRDS instrument measures HCHO with good precision and is
                      accurate if the instrument zero is taken into account.
                      Therefore, it can provide measurements with similar accuracy
                      to the DOAS instrument but with slightly reduced precision
                      compared to the Hantzsch instrument.},
      cin          = {IEK-8},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-8-20101013},
      pnm          = {211 - Die Atmosphäre im globalen Wandel (POF4-211)},
      pid          = {G:(DE-HGF)POF4-211},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000661421100001},
      doi          = {10.5194/amt-14-4239-2021},
      url          = {https://juser.fz-juelich.de/record/893098},
}