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@TECHREPORT{Ehhalt:136084,
      author       = {Ehhalt, D. H. and Schmidt, U. and Schubert, B.},
      title        = {{U}ntersuchungen zum {N}achweis und zur {C}hemie von
                      {F}ormaldehyd und {A}cetaldehyd in der unteren
                      {T}roposphäre},
      volume       = {2257},
      number       = {Juel-2257},
      address      = {Jülich},
      publisher    = {Kernforschungsanlage Jülich GmbH Zentralbibliothek,
                      Verlag},
      reportid     = {PreJuSER-136084, Juel-2257},
      series       = {Berichte der Kernforschungsanlage Jülich},
      pages        = {200 S.},
      year         = {1988},
      note         = {Record converted from JUWEL: 18.07.2013},
      abstract     = {A method for determining formaldehyde mixing ratios in
                      tropospheric air has been modified for the additional
                      measurement of acetaldehyde. The technique is based on
                      stripping of the aldehydes from the air into an aqueous
                      2,4-dinitrophenylhydrazine solution. The reaction products,
                      the 2,4-dinitrophenzlhydrazones of the respective aldehydes,
                      are separated using high performance liquid chromatography
                      and quantified by UV absorption. In clean air, measurements
                      can be performed with a time resolution of two hours. An
                      interference of the formaldehyde determination performed
                      with the modified technique is discussed . It was noticed
                      only in continental air in summer and led to increased
                      formaldehyde mixing ratios. For the detection of
                      acetaldehyde, no interference has been observed.
                      Formaldehyde and acetaldehyde mixing ratios were determined
                      in continental air and over the Atlantic ocean during two
                      cruises of the German research vessel "Polarstern" from 30
                      $^\circ$S and 50 $^\circ$N. In slightly polluted continental
                      air, the mean mixing ratios of formaldehyde and acetaldehyde
                      were 1.53 $\pm$ 0.76 ppb and 0.52 $\pm$ 0.61 ppb, much
                      higher than the mean values of 0.4 $\pm$ 0.19 ppb for
                      formaldehyde and 0.19 $\pm$ 0.13 ppb for acetaldehyde
                      observed in marine air. Simultaneous measurements of ethene
                      and propene concentrations showed a similar latitudinal
                      distribution as formaldehyde mixing ratios, confirming the
                      importance of alkenes for the aldehyde production predicted
                      by models. The influence of nonmethane hydrocarbons is
                      further indicated by the fact that the formaldehyde mixing
                      ratios are correlated with the sum of the C$_{2}$ - C$_{4}$
                      hydrocarbon concentrations in both, marine and continental
                      air. On sunny days, diurnal variations with maxima during
                      the early afternoon and nocturnal minima were observed for
                      both aldehydes in continental air as well as in maritime
                      air. The diurnal profiles of the measurements in maritime
                      air are compared to the results of a 1 D boundary layer
                      model. In continental air during the day the measured ozone
                      and formaldehyde concentrations showed a positive
                      correlation, while the diurnal variations were
                      anticorrelated in marine air. This anticorrelation indicates
                      photochemical estruction of ozone.},
      cin          = {ICG-2},
      ddc          = {540},
      cid          = {I:(DE-Juel1)VDB791},
      typ          = {PUB:(DE-HGF)29},
      url          = {https://juser.fz-juelich.de/record/136084},
}