Deployment of a ground-based CIMS apparatus for the detection of organic gases in the boreal forest during the QUEST campaign K. Sellegri, B. Umann, M. Hanke, and F. Arnold Atmospheric Physic Division, Max Planck Institute for Nuclear Physics, Heidelberg, Germany
Abstract. Measurements of atmospheric volatile organic compounds were performed in the
Finnish Boreal forest atmosphere during spring 2003, as part of the project
QUEST (Quantification of Aerosol Nucleation in the European Boundary Layer),
using a ground-based Chemical Ionization Mass Spectrometer (CIMS)
instrument. Based on the study of their hydrate distribution, methanol,
acetonitrile, acetaldehyde, dimethyl amine (DMA), ethanol/formic acid,
acetone, trimethyl amine (TMA), propanol/acetic acid, isoprene, methyl vinyl
ketone (MVK) and metacrolein (MaCR), monoterpenes and monoterpene oxidation
product (MTOP) are proposed as candidates for masses 32, 41, 44, 45, 46, 58,
59, 60, 68, 70, 136, and 168amu, respectively. It would be, to our
knowledge, the first time DMA, TMA and MTOP are measured with this method.
Most compounds show a clear diurnal variation with a maximum in the early
night, corresponding to the onset of the noctural inversion and in agreement
with independant measurements of CO. Biogenic compounds are highly
correlated with each other and the ratio monoterpene/oxidation product shows
a typical daily pattern of nightime maxima. However, because isoprene mixing
ratios are also maximum during the early night, it is likely that it suffers
of the interference from another unidentified biogenic compound. Hence mass
68amu is identified as isoprene+compound X.
Citation: Sellegri, K., Umann, B., Hanke, M., and Arnold, F.: Deployment of a ground-based CIMS apparatus for the detection of organic gases in the boreal forest during the QUEST campaign, Atmos. Chem. Phys., 5, 357-372, doi:10.5194/acp-5-357-2005, 2005.