Fluxes of monoterpenes from a spruce forest: establishing sampling and analytical procedures
2 Atmospheric Chemistry Division, National Center for Atmospheric Research
O 2.11 in Research in its Prime: First Results of Ongoing Research
10.10.2013, 12:15-12:30, H6, GEO
Biogenic volatile organic compounds (BVOC) are thought to be responsible for the growth of newly formed secondary organic aerosol (Kulmala and Kerminen, 2008). Oxidation products of monoterpenes (MT) were shown to have an important impact (Birmili et al., 2003). New particle formation (NPF) events have frequently been observed at the Waldstein site by our working group (e.g. Held et al., 2004). For better understanding of the observed particle growth measurements of organic precursors are crucial. Therefore, a relaxed eddy accumulation sampler developed by the National Center for Atmospheric Research (NCAR) was installed at the Waldstein main tower for measuring fluxes and ambient concentrations of BVOCs. The conditional sampler is based on sorbent-cartridges specific for collecting MT. Analysis was carried out at NCAR using gaschromatographic-mass spectrometry coupled to a flame ionization detector (GC-MS-FID).
Ambient concentrations at ppt to ppb levels were detected. α-pinene showed the highest contribution to the meassured MT concentrations. In addition, β-pinene, camphene, limonene, eucalyptol and δ3-carene were traced. Fluxes of BVOCs were determined on selected days only. Preliminary results indicate higher concentrations in the upward direction than in the downward direction which means a positive emission flux of MT out of the forest. These MT can be oxidized in the atmosphere and consequently contribute to the observed particle growth.
References
Birmili, W. et al. (Apr. 2003). “The Hohenpeissenberg aerosol formation experiment (HAFEX): a long-term study including size-resolved aerosol, H2SO4, OH, and monoterpenes measurements”.
In: Atmospheric Chemistry and Physics 3, pp. 361–376.
Held, A. et al. (Dec. 2004). “Observations of particle formation and growth in a mountainous forest region in central Europe”. In: Journal of Geophysical Research-atmospheres 109.D23, p. D23204.
doi: 10.1029/2004JD005346.
Kulmala, M. and V. M. Kerminen (Nov. 2008). “On the formation and growth of atmospheric nanoparticles”. In: Atmospheric Research 90.2-4, pp. 132–150. doi: 10.1016/j.atmosres.2008.01.005.
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