Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 9 6 2009 10.5194/acp-9-2061-2009 http://www.atmos-chem-phys.net/9/2061/2009/ http://www.atmos-chem-phys.net/9/2061/2009/acp-9-2061-2009.html http://www.atmos-chem-phys.net/9/2061/2009/acp-9-2061-2009.pdf 2061 2074 2009-03-23 Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere N. C. Bouvier-Brown A. H. Goldstein D. R. Worton D. M. Matross J. B. Gilman W. C. Kuster D. Welsh-Bon C. Warneke J. A. de Gouw T. M. Cahill R. Holzinger Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, USA NOAA Earth System Research Laboratory & Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, CO, USA Division of Mathematical and Natural Sciences, Arizona State University, West Campus, Phoenix, AZ, USA Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, The Netherlands We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg^−1 h^−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. 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