Eddy covariance VOC emission and deposition fluxes above grassland using PTR-TOF
Open Access
- 20 January 2011
- journal article
- research article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 11 (2), 611-625
- https://doi.org/10.5194/acp-11-611-2011
Abstract
Eddy covariance (EC) is the preferable technique for flux measurements since it is the only direct flux determination method. It requires a continuum of high time resolution measurements (e.g. 5–20 Hz). For volatile organic compounds (VOC) soft ionization via proton transfer reaction has proven to be a quantitative method for real time mass spectrometry; here we use a proton transfer reaction time of flight mass spectrometer (PTR-TOF) for 10 Hz EC measurements of full mass spectra up to m/z 315. The mass resolution of the PTR-TOF enabled the identification of chemical formulas and separation of oxygenated and hydrocarbon species exhibiting the same nominal mass. We determined 481 ion mass peaks from ambient air concentration above a managed, temperate mountain grassland in Neustift, Stubai Valley, Austria. During harvesting we found significant fluxes of 18 compounds distributed over 43 ions, including protonated parent compounds, as well as their isotopes and fragments and VOC-H+ – water clusters. The dominant BVOC fluxes were methanol, acetaldehyde, ethanol, hexenal and other C6 leaf wound compounds, acetone, acetic acid, monoterpenes and sequiterpenes. The smallest reliable fluxes we determined were less than 0.1 nmol m−2 s−1, as in the case of sesquiterpene emissions from freshly cut grass. Terpenoids, including mono- and sesquiterpenes, were also deposited to the grassland before and after the harvesting. During cutting, total VOC emission fluxes up to 200 nmolC m−2 s−1 were measured. Methanol emissions accounted for half of the emissions of oxygenated VOCs and a third of the carbon of all measured VOC emissions during harvesting.Keywords
Funding Information
- European Commission (218065)
This publication has 53 references indexed in Scilit:
- Detection of Plant Volatiles after Leaf Wounding and Darkening by Proton Transfer Reaction “Time-of-Flight” Mass Spectrometry (PTR-TOF)PLOS ONE, 2011
- Evidence for the role of organics in aerosol particle formation under atmospheric conditionsProceedings of the National Academy of Sciences of the United States of America, 2010
- Leaf area controls on energy partitioning of a temperate mountain grasslandBiogeosciences (online), 2008
- Reconciling Carbon-cycle Concepts, Terminology, and MethodsEcosystems, 2006
- Disjunct eddy covariance measurements of oxygenated volatile organic compounds fluxes from an alfalfa field before and after cuttingJournal of Geophysical Research: Solid Earth, 2002
- Eddy covariance measurements of oxygenated volatile organic compound fluxes from crop harvesting using a redesigned proton‐transfer‐reaction mass spectrometerJournal of Geophysical Research: Solid Earth, 2001
- Volatile organic compounds emitted after leaf wounding: On‐line analysis by proton‐transfer‐reaction mass spectrometryJournal of Geophysical Research: Solid Earth, 1999
- Measurements of N2O fluxes from fertilized grassland using a fast response tunable diode laser spectrometerJournal of Geophysical Research: Solid Earth, 1994
- A qualitative assessment of the emission of non-methane hydrocarbon compounds from the biosphere to the atmosphere in the U.K.: Present knowledge and uncertaintiesAtmospheric Environment. Part A. General Topics, 1992
- Uncorrelated Noise in Turbulence MeasurementsJournal of Atmospheric and Oceanic Technology, 1985