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Scientific Articles - PTR-MS Bibliography

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[Guenther1995] Guenther, A., N. C Hewitt, D. Erickson, R. Fall, C. Geron, T. Graedel, P. Harley, L. Klinger, M. Lerdau, WA. McKay, et al., "A global model of natural volatile organic compound emissions", Journal of Geophysical research, vol. 100, no. D5: American Geophysical Union, pp. 8873–8892, 1995.
Link: http://www.agu.org/pubs/crossref/1995/94JD02950.shtml
Abstract
Numerical assessments of global air quality and potential changes in atmospheric chemical constituents require estimates of the surface fluxes of a variety of trace gas species. We have developed a global model to estimate emissions of volatile organic compounds from natural sources (NVOC). Methane is not considered here and has been reviewed in detail elsewhere. The model has a highly resolved spatial grid (0.5°×0.5° latitude/longitude) and generates hourly average emission estimates. Chemical species are grouped into four categories: isoprene, monoterpenes, other reactive VOC (ORVOC), and other VOC (OVOC). NVOC emissions from oceans are estimated as a function of geophysical variables from a general circulation model and ocean color satellite data. Emissions from plant foliage are estimated from ecosystem specific biomass and emission factors and algorithms describing light and temperature dependence of NVOC emissions. Foliar density estimates are based on climatic variables and satellite data. Temporal variations in the model are driven by monthly estimates of biomass and temperature and hourly light estimates. The annual global VOC flux is estimated to be 1150 Tg C, composed of 44% isoprene, 11% monoterpenes, 22.5% other reactive VOC, and 22.5% other VOC. Large uncertainties exist for each of these estimates and particularly for compounds other than isoprene and monoterpenes. Tropical woodlands (rain forest, seasonal, drought-deciduous, and savanna) contribute about half of all global natural VOC emissions. Croplands, shrublands and other woodlands contribute 10–20% apiece. Isoprene emissions calculated for temperate regions are as much as a factor of 5 higher than previous estimates.
[1491] Hewitt, C.. N., K.. Ashworth, A.. Boynard, A.. Guenther, B.. Langford, A.. R. MacKenzie, P.. K. Misztal, E.. Nemitz, S.. M. Owen, M.. Possell, et al., "Ground-level ozone influenced by circadian control of isoprene emissions", Nature Geoscience, vol. 4, pp. 671–674, 2011.
Abstract
<p>The volatile organic compound isoprene is produced by many plant species, and provides protection against biotic and abiotic stresses1. Globally, isoprene emissions from plants are estimated to far exceed anthropogenic emissions of volatile organic compounds2. Once in the atmosphere, isoprene reacts rapidly with hydroxyl radicals3 to form peroxy radicals, which can react with nitrogen oxides to form ground-level ozone4. Here, we use canopy-scale measurements of isoprene fluxes from two tropical ecosystems in Malaysia&mdash;a rainforest and an oil palm plantation&mdash;and three models of atmospheric chemistry to explore the effects of isoprene fluxes on ground-level ozone. We show that isoprene emissions in these ecosystems are under circadian control on the canopy scale, particularly in the oil palm plantation. As a result, these ecosystems emit less isoprene than present emissions models predict. Using local-, regional- and global-scale models of atmospheric chemistry and transport, we show that accounting for circadian control of isoprene emissions brings model predictions of ground-level ozone into better agreement with measurements, especially in isoprene-sensitive regions of the world.</p>
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[1627] Sahu, L.K.., and P. Saxena, "High time and mass resolved PTR-TOF-MS measurements of VOCs at an urban site of India during winter: Role of anthropogenic, biomass burning, biogenic and photochemical sources", Atmospheric Research, vol. 164-165, pp. 84–94, Oct, 2015.
Link: http://dx.doi.org/10.1016/j.atmosres.2015.04.021
Abstract
<p>This study is based on the high mass and time-resolved measurements of seven VOCs using a PTR-TOF-MS instrument at an urban site of India during winter 2013. Daily levels of OVOCs and aromatics were in the ranges of 3.5&ndash;37 ppbv and 0.85&ndash;23 ppbv, respectively with OVOCs accounted for up to 80% of total measured VOCs. The impact of long-range transport from the polluted Indo-Gangetic Plain and clean Thar desert was observed during the episodes of high and low VOCs, respectively. VOCs exhibited strong diurnal variations with peaks during morning and evening hours and lowest in the afternoon. Relatively elevated aromatics during evening hours coincided with the lowest-OVOCs indicating influence of fresh vehicular emissions. Emission ratios of isoprene and OVOCs with respect to benzene followed the diurnal cycles of temperature and solar flux indicating role of biogenic and photochemical processes, respectively. Correlation study of VOCs with benzene suggests major contribution from anthropogenic and also from biogenic and secondary sources to some extent. The higher emission ratios of ∆methanol/∆acetonitrile correspond to the episodes of long-range transport from biomass burning sources located in the Indo-Gangetic Plain (IGP). In addition to the pattern of emission, the diurnal and day-to-day variations of VOCs were influenced by the local meteorological conditions and depth of planetary boundary layer (PBL).</p>
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[Pegoraro2005] Pegoraro, E., A. Rey, G. Barron-Gafford, R. Monson, Y. Malhi, and R. Murthy, "The interacting effects of elevated atmospheric CO2 concentration, drought and leaf-to-air vapour pressure deficit on ecosystem isoprene fluxes.", Oecologia, vol. 146, no. 1, pp. 120–129, Nov, 2005.
Link: http://dx.doi.org/10.1007/s00442-005-0166-5
Abstract
Isoprene is the most abundant biogenic hydrocarbon released from vegetation and it plays a major role in tropospheric chemistry. Because of its link to climate change, there is interest in understanding the relationship between CO2, water availability and isoprene emission. We explored the effect of atmospheric elevated CO2 concentration and its interaction with vapour pressure deficit (VPD) and water stress, on gross isoprene production (GIP) and net ecosystem exchange of CO2 (NEE) in two Populus deltoides plantations grown at ambient and elevated atmospheric CO2 concentration in the Biosphere 2 Laboratory facility. Although GIP and NEE showed a similar response to light and temperature, their responses to CO2 and VPD were opposite; NEE was stimulated by elevated CO2 and depressed by high VPD, while GIP was inhibited by elevated CO2 and stimulated by high VPD. The difference in response between isoprene production and photosynthesis was also evident during water stress. GIP was stimulated in the short term and declined only when the stress was severe, whereas NEE started to decrease from the beginning of the experiment. This contrasting response led the carbon lost as isoprene in both the ambient and the elevated CO2 treatments to increase as water stress progressed. Our results suggest that water limitation can override the inhibitory effect of elevated CO2 leading to increased global isoprene emissions in a climate change scenario with warmer and drier climate.
[Laffineur2011a] Laffineur, Q., M. Aubinet, N. Schoon, C. Amelynck, J-F. Müller, J. Dewulf, H. Van Langenhove, K. Steppe, M. Šimpraga, and B. Heinesch, "Isoprene and monoterpene emissions from a mixed temperate forest", Atmospheric Environment, vol. 45, no. 18: Elsevier, pp. 3157–3168, 2011.
Link: http://www.sciencedirect.com/science/article/pii/S1352231011001981
Abstract
<p>We measured the isoprene and monoterpene fluxes continuously above a mixed forest site at Vielsalm in the eastern part of Belgium, using the disjunct eddy covariance technique with proton transfer reaction-mass spectrometry. Simultaneously, we also measured the carbon dioxide fluxes in order to deduce the gross primary production. The measurements were conducted from July to September 2009. During the day, the seasonal evolution of the isoprene/monoterpene emissions was studied using a monthly temperature and light dependence function deduced from our results to standardize the fluxes. A seasonal decrease in the standard emission factors was observed, probably linked to acclimation or senescence. The standard emission factor for isoprene fluxes (30 &deg;C, 1000 μmol m&minus;2 s&minus;1) fell from 0.91 &plusmn; 0.01 to 0.56 &plusmn; 0.02 μg m&minus;2 s&minus;1 and for monoterpene fluxes from 0.74 &plusmn; 0.03 to 0.27 &plusmn; 0.03 μg m&minus;2 s&minus;1. During the night, a slight positive flux of monoterpenes was observed that seemed to be driven by air temperature. The standard emission factor (30&deg;C) for nighttime monoterpene fluxes was equal to 0.093 &plusmn; 0.019 μg m&minus;2 s&minus;1. Finally, we studied the seasonal evolution of the relationship between the gross primary production and the isoprene/monoterpenes fluxes. A linear relationship was observed, highlighting the strong link between carbon assimilation and isoprene/monoterpene emissions.</p>
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[Taipale2010] Taipale, R., T. M. Ruuskanen, and J. Rinne, "Lag time determination in DEC measurements with PTR-MS", Atmospheric Measurement Techniques Discussions, vol. 3, no. 1: Copernicus GmbH, pp. 405–429, 2010.
Link: http://www.atmos-meas-tech-discuss.net/3/405/2010/
Abstract
The disjunct eddy covariance (DEC) method has emerged as a popular technique for micrometeorological flux measurements of volatile organic compounds (VOCs). It has usually been combined with proton transfer reaction mass spectrometry (PTR-MS), an online technique for VOC concentration measurements. However, the determination of the lag time between wind and concentration measurements has remained an important challenge. To address this conundrum, we studied the effect of different lag time methods on DEC fluxes. The analysis was based on both actual DEC measurements with PTR-MS and simulated DEC data derived from high frequency H2O measurements with an infrared gas analyzer. Conventional eddy covariance fluxes of H2O served as a reference in the DEC simulation. The individual flux measurements with PTR-MS were rather sensitive to the lag time methods, but typically this effect averaged out when the median fluxes were considered. The DEC simulation revealed that the maximum covariance method was prone to overestimation of the absolute values of fluxes. The constant lag time methods, one resting on a value calculated from the sampling flow and the sampling line dimensions and the other on a typical daytime value, had a tendency to underestimate. The visual assessment method and our new averaging approach based on running averaged covariance functions did not yield statistically significant errors and thus fared better than the habitual choice, the maximum covariance method. Given this feature and the potential for automatic flux calculation, we recommend using the averaging approach in DEC measurements with PTR-MS.
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[1596] Tanimoto, H., S. Kameyama, T. Iwata, S. Inomata, and Y. Omori, "Measurement of air-sea exchange of dimethyl sulfide and acetone by PTR-MS coupled with gradient flux technique.", Environ Sci Technol, vol. 48, pp. 526–533, Jan, 2014.
Link: http://dx.doi.org/10.1021/es4032562
Abstract
<p>We developed a new method for in situ measurement of air-sea fluxes of multiple volatile organic compounds (VOCs) by combining proton transfer reaction-mass spectrometry (PTR-MS) and gradient flux (GF) technique. The PTR-MS/GF system was first deployed to determine the air-sea flux of VOCs in the open ocean of the western Pacific, in addition to carbon dioxide and water vapor. Each profiling at seven heights from the ocean surface up to 14 m took 7 min. In total, 34 vertical profiles of VOCs in the marine atmosphere just above the ocean surface were obtained. The vertical gradient observed was significant for dimethyl sulfide (DMS) and acetone with the best-fit curves on quasi-logarithmic relationship. The mean fluxes of DMS and acetone were 5.5 &plusmn; 1.5 and 2.7 &plusmn; 1.3 μmol/m(2)/day, respectively. These fluxes are in general in accordance with those reported by previous expeditions.</p>
[Kim2009a] Kim, S., T. Karl, D. Helmig, R. Daly, R. Rasmussen, and A. Guenther, "Measurement of atmospheric sesquiterpenes by proton transfer reaction-mass spectrometry (PTR-MS)", Atmospheric Measurement Techniques, vol. 2, no. 1: Copernicus GmbH, pp. 99–112, 2009.
Link: http://www.atmos-meas-tech.net/2/99/2009/
Abstract
The ability to measure sesquiterpenes (SQT; C15H24) by a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) was investigated. SQT calibration standards were prepared by a capillary diffusion method and the PTR-MS-estimated mixing ratios were derived from the counts of product ions and proton transfer reaction constants. These values were compared with mixing ratios determined by a calibrated Gas Chromatograph (GC) coupled to a Flame Ionization Detector (GC-FID). Product ion distributions from soft-ionization occurring in a selected ion drift tube via proton transfer were measured as a function of collision energies. Results after the consideration of the mass discrimination of the PTR-MS system suggest that quantitative SQT measurements within 20% accuracy can be achieved with PTR-MS if two major product ions (m/z 149+ and 205+), out of seven major product ions (m/z 81+, 95+, 109+, 123+, 135+, 149+ and 205+), are accounted for. Considerable fragmentation of bicyclic sesquiterpenes, i.e. β-caryophyllene and α-humulene, cause the accuracy to be reduced to 50% if only the parent ion (m/z 205+) is considered. These findings were applied to a field dataset collected above a deciduous forest at the PROPHET (Program for Research on Oxidants: Photochemistry, Emissions, and Transport) research station in 2005. Inferred average daytime ecosystem scale mixing ratios (fluxes) of isoprene, sum of monoterpenes (MT), and sum of SQT exhibited values of 15 μg m−3 (4.5 mg m−2 h−1), 1.2 μg m−3 (0.21 mg m−2 h−1), and 0.0016 μg m−3 (0.10 mg m−2 h−1), respectively. A range of MT and SQT reactivities with respect to the OH radical was calculated and compared to an earlier study inferring significantly underestimated OH reactivities due to unknown terpenes above this deciduous forest. The results indicate that incorporating these MT and SQT results can resolve  30% of missing OH reactivity reported for this site.
[1457] Beale, R., J. L. Dixon, S. R. Arnold, P. S. Liss, and P. D. Nightingale, "Methanol, acetaldehyde, and acetone in the surface waters of the Atlantic Ocean", Journal of Geophysical Research: Oceans, vol. 118, pp. 5412–5425, 2013.
Link: http://dx.doi.org/10.1002/jgrc.20322
Abstract
<p>Oceanic methanol, acetaldehyde, and acetone concentrations were measured during an Atlantic Meridional Transect (AMT) cruise from the UK to Chile (49&deg;N to 39&deg;S) in 2009. Methanol (48&ndash;361 nM) and acetone (2&ndash;24 nM) varied over the track with enrichment in the oligotrophic Northern Atlantic Gyre. Acetaldehyde showed less variability (3&ndash;9 nM) over the full extent of the transect. These oxygenated volatile organic compounds (OVOCs) were also measured subsurface, with methanol and acetaldehyde mostly showing homogeneity throughout the water column. Acetone displayed a reduction below the mixed layer. OVOC concentrations did not consistently correlate with primary production or chlorophyll-a levels in the surface Atlantic Ocean. However, we did find a novel and significant negative relationship between acetone concentration and bacterial leucine incorporation, suggesting that acetone might be removed by marine bacteria as a source of carbon. Microbial turnover of both acetone and acetaldehyde was confirmed. Modeled atmospheric data are used to estimate the likely air-side OVOC concentrations. The direction and magnitude of air-sea fluxes vary for all three OVOCs depending on location. We present evidence that the ocean may exhibit regions of acetaldehyde under-saturation. Extrapolation suggests that the Atlantic Ocean represents an overall source of these OVOCs to the atmosphere at 3, 3, and 1 Tg yr&minus;1 for methanol, acetaldehyde, and acetone, respectively.</p>
[Ghirardo2010a] Ghirardo, A., K. Koch, R. Taipale, I. Zimmer, J-P. Schnitzler, and J. Rinne, "Monoterpene emissions from boreal tree species: Determination of de novo and pool emissions", EGU General Assembly Conference Abstracts, vol. 12, pp. 2448, 2010.
Link: http://adsabs.harvard.edu/abs/2010EGUGA..12.2448G
Abstract
Boreal forests emit a large amount of monoterpenes into the atmosphere. Traditionally these emissions are assumed to originate as evaporation from large storage pools. Thus their diurnal cycle would depend mostly on temperature. However, there is indication that a significant part of the monoterpene emission would originate directly from de novo synthesis. By applying 13CO2 fumigation and analyzing the isotope fractions with proton transfer reaction mass spectrometry (PTR-MS) and classical GC-MS we studied the origin of monoterpene emissions from some major Eurasian boreal and alpine tree species. We determined the fractions originating from de novo biosynthesis and from large internal monoterpene storages for three coniferous tree species with specialized monoterpene storage structures and one dicotyledon species without such structures. The emission from dicotyledon species Betula pendula originated solely from the de novo synthesis. The origin of the emissions from coniferous species was mixed with varying fraction originating from de novo synthesis (Pinus sylvestris 58 %, Picea abies 33.5 %, Larix decidua 9.8 %) and the rest from large internal monoterpene storage pools. We have also measured the ecosystem scale monoterpene emission fluxes from a boreal Pinus sylvestris forest by disjunct eddy covariance technique. Application of the observed fraction of emission originating from de novo synthesis and large storage pools in a hybrid emission algorithm resulted in a better description of ecosystem scale monoterpene emissions, as compared to the measured fluxes.
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[Fares2013] Fares, S., R. Schnitzhofer, X. Jiang, A. Guenther, A. Hansel, and F. Loreto, "Observations of diurnal to weekly variations of monoterpene-dominated fluxes of volatile organic compounds from Mediterranean forests: implications for regional modeling.", Environ Sci Technol, Sep, 2013.
Link: http://dx.doi.org/10.1021/es4022156
Abstract
The Estate of Castelporziano (Rome, Italy) hosts many ecosystems representative of Mediterranean vegetation, especially holm oak and pine forests, and dune vegetation. In this work, Basal Emission Factors (BEFs) of biogenic volatile organic compounds (BVOCs) obtained by Eddy Covariance in a field campaign using a Proton Transfer Reaction - Time of Flight - Mass Spectrometer (PTR-TOF-MS) were compared to BEFs reported in previous studies that could not measure fluxes in real-time. Globally, broadleaf forests are dominated by isoprene emissions, but these Mediterranean ecosystems are dominated by strong monoterpene emitters, as shown by the new BEFs. The original and new BEFs were used to parameterize the Model of Emissions of Gases and Aerosols from Nature (MEGAN v2.1), and model outputs were compared with measured fluxes. Results showed good agreement between modelled and measured fluxes when a model was used to predict radiative transfer and energy balance across the canopy. We then evaluated whether changes in BVOC emissions can affect the chemistry of the atmosphere and climate at a regional level. MEGAN was run together with the land surface model (Community Land Model, CLM v4.0) of the Community Earth System Model (CESM v1.0). Results highlighted that tropospheric ozone concentration and air temperature predicted from the model are sensitive to the magnitude of BVOC emissions, thus demonstrating the importance of adopting the proper BEF values for model parameterization.
[1664] Zannoni, N.., V.. Gros, M.. Lanza, R.. Sarda, B.. Bonsang, C.. Kalogridis, S.. Preunkert, M.. Legrand, C.. Jambert, C.. Boissard, et al., "OH reactivity and concentrations of Biogenic Volatile Organic Compounds in a Mediterranean forest of downy oak trees", Atmos. Chem. Phys. Discuss., vol. 15, pp. 22047--22095, 2015.
Link: http://dx.doi.org/10.5194/acpd-15-22047-2015
Abstract
<p>Abstract. Understanding the processes between the biosphere and the atmosphere is challenged by the difficulty to determine with enough accuracy the composition of the atmosphere. Total OH reactivity, which is defined as the total loss of the hydroxyl radical in the atmosphere, has proved to be an excellent tool to identify indirectly the important reactive species in ambient air. High levels of unknown reactivity were found in several forests worldwide and were often higher than at urban sites. Such results demonstrated the importance of OH reactivity for characterizing two of the major unknowns currently present associated to forests: the set of primary emissions from the canopy to the atmosphere and biogenic compounds oxidation pathways. Previous studies also highlighted the need to quantify OH reactivity and missing OH reactivity at more forested sites. Our study presents results of a field experiment conducted during late spring 2014 at the forest site at the Observatoire de Haute Provence, OHP, France. The forest is mainly composed of downy oak trees, a deciduous tree species characteristic of the Mediterranean region. We deployed the Comparative Reactivity Method and a set of state-of-the-art techniques such as Proton Transfer Reaction-Mass Spectrometry and Gas Chromatography to measure the total OH reactivity, the concentration of volatile organic compounds and main atmospheric constituents at the site. We sampled the air masses at two heights: 2 m, i.e. inside the canopy, and 10 m, i.e. above the canopy, where the mean canopy height is 5 m. We found that the OH reactivity at the site mainly depended on the main primary biogenic species emitted by the forest, which was isoprene and to a lesser extent by its degradation products and long lived atmospheric compounds (up to 26 % during daytime). We determined that the daytime total measured reactivity equaled the calculated reactivity obtained from the concentrations of the compounds measured at the site. Hence, no significant missing reactivity is reported in this specific site, neither inside, nor above the canopy. However, during two nights we reported a missing fraction of OH reactivity up to 50 %, possibly due to unmeasured oxidation products. Our results confirm the weak intra canopy oxidation, already suggested in a previous study focused on isoprene fluxes. They also demonstrate how helpful can be the OH reactivity as a tool to clearly characterize the suite of species present in the atmosphere. We show that our result of reactivity is among the highest reported in forests worldwide and stress the importance to quantify OH reactivity at more and diverse Mediterranean forests.</p>
[Hayward2004] Hayward, S., A. Tani, S. M. Owen, and N. C Hewitt, "Online analysis of volatile organic compound emissions from Sitka spruce (Picea sitchensis).", Tree Physiol, vol. 24, no. 7: Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, LA1 4YQ, U.K., pp. 721–728, Jul, 2004.
Link: http://treephys.oxfordjournals.org/content/24/7/721.short
Abstract
Volatile organic compound (VOC) emissions from Sitka spruce (Picea sitchensis Bong.) growing in a range of controlled light and temperature regimes were monitored online with a proton transfer reaction-mass spectrometer (PTR-MS) operating at a temporal resolution of approximately 1 min. Isoprene emissions accounted for an average of more than 70% of measured VOCs and up to 3.5% of assimilated carbon. Emission rates (E) for isoprene correlated closely with photosynthetic photon flux (PPF) and temperature, showing saturation at a PPF of between 300 and 400 micromol m(-2) s(-1) and a maximum between 35 and 38 degrees C. Under standard conditions of 30 degrees C and 1000 micromol m(-2) s(-1) PPF, the mean isoprene E was 13 microg gdm(-1) h(-1), considerably higher than previously observed in this species. Mean E for acetaldehyde, methanol and monoterpenes at 30 degrees C were 0.37, 0.78 and 2.97 microg gdm(-1) h(-1), respectively. In response to a sudden light to dark transition, isoprene E decreased exponentially by > 98% over about 3 h; however, during the first 7 min, this otherwise steady decay was temporarily but immediately depressed to approximately 40% of the pre-darkness rate, before rallying during the following 7 min to rejoin the general downward trajectory of the exponential decay. The sudden sharp fall in isoprene E was mirrored by a burst in acetaldehyde E. The acetaldehyde E maximum coincided with the isoprene E minimum (7 min post-illumination), and ceased when isoprene emissions resumed their exponential decay. The causes of, and linkages between, these phenomena were investigated.
[Schade2004] Schade, G. W., and T. G. Custer, "OVOC emissions from agricultural soil in northern Germany during the 2003 European heat wave", Atmospheric Environment, vol. 38, no. 36: Elsevier, pp. 6105–6114, 2004.
Link: http://www.sciencedirect.com/science/article/pii/S1352231004007344
Abstract
Fluxes of methanol and acetone were measured from an agricultural field plot during one of the hottest weeks of the heat wave of the summer of 2003 in Europe. Significant positive fluxes from the bare, plowed soil for these oxygenated volatile organic compounds were found. Methanol fluxes ranged from 0 to 0.20 mg C m−2 h−1 while acetone fluxes ranged from −0.01 to 0.05. Mixing ratios for both methanol and acetone showed significant increases at night, consistent with a ground-based emission source for both the compounds. Methanol emissions were well correlated with sensible heat flux, peaking around noon. Assuming abiological production from soil organic matter in the topsoil, we calculate that 48 kJ mol−1 of energy is required to liberate the methanol from the topsoil. In contrast to methanol, acetone fluxes were not correlated with any measured meteorological parameter. This suggests that acetone has another source and may be produced in the soil subsurface, possibly through biological or moisture-driven processes. Using the flux data, we also simulated relaxed eddy accumulation (REA) experiments and reconfirm that sonic temperature can be used to calculate b-factors for REA analysis of a variety of trace gas fluxes.
[Beauchamp2005] Beauchamp, J., A. Wisthaler, A. Hansel, E. Kleist, M. Miebach, ÜLO. NIINEMETS, U. Schurr, and JÜRGEN. WILDT, "Ozone induced emissions of biogenic VOC from tobacco: relationships between ozone uptake and emission of LOX products", Plant, Cell & Environment, vol. 28, no. 10: Wiley Online Library, pp. 1334–1343, 2005.
Link: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.2005.01383.x/full
Abstract
Volatile organic compound (VOC) emissions from tobacco (Nicotiana tabacum L. var. Bel W3) plants exposed to ozone (O3) were investigated using proton-transfer-reaction mass-spectrometry (PTR-MS) and gas chromatography mass-spectrometry (GC-MS) to find a quantitative reference for plants’ responses to O3 stress. O3 exposures to illuminated plants induced post-exposure VOC emission bursts. The lag time for the onset of volatile C6 emissions produced within the octadecanoid pathway was found to be inversely proportional to O3 uptake, or more precisely, to the O3 flux density into the plants. In cases of short O3 pulses of identical duration the total amount of these emitted C6 VOC was related to the O3 flux density into the plants, and not to ozone concentrations or dose–response relationships such as AOT 40 values. Approximately one C6 product was emitted per five O3 molecules taken up by the plant. A threshold flux density of O3 inducing emissions of C6 products was found to be (1.6 ± 0.7) × 10−8 mol m−2 s−1.
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[Brilli2012] Brilli, F., L. Hörtnagl, I. Bamberger, R. Schnitzhofer, T. M. Ruuskanen, A. Hansel, F. Loreto, and G. Wohlfahrt, "Qualitative and quantitative characterization of volatile organic compound emissions from cut grass.", Environ Sci Technol, vol. 46, no. 7: Ionicon Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck, Austria., pp. 3859–3865, Apr, 2012.
Link: http://dx.doi.org/10.1021/es204025y
Abstract
Mechanical wounding of plants triggers the release of a blend of reactive biogenic volatile organic compounds (BVOCs). During and after mowing and harvesting of managed grasslands, significant BVOC emissions have the potential to alter the physical and chemical properties of the atmosphere and lead to ozone and aerosol formation with consequences for regional air quality. We show that the amount and composition of BVOCs emitted per unit dry weight of plant material is comparable between laboratory enclosure measurements of artificially severed grassland plant species and in situ ecosystem-scale flux measurements above a temperate mountain grassland during and after periodic mowing and harvesting. The investigated grassland ecosystem emitted annually up to 130 mg carbon m(-2) in response to cutting and drying, the largest part being consistently represented by methanol and a blend of green leaf volatiles (GLV). In addition, we report the plant species-specific emission of furfural, terpenoid-like compounds (e.g., camphor), and sesquiterpenes from cut plant material, which may be used as tracers for the presence of given plant species in the ecosystem.
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[Graus2006] Graus, M., A. Hansel, A. Wisthaler, C. Lindinger, R. Forkel, K. Hauff, M. Klauer, A. Pfichner, B. Rappenglück, D. Steigner, et al., "A relaxed-eddy-accumulation method for the measurement of isoprenoid canopy-fluxes using an online gas-chromatographic technique and PTR-MS simultaneously", Atmospheric Environment, vol. 40: Elsevier, pp. 43–54, 2006.
Link: http://www.sciencedirect.com/science/article/pii/S1352231006003190
Abstract
A relaxed-eddy-accumulation set-up using an online gas-chromatographic technique and proton-transfer-reaction mass spectrometry was applied to determine isoprenoid fluxes above a Norway spruce forest in July 2001/2002. The system was quality assured and its suitability for determination of canopy fluxes of isoprenoids was demonstrated. Flux measurements of oxygenated hydrocarbons failed the data quality check due to artefacts presumably arising from line and ozone-scrubber effects. Observations of turbulent fluxes of isoprenoids during the two field experiments show good agreements with primary flux data derived from enclosure measurements and modelling results using a canopy-chemistry emission model (CACHE).
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[1511] Fares, S.., J.-H.. Park, D.. R. Gentner, R.. Weber, E.. Ormeᅢᄆo, J.. Karlik, and A.. H. Goldstein, "Seasonal cycles of biogenic volatile organic compound fluxes and concentrations in a California citrus orchard", Atmospheric Chemistry and Physics, vol. 12, pp. 9865–9880, Oct, 2012.
Link: http://dx.doi.org/10.5194/acp-12-9865-2012
Abstract
<p>Orange trees are widely cultivated in Mediterranean climatic regions where they are an important agricultural crop. Citrus have been characterized as emitters of volatile organic compounds (VOC) in chamber studies under controlled environmental conditions, but an extensive characterization at field scale has never been performed using modern measurement methods, and is particularly needed considering the complex interactions between the orchards and the polluted atmosphere in which Citrus is often cultivated. For one year, in a Valencia orange orchard in Exeter, California, we measured fluxes using PTRMS (Proton Transfer Reaction Mass Spectrometer) and eddy covariance for the most abundant VOC typically emitted from citrus vegetation: methanol, acetone, and isoprenoids. Concentration gradients of additional oxygenated and aromatic compounds from the ground level to above the canopy were also measured. In order to characterize concentrations of speciated biogenic VOC (BVOC) in leaves, we analyzed leaf content by GC-MS (Gas Chromatography &ndash; Mass Spectrometery) regularly throughout the year. We also characterized in more detail concentrations of speciated BVOC in the air above the orchard by in-situ GC-MS during a few weeks in spring flowering and summer periods. Here we report concentrations and fluxes of the main VOC species emitted by the orchard, discuss how fluxes measured in the field relate to previous studies made with plant enclosures, and describe how VOC content in leaves and emissions change during the year in response to phenological and environmental parameters. The orchard was a source of monoterpenes and oxygenated VOC. The highest emissions were observed during the springtime flowering period, with mid-day fluxes above 2 nmol m&minus;2 s&minus;1 for methanol and up to 1 nmol m&minus;2 s&minus;1 for acetone and monoterpenes. During hot summer days emissions were not as high as we expected considering the known dependence of biogenic emissions on temperature. We provide evidence that thickening of leaf cuticle wax content limited gaseous emissions during the summer.</p>
[1501] Holzinger, R.., A.. Lee, M.. McKay, and A.. H. Goldstein, "Seasonal variability of monoterpene emission factors for a ponderosa pine plantation in California", Atmospheric Chemistry and Physics, vol. 6, pp. 1267–1274, Apr, 2006.
Link: http://nature.berkeley.edu/ahg/pubs/seasonal.pdf
Abstract
<p>Monoterpene fluxes have been measured over an 11 month period from June 2003 to April 2004. During all seasons ambient air temperature was the environmental factor most closely related to the measured emission rates. The monoterpene flux was modeled using a basal emission rate multiplied by an exponential function of a temperature, following the typical practice for modelling temperature dependent biogenic emissions. A basal emission of 1.0 μmol h&minus;1 m&minus;2 (at 30&deg;C, based on leaf area) and a temperature dependence (β) of 0.12&deg;C&minus;1 reproduced measured summer emissions well but underestimated spring and winter measured emissions by 60&ndash;130%. The total annual monoterpene emission may be underestimated by &nbsp;50% when using a model optimized to reproduce monoterpene emissions in summer. The long term dataset also reveals an indirect connection between non-stomatal ozone and monoterpene flux beyond the dependence on temperature that has been shown for both fluxes.</p>
[Karl2003c] Karl, T., A. Guenther, C. Spirig, A. Hansel, and R. Fall, "Seasonal variation of biogenic VOC emissions above a mixed hardwood forest in northern Michigan", Geophysical Research Letters, vol. 30, no. 23: Wiley Online Library, 2003.
Link: http://onlinelibrary.wiley.com/doi/10.1029/2003GL018432/full
Abstract
Fluxes of biogenic volatile organic compounds (VOCs) were measured at a hardwood forest in northern Michigan (UMBS, Prophet research site) over the course of the growing and senescing season. Methanol, acetaldehyde, acetone and isoprene were found to be the most abundant biogenic VOCs with maximum fluxes (mixing ratios in ppbv) of 2.0 mg m−2 h−1 (21.0), 1.0 mg m−2 h−1 (2.7), 1.6 mg m−2 h−1 (5.6) and 7.6 mg m−2 h−1 (6), respectively. The emission patterns show distinct seasonal changes and indicate a spring peak for methanol due to rapid leaf expansion and a fall peak for acetone and acetaldehyde most likely attributed to senescing and decaying biomass; isoprene emissions peaked as expected in the summer. We estimate potential source strengths of 8.9 Tg (C) y−1 methanol, 2.7 Tg (C) y−1 acetaldehyde and 7.0 Tg (C) y−1 acetone for deciduous temperate forests, which is a substantial contribution to the global atmospheric VOC budget.
[1521] Brilli, F., B. Gioli, D. Zona, E. Pallozzi, T. Zenone, G. Fratini, C. Calfapietra, F. Loreto, I. A. Janssens, and R. Ceulemans, "Simultaneous leaf- and ecosystem-level fluxes of volatile organic compounds from a poplar-based SRC plantation", Agricultural and Forest Meteorology, vol. 187, pp. 22–35, Apr, 2014.
Link: http://dx.doi.org/10.1016/j.agrformet.2013.11.006
Abstract
<p>Emission of carbon from ecosystems in the form of volatile organic compounds (VOC) represents a minorcomponent flux in the global carbon cycle that has a large impact on ground-level ozone, particle andaerosol formation and thus on air chemistry and quality. This study reports exchanges of CO2and VOCbetween a poplar-based short rotation coppice (SRC) plantation and the atmosphere, measured simul-taneously at two spatial scale, one at stand level and another at leaf level. The first technique combinedProton Transfer Reaction &ldquo;Time-of-Flight&rdquo; mass spectrometry (PTR&ndash;TOF&ndash;MS) with the eddy covariancemethod, to measure fluxes of a multitude of VOC. Abundant fluxes of isoprene, methanol and, to a lesserextent, fluxes of other oxygenated VOC such as formaldehyde, isoprene oxidation products (methyl vinylketone and methacrolein), methyl ethyl ketone, acetaldehyde, acetone and acetic acid, were measured.Under optimal environmental conditions, isoprene flux was mostly controlled by temperature and light.Differently, methanol flux underwent a combined enzymatic and stomatal control, together involvingenvironmental drivers such as vapour pressure deficit (VPD), temperature and light intensity. Moreoverfair weather condition favoured ozone deposition to the poplar plantation.The second technique involved trapping the VOCs emitted from leaves followed by gaschromatography-mass spectrometry (GC&ndash;MS) analysis. These leaf-level measurements showed thatemission of isoprene in adult leaves and of monoterpenes in juvenile leaves are widespread across poplargenotypes. Detection of isoprene oxidation products (iox) emission with leaf-level measurements con-firmed that a fraction of isoprene may be already oxidized within leaves, possibly when isoprene copeswith foliar reactive oxygen species (ROS) formed during warm and sunny days.</p>
T
[Ammann2006] Ammann, C., A. Brunner, C. Spirig, and A. Neftel, "Technical note: Water vapour concentration and flux measurements with PTR-MS", Atmospheric Chemistry and Physics, vol. 6, no. 12: Copernicus GmbH, pp. 4643–4651, 2006.
Link: http://www.atmos-chem-phys.net/6/4643/2006/acp-6-4643-2006.pdf
[1818] Schallhart, S., P. Rantala, M. K. Kajos, J. Aalto, I. Mammarella, T. M. Ruuskanen, and M. Kulmala, "Temporal variation of {VOC} fluxes measured with {PTR}-{TOF} above a boreal forest", Atmospheric Chemistry and Physics Discussions, pp. 1–29, jun, 2017.
Abstract
<p>Between April and June 2013 fluxes of volatile organic compounds (VOCs) were measured in a Scots pine and Norway spruce forest using the eddy covariance (EC) method with a proton transfer reaction time of flight (PTR-TOF) mass spectrometer. The observations were performed above a boreal forest at the SMEAR II site in Southern Finland. We found a total of 25 different compounds with exchange and investigated their seasonal variations from spring to summer. The majority of the net VOC flux was comprised of methanol, monoterpenes, acetone and butene. The VOC emissions followed a seasonal trend, the released amount increased from spring to summer. Only a three compounds were emitted in April while in June emissions of some 19 VOCs were observed. During the measurements in April, the emissions were dominated by butene, while in May and June methanol was the most emitted compound. The main source of methanol is likely the growth of new biomass. During a 21-day period in June, the net VOC flux was 2.3&thinsp;nmol&thinsp;m&minus;2&thinsp;s&minus;1. This is on the lower end of PTR-TOF flux measurements from other ecosystems, which range from 2 to 10&thinsp;nmol&thinsp;m&minus;2&thinsp;s&minus;1. The EC flux results were compared with surface layer profile measurements, an indirect method using a proton transfer reaction quadrupole mass spectrometer, which is permanently installed at the SMEAR II site was used. For most of the compounds the fluxes, measured with the two different methods, agreed well.</p>
[1759] Greenberg, J.. P., J.. Penuelas, A.. Guenther, R.. Seco, A.. Turnipseed, X.. Jiang, I.. Filella, M.. Estiarte, J.. Sardans, R.. Ogaya, et al., "A tethered-balloon PTRMS sampling approach for surveying of landscape-scale biogenic VOC fluxes", Atmospheric Measurement Techniques, vol. 7, pp. 2263–2271, Jul, 2014.
Link: http://dx.doi.org/10.5194/amt-7-2263-2014
Abstract
<p>To survey landscape-scale fluxes of biogenic gases, a 100 m Teflon tube was attached to a tethered balloon as a sampling inlet for a fast response Proton Transfer Reaction Mass Spectrometer (PTRMS). Along with meteorological instruments deployed on the tethered balloon and at 3 m and outputs from a regional weather model, these observations were used to estimate landscape scale biogenic volatile organic compound fluxes with two micrometeorological techniques: mixed layer variance and surface layer gradients. This highly mobile sampling system was deployed at four field sites near Barcelona to estimate landscape-scale BVOC emission factors in a relatively short period (3 weeks). The two micrometeorological techniques agreed within the uncertainty of the flux measurements at all four sites even though the locations had considerable heterogeneity in species distribution and complex terrain. The observed fluxes were significantly different than emissions predicted with an emission model using site-specific emission factors and land-cover characteristics. Considering the wide range in reported BVOC emission factors of VOCs for individual vegetation species (more than an order of magnitude), this flux estimation technique is useful for constraining BVOC emission factors used as model inputs.</p>
[Forkel2006] Forkel, R., O. Klemm, M. Graus, B. Rappenglück, W. R. Stockwell, W. Grabmer, A. Held, A. Hansel, and R. Steinbrecher, "Trace gas exchange and gas phase chemistry in a Norway spruce forest: A study with a coupled 1-dimensional canopy atmospheric chemistry emission model", Atmospheric Environment, vol. 40: Elsevier, pp. 28–42, 2006.
Link: http://www.sciencedirect.com/science/article/pii/S1352231006003189
Abstract
Numerical modelling is an efficient tool to investigate the role of chemical degradation of biogenic volatile organic compounds (BVOC) and the effect of dynamical processes on BVOC and product mixing ratios within and above forest canopies. The present study shows an application of the coupled canopy-chemistry model CACHE to a Norway spruce forest at the Waldstein (Fichtelgebirge, Germany). Simulated courses of temperature, trace gas mixing ratios, and fluxes are compared with measurements taken during the BEWA2000 field campaigns. The model permits the interpretation of the observed diurnal course of ozone and VOC by investigating the role of turbulent exchange, chemical formation and degradation, emission, and deposition during the course of the day. The simulation results show that BVOC fluxes into the atmosphere are 10–15% lower than the emission fluxes on branch basis due to chemical BVOC degradation within the canopy. BVOC degradation by the NO3 radical was found to occur in the lower part of the canopy also during daytime. Furthermore, the simulations strongly indicate that further research is still necessary concerning the emission and deposition of aldehydes and ketones.

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Selected PTR-MS related Reviews

F. Biasioli, C. Yeretzian, F. Gasperi, T. D. Märk: PTR-MS monitoring of VOCs and BVOCs in food science and technology, Trends in Analytical Chemistry 30 (7) (2011).
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J. de Gouw, C. Warneke, T. Karl, G. Eerdekens, C. van der Veen, R. Fall: Measurement of Volatile Organic Compounds in the Earth's Atmosphere using Proton-Transfer-Reaction Mass Spectrometry. Mass Spectrometry Reviews, 26 (2007), 223-257.
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W. Lindinger, A. Hansel, A. Jordan: Proton-transfer-reaction mass spectrometry (PTR–MS): on-line monitoring of volatile organic compounds at pptv levels, Chem. Soc. Rev. 27 (1998), 347-375.
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Lists with PTR-MS relevant publications of the University of Innsbruck can be found here: Atmospheric and indoor air chemistry, IMR, Environmental Physics and Nano-Bio-Physics

 

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