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Scientific Articles - PTR-MS Bibliography

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A
[Ngwabie2008] Ngwabie, N. Martin, G. W. Schade, T. G. Custer, S. Linke, and T. Hinz, "Abundances and flux estimates of volatile organic compounds from a dairy cowshed in Germany", Journal of environmental quality, vol. 37, no. 2: American Society of Agronomy, Crop Science Society of America, Soil Science Society, pp. 565–573, 2008.
Link: https://dl.sciencesocieties.org/publications/jeq/abstracts/37/2/565
Abstract
Animal husbandry and manure treatment have been specifically documented as significant sources of methane, ammonia, nitrous oxide, and particulate matter. Although volatile organic compounds (VOCs) are also produced, much less information exists concerning their impact. We report on chemical ionization mass spectrometry and photo-acoustic spectroscopy measurements of mixing ratios of VOCs over a 2-wk measurement period in a large cowshed at the Federal Agricultural Research Centre (FAL) in Mariensee, Germany. The high time resolution of these measurements enables insight into the sources of the emissions in a typical livestock management setting. During feeding hours and solid manure removal, large mixing ratio spikes of several VOCs were observed and correlated with simultaneous methane, carbon dioxide, and ammonia level enhancements. The subsequent decay of cowshed concentration due to passive cowshed ventilation was used to model emission rates, which were dominated by ethanol and acetic acid, followed by methanol. Correlations of VOC mixing ratios with methane or ammonia were also used to calculate cowshed emission factors and to estimate potential nationwide VOC emissions from dairy cows. The results ranged from around 0.1 Gg carbon per year (1 Gg = 109 g) for nonanal and dimethylsulfide, several Gg carbon per year for volatile fatty acids and methanol, to over 10 Gg carbon per year of emitted ethanol. While some estimates were not consistent between the two extrapolation methods, the results indicate that animal husbandry VOC emissions are dominated by oxygenated compounds and may be a nationally but not globally significant emission to the atmosphere.
[Park2013] Park, J-H.., A.. H. Goldstein, J.. Timkovsky, S.. Fares, R.. Weber, J.. Karlik, and R.. Holzinger, "Active atmosphere-ecosystem exchange of the vast majority of detected volatile organic compounds.", Science, vol. 341, no. 6146: Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, CA 94720, USA., pp. 643–647, Aug, 2013.
Link: http://nature.berkeley.edu/ahg/pubs/Park%20et%20al%20Science%202013.pdf
Abstract
<p>Numerous volatile organic compounds (VOCs) exist in Earth&#39;s atmosphere, most of which originate from biogenic emissions. Despite VOCs&#39; critical role in tropospheric chemistry, studies for evaluating their atmosphere-ecosystem exchange (emission and deposition) have been limited to a few dominant compounds owing to a lack of appropriate measurement techniques. Using a high-mass resolution proton transfer reaction-time of flight-mass spectrometer and an absolute value eddy-covariance method, we directly measured 186 organic ions with net deposition, and 494 that have bidirectional flux. This observation of active atmosphere-ecosystem exchange of the vast majority of detected VOCs poses a challenge to current emission, air quality, and global climate models, which do not account for this extremely large range of compounds. This observation also provides new insight for understanding the atmospheric VOC budget.</p>
[1516] Misztal, P.. K., T.. Karl, R.. Weber, H.. H. Jonsson, A.. B. Guenther, and A.. H. Goldstein, "Airborne flux measurements of biogenic volatile organic compounds over California", Atmospheric Chemistry and Physics Discussions, vol. 14, pp. 7965–8013, Mar, 2014.
Link: http://www.atmos-chem-phys-discuss.net/14/7965/2014/acpd-14-7965-2014.html
Abstract
<p>Biogenic Volatile Organic Compound (BVOC) fluxes were measured onboard the CIRPAS Twin Otter aircraft as part of the California Airborne BVOC Emission Research in Natural Ecosystem Transects (CABERNET) campaign during June 2011. The airborne virtual disjunct eddy covariance (AvDEC) approach used measurements from a PTR-MS and a wind radome probe to directly determine fluxes of isoprene, MVK + MAC, methanol, monoterpenes, and MBO over 10 000 km of flight paths focusing on areas of California predicted to have the largest emissions of isoprene. The Fast Fourier Transform (FFT) approach was used to calculate fluxes over long transects of more than 15 km, most commonly between 50 and 150 km. The Continuous Wavelet Transformation (CWT) approach was used over the same transects to also calculate &quot;instantaneous&quot; fluxes with localization of both frequency and time independent of non-stationarities. Vertical flux divergence of isoprene is expected due to its relatively short lifetime and was measured directly using &quot;racetrack&quot; profiles at multiple altitudes. It was found to be linear and in the range 5% to 30% depending on the ratio of aircraft altitude to PBL height (z / zi). Fluxes were generally measured by flying consistently at 400 &plusmn; 50 m (a.g.l.) altitude, and extrapolated to the surface according to the determined flux divergence. The wavelet-derived surface fluxes of isoprene averaged to 2 km spatial resolution showed good correspondence to Basal Emission Factor (BEF) landcover datasets used to drive biogenic VOC (BVOC) emission models. The surface flux of isoprene was close to zero over Central Valley crops and desert shrublands, but was very high (up to 15 mg m&minus;2 h&minus;1) above oak woodlands, with clear dependence of emissions on temperature and oak density. Isoprene concentrations of up to 8 ppb were observed at aircraft height on the hottest days and over the dominant source regions. While isoprene emissions from agricultural crop regions, shrublands, and coniferous forests were extremely low, high concentrations of methanol and monoterpenes were found above some of these regions. These observations demonstrate the ability to measure fluxes from specific sources by eddy covariance from an aircraft, and suggest the utility of measurements using fast response chemical sensors to constrain emission inventories and map out source distributions for a much broader array of trace gases than was observed in this study. This paper reports the first regional direct eddy covariance fluxes of isoprene. The emissions of VOCs measured from aircraft with 2 km spatial resolution can quantify the distribution of major sources providing the observations required for testing statewide emission inventories of these important trace gases. These measurements will be used in a future study to assess BVOC emission models and their driving variable datasets.</p>
[1514] Karl, T.., P.. K. Misztal, H.. H. Jonsson, S.. Shertz, A.. H. Goldstein, and A.. B. Guenther, "Airborne Flux Measurements of BVOCs above Californian Oak Forests: Experimental Investigation of Surface and Entrainment Fluxes, OH Densities, and Damköhler Numbers", J. Atmos. Sci., vol. 70, pp. 3277–3287, Oct, 2013.
Link: http://nature.berkeley.edu/ahg/pubs/Karl et al 2013 JAS.pdf
Abstract
<p>Airborne flux measurements of isoprene were performed over the Californian oak belts surrounding the Central Valley. The authors demonstrate for the first time 1) the feasibility of airborne eddy covariance measurements of reactive biogenic volatile organic compounds; 2) the effect of chemistry on the vertical transport of reactive species, such as isoprene; and 3) the applicability of wavelet analysis to estimate regional fluxes of biogenic volatile organic compounds. These flux measurements demonstrate that instrumentation operating at slower response times (e.g., 1&ndash;5 s) can still be used to determine eddy covariance fluxes in the mixed layer above land, where typical length scales of 0.5&ndash;3 km were observed. Flux divergence of isoprene measured in the planetary boundary layer (PBL) is indicative of OH densities in the range of 4&ndash;7 &times; 106 molecules per cubic centimeter and allows extrapolation of airborne fluxes to the surface with Damköhler numbers (ratio between the mixing time scale and the chemical time scale) in the range of 0.3&ndash;0.9. Most of the isoprene is oxidized in the PBL with entrainment fluxes of about 10% compared to the corresponding surface fluxes. Entrainment velocities of 1&ndash;10 cm s&minus;1 were measured. The authors present implications for parameterizing PBL schemes of reactive species in regional and global models.</p>
[Sinha2007] Sinha, V., J. Williams, M. Meyerhöfer, U. Riebesell, AI. Paulino, and A. Larsen, "Air-sea fluxes of methanol, acetone, acetaldehyde, isoprene and DMS from a Norwegian fjord following a phytoplankton bloom in a mesocosm experiment", Atmospheric Chemistry and Physics, vol. 7, no. 3: Copernicus GmbH, pp. 739–755, 2007.
Link: http://www.atmos-chem-phys.net/7/739/2007/acp-7-739-2007.html
Abstract
{The ocean's influence on volatile organic compounds (VOCs) in the atmosphere is poorly understood. This work characterises the oceanic emission and/or uptake of methanol, acetone, acetaldehyde, isoprene and dimethyl sulphide (DMS) as a function of photosynthetically active radiation (PAR) and a suite of biological parameters. The measurements were taken following a phytoplankton bloom, in May/June 2005 with a proton transfer reaction mass spectrometer (PTR-MS), from mesocosm enclosures anchored in the Raunefjord, Southern Norway. The net flux of methanol was always into the ocean, and was stronger at night. Isoprene and acetaldehyde were emitted from the ocean, correlating with light (ravcorr
[1582] Beale, R., J. L. Dixon, T. J. Smyth, and P. D. Nightingale, "Annual study of oxygenated volatile organic compounds in UK shelf waters", Marine Chemistry, vol. 171, pp. 96¬106, Apr, 2015.
Link: http://dx.doi.org/10.1016/j.marchem.2015.02.013
Abstract
We performed an annual study of oxygenated volatile organic compound (OVOC) seawater concentrations at a site off Plymouth, UK in the Western English Channel over the period of February 2011–March 2012. Acetone concentrations ranged from 2–10 nM (nanomole/L) in surface waters with a maximum observed in summer. Concentrations correlated positively with net shortwave radiation and UV light, suggestive of photochemically linked acetone production. We observed a clear decline in acetone concentrations below the mixed layer. Acetaldehyde varied between 4–37 nM in surface waters with higher values observed in autumn and winter. Surface concentrations of methanol ranged from 16–78 nM, but no clear annual cycle was observed. Methanol concentrations exhibited considerable inter-annual variability. We estimate consistent deposition to the sea surface for acetone and methanol but that the direction of the acetaldehyde flux varies during the year
[1443] Veres, P. R., P. Faber, F. Drewnick, J. Lelieveld, and J. Williams, "Anthropogenic sources of VOC in a football stadium: Assessing Human Emissions in the Atmosphere", Atmospheric Environment, 2013.
Link: http://www.sciencedirect.com/science/article/pii/S1352231013004494
Abstract
<p>Measurements of gas-phase volatile organic compounds (VOCs), aerosol composition, carbon dioxide (CO2), and ozone (O3) were made inside Coface Arena in Mainz, Germany (49&deg;59&prime;3&Prime;N, 8&deg;13&prime;27&Prime;E) during a football match on April 20 2012. The VOC measurements were performed with a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS). Observed VOCs could be classified into several distinct source categories including (1) human respiration/breath, (2) ozonolysis of skin oils, and (3) cigarette smoke/combustion. In this work, we present a detailed discussion on the scale and potential impacts of VOCs emitted as a result of these sources and their contributions on local and larger scales. Human emissions of VOCs have a negligible contribution to the global atmospheric budget (&sim;1% or less) for all those quantified in this study. However, fluxes as high as 0.02 g m&minus;2 h&minus;1 and 2 &times; 10&minus;4 g m&minus;2 h&minus;1, for ethanol and acetone respectively are observed, suggesting the potential for significant impact on local air chemistry and perhaps regional scales. This study suggests that even in outdoor environments, situations exist where VOCs emitted as a result of human presence and activity are an important component of local air chemistry.</p>
[1612] Feilberg, A., P. Bildsoe, and T. Nyord, "Application of PTR-MS for measuring odorant emissions from soil application of manure slurry.", Sensors (Basel), vol. 15, pp. 1148–1167, 2015.
Link: http://dx.doi.org/10.3390/s150101148
Abstract
<p>Odorous volatile organic compounds (VOC) and hydrogen sulfide (H2S) are emitted together with ammonia (NH3) from manure slurry applied as a fertilizer, but little is known about the composition and temporal variation of the emissions. In this work, a laboratory method based on dynamic flux chambers packed with soil has been used to measure emissions from untreated pig slurry and slurry treated by solid-liquid separation and ozonation. Proton-transfer-reaction mass spectrometry (PTR-MS) was used to provide time resolved data for a range of VOC, NH3 and H2S. VOC included organic sulfur compounds, carboxylic acids, phenols, indoles, alcohols, ketones and aldehydes. H2S emission was remarkably observed to take place only in the initial minutes after slurry application, which is explained by its high partitioning into the air phase. Long-term odor effects are therefore assessed to be mainly due to other volatile compounds with low odor threshold values, such as 4-methylphenol. PTR-MS signal assignment was verified by comparison to a photo-acoustic analyzer (NH3) and to thermal desorption GC/MS (VOC). Due to initial rapid changes in odorant emissions and low concentrations of odorants, PTR-MS is assessed to be a very useful method for assessing odor following field application of slurry. The effects of treatments on odorant emissions are discussed.</p>
[1497] Yang, M.., P.. D. Nightingale, R.. Beale, P.. S. Liss, B.. Blomquist, and C.. Fairall, "Atmospheric deposition of methanol over the Atlantic Ocean", Proceedings of the National Academy of Sciences, vol. 110, pp. 20034–20039, Dec, 2013.
Link: http://dx.doi.org/10.1073/pnas.1317840110
Abstract
<p>In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air&ndash;sea methanol transfer along a &sim;10,000-km north&ndash;south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air&ndash;sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at &sim;5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface&mdash;an important term for improving air&ndash;sea gas exchange models.</p>
B
[Ghirardo2011] Ghirardo, A., J. Gutknecht, I. Zimmer, N. Brueggemann, and J-P. Schnitzler, "Biogenic volatile organic compound and respiratory CO2 emissions after 13C-labeling: online tracing of C translocation dynamics in poplar plants.", PLoS One, vol. 6, no. 2: Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Garmisch-Partenkirchen, Germany., pp. e17393, 2011.
Link: http://dx.doi.org/10.1371/journal.pone.0017393
Abstract
Globally plants are the primary sink of atmospheric CO(2), but are also the major contributor of a large spectrum of atmospheric reactive hydrocarbons such as terpenes (e.g. isoprene) and other biogenic volatile organic compounds (BVOC). The prediction of plant carbon (C) uptake and atmospheric oxidation capacity are crucial to define the trajectory and consequences of global environmental changes. To achieve this, the biosynthesis of BVOC and the dynamics of C allocation and translocation in both plants and ecosystems are important.We combined tunable diode laser absorption spectrometry (TDLAS) and proton transfer reaction mass spectrometry (PTR-MS) for studying isoprene biosynthesis and following C fluxes within grey poplar (Populus x canescens) saplings. This was achieved by feeding either (13)CO(2) to leaves or (13)C-glucose to shoots via xylem uptake. The translocation of (13)CO(2) from the source to other plant parts could be traced by (13)C-labeled isoprene and respiratory (13)CO(2) emission.In intact plants, assimilated (13)CO(2) was rapidly translocated via the phloem to the roots within 1 hour, with an average phloem transport velocity of 20.3 ± 2.5 cm h(-1). (13)C label was stored in the roots and partially reallocated to the plants' apical part one day after labeling, particularly in the absence of photosynthesis. The daily C loss as BVOC ranged between 1.6% in mature leaves and 7.0% in young leaves. Non-isoprene BVOC accounted under light conditions for half of the BVOC C loss in young leaves and one-third in mature leaves. The C loss as isoprene originated mainly (76-78%) from recently fixed CO(2), to a minor extent from xylem-transported sugars (7-11%) and from photosynthetic intermediates with slower turnover rates (8-11%).We quantified the plants' C loss as respiratory CO(2) and BVOC emissions, allowing in tandem with metabolic analysis to deepen our understanding of ecosystem C flux.
[1515] Park, J.-H.., S.. Fares, R.. Weber, and A.. H. Goldstein, "Biogenic volatile organic compound emissions during BEARPEX 2009 measured by eddy covariance and flux-gradient similarity methods", Atmospheric Chemistry and Physics, vol. 14, pp. 231–244, Jan, 2014.
Link: http://nature.berkeley.edu/ahg/pubs/Park et al-acp-14-231-2014.pdf
Abstract
<p>The Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX) took place in Blodgett Forest, a Ponderosa pine forest in the Sierra Nevada of California, USA, during summer 2009. We deployed a proton transfer reaction&ndash;quadrupole mass spectrometer (PTR-QMS) to measure fluxes and concentrations of biogenic volatile organic compounds (BVOCs). Eighteen ion species, including the major BVOC expected at the site, were measured sequentially at 5 heights to observe their vertical gradient from the forest floor to above the canopy. Fluxes of the 3 dominant BVOCs methanol, 2-Methyl-3-butene-2-ol (MBO), and monoterpenes were measured above the canopy by the disjunct eddy covariance (EC) method. Canopy-scale fluxes were also determined by the flux&ndash;gradient similarity method (K-theory). A universal K (Kuniv) was determined as the mean of individual K&#39;s calculated from the measured fluxes divided by vertical gradients for methanol, MBO, and monoterpenes. This Kuniv was then multiplied by the gradients of each observed ion species to compute their fluxes. The flux&ndash;gradient similarity method showed very good agreement with the disjunct EC method. Fluxes are presented for all measured species and compared to historical measurements from the same site, and used to test emission algorithms used to model fluxes at the regional scale. MBO was the dominant emission observed, followed by methanol, monoterpenes, acetone, and acetaldehyde. The flux&ndash;gradient similarity method is shown to be tenable, and we recommend its use, especially in experimental conditions when fast measurement of BVOC species is not available.</p>
[1587] Hörtnagl, L., I. Bamberger, M. Graus, T. M. Ruuskanen, R. Schnitzhofer, M. Müller, A. Hansel, and G. Wohlfahrt, "Biotic, abiotic and management controls on methanol exchange above a temperate mountain grassland.", J Geophys Res Biogeosci, vol. 116, Sep, 2011.
Link: http://dx.doi.org/10.1029/2011jg001641
Abstract
<p>Methanol (CH3OH) fluxes were quantified above a managed temperate mountain grassland in the Stubai Valley (Tyrol, Austria) during the growing seasons 2008 and 2009. Half-hourly methanol fluxes were calculated by means of the virtual disjunct eddy covariance (vDEC) method using 3-dimensional wind data from a sonic anemometer and methanol volume mixing ratios measured with a proton-transfer-reaction mass spectrometer (PTR-MS). During (undisturbed) mature and growing phases methanol fluxes exhibited a clear diurnal cycle with close-to-zero fluxes during nighttime and emissions, up to 10 nmol m(-2) s(-1), which followed the diurnal course of radiation and air temperature. Management events were found to represent the largest perturbations of methanol exchange at the studied grassland ecosystem: Peak emissions of 144.5 nmol m(-2) s(-1) were found during/after cutting of the meadow reflecting the wounding of the plant material and subsequent depletion of the leaf internal aqueous methanol pools. After the application of organic fertilizer, elevated methanol emissions of up to 26.7 nmol m(-2) s(-1) were observed, likely reflecting enhanced microbial activity associated with the applied manure. Simple and multiple linear regression analyses revealed air temperature and radiation as the dominant abiotic controls, jointly explaining 47 % and 70 % of the variability in half-hourly and daily methanol fluxes. In contrast to published leaf-level laboratory studies, the surface conductance and the daily change in the amount of green plant area, used as ecosystem-scale proxies for stomatal conductance and growth, respectively, were found to exert only minor biotic controls on methanol exchange.</p>
[1585] Bamberger, I.., L.. Hortnagl, R.. Schnitzhofer, M.. Graus, T.. M. Ruuskanen, M.. Muller, J.. Dunkl, G.. Wohlfahrt, and A.. Hansel, "BVOC fluxes above mountain grassland.", Biogeosciences, vol. 7, May, 2010.
Link: http://www.biogeosciences.net/7/1413/2010/bg-7-1413-2010.html
Abstract
<p>Grasslands comprise natural tropical savannah over managed temperate fields to tundra and cover one quarter of the Earth&#39;s land surface. Plant growth, maintenance and decay result in volatile organic compound (VOCs) emissions to the atmosphere. Furthermore, biogenic VOCs (BVOCs) are emitted as a consequence of various environmental stresses including cutting and drying during harvesting. Fluxes of BVOCs were measured with a proton-transfer-reaction-mass-spectrometer (PTR-MS) over temperate mountain grassland in Stubai Valley (Tyrol, Austria) over one growing season (2008). VOC fluxes were calculated from the disjunct PTR-MS data using the virtual disjunct eddy covariance method and the gap filling method. Methanol fluxes obtained with the two independent flux calculation methods were highly correlated (y = 0.95&times;-0.12, R (2) = 0.92). Methanol showed strong daytime emissions throughout the growing season - with maximal values of 9.7 nmol m(-2) s(-1), methanol fluxes from the growing grassland were considerably higher at the beginning of the growing season in June compared to those measured during October (2.5 nmol m(-2) s(-1)). Methanol was the only component that exhibited consistent fluxes during the entire growing periods of the grass. The cutting and drying of the grass increased the emissions of methanol to up to 78.4 nmol m(-2) s(-1). In addition, emissions of acetaldehyde (up to 11.0 nmol m(-2) s(-1)), and hexenal (leaf aldehyde, up to 8.6 nmol m(-2) s(-1)) were detected during/after harvesting.</p>
[Bamberger2010] Bamberger, I., L. Hörtnagl, R. Schnitzhofer, M. Graus, TM. Ruuskanen, M. Müller, J. Dunkl, G. Wohlfahrt, and A. Hansel, "BVOC fluxes above mountain grassland", Biogeosciences, vol. 7, no. 5: Copernicus GmbH, pp. 1413–1424, 2010.
Link: http://www.biogeosciences.net/7/1413/2010/bg-7-1413-2010.pdf
C
[Herndon2005] Herndon, S. C., J. T. Jayne, M. S. Zahniser, D. R. Worsnop, B. Knighton, E. Alwine, B. K. Lamb, M. Zavala, D. D. Nelson, B. J McManus, et al., "Characterization of urban pollutant emission fluxes and ambient concentration distributions using a mobile laboratory with rapid response instrumentation", Faraday Discussions, vol. 130: Royal Society of Chemistry, pp. 327–339, 2005.
Link: http://pubs.rsc.org/en/content/articlehtml/2005/fd/b500411j
Abstract
A large and increasing fraction of the planet’s population lives in megacities, especially in the developing world. These large metropolitan areas generally have very high levels of both gaseous and particulate air pollutants that have severe impacts on human health, ecosystem viability, and climate on local, regional, and even continental scales. Emissions fluxes and ambient pollutant concentration distributions are generally poorly characterized for large urban areas even in developed nations. Much less is known about pollutant sources and concentration patterns in the faster growing megacities of the developing world. New methods of locating and measuring pollutant emission sources and tracking subsequent atmospheric chemical transformations and distributions are required. Measurement modes utilizing an innovative van based mobile laboratory equipped with a suite of fast response instruments to characterize the complex and “nastier” chemistry of the urban boundary layer are described. Instrumentation and measurement strategies are illustrated with examples from the Mexico City and Boston metropolitan areas. It is shown that fleet average exhaust emission ratios of formaldehyde (HCHO), acetaldehyde (CH3CHO) and benzene (C6H6) are substantial in Mexico City, with gasoline powered vehicles emitting higher levels normalized by fuel consumption. NH3 exhaust emissions from newer light duty vehicles in Mexico City exceed levels from similar traffic in Boston. A mobile conditional sampling air sample collection mode designed to collect samples from intercepted emission plumes for later analysis is also described.
[FeilbergTavsNyord2011] Nyord}, A. {Feilberg, M. N. Ã. ¸rrega Hansen, and S. Lindholst, "Chemical evaluation of odor reduction by soil injection of animal manure.", J Environ Qual, vol. 40, no. 5: Dep. of Biosystem Engineering, Faculty of Science and Technology, Aarhus Univ., Denmark. anders.feilberg@agrsci.dk, pp. 1674–1682, 2011.
Link: http://dx.doi.org/10.2134/jeq2010.0499
Abstract
Field application of animal manure is a major cause of odor nuisance in the local environment. Therefore, there is a need for methods for measuring the effect of technologies for reducing odor after manure application. In this work, chemical methods were used to identify key odorants from field application of pig manure based on experiments with surface application by trailing hoses and soil injection. Results from three consecutive years of field trials with full-scale equipment are reported. Methods applied were: membrane inlet mass spectrometry (MIMS), proton-transfer-reaction mass spectrometry (PTR-MS), gold-film hydrogen sulfide (H?S) detection, all performed on site, and thermal desorption gas chromatography with mass spectrometry (TD-GC/MS) based on laboratory analyses of field samples. Samples were collected from a static flux chamber often used for obtaining samples for dynamic olfactometry. While all methods were capable of detecting relevant odorants, PTR-MS gave the most comprehensive results. Based on odor threshold values, 4-methylphenol, H?S, and methanethiol are suggested as key odorants. Significant odorant reductions by soil injection were consistently observed in all trials. The flux chamber technique was demonstrated to be associated with critical errors due to compound instabilities in the chamber. This was most apparent for H?S, on a time scale of a few minutes, and on a longer time scale for methanethiol.
[Karl2008] Karl, T., A. Guenther, A. Turnipseed, EG. Patton, K. Jardine, and , "Chemical sensing of plant stress at the ecosystem scale", Biogeosciences Discussions, vol. 5, no. 3, pp. 2381–2399, 2008.
Link: http://hal.archives-ouvertes.fr/hal-00298013/
Abstract
Significant ecosystem-scale emissions of methylsalicylate (MeSA), a semivolatile plant hormone thought to act as the mobile signal for systemic acquired resistance (SAR) (Park et al., 2006), were observed in an agroforest. Our measurements show that plant internal defence mechanisms can be activated in response to temperature stress and are modulated by water availability on large scales. Highest MeSA fluxes (up to 0.25 mg/m2/h) were observed after plants experienced ambient night-time temperatures of  7.5°C followed by a large daytime temperature increase (e.g. up to 22°C). Under these conditions estimated night-time leaf temperatures were as low as  4.6°C, likely inducing a response to prevent chilling injury (Ding et al., 2002). Our observations imply that plant hormones can be a significant component of ecosystem scale volatile organic compound (VOC) fluxes (e.g. as high as the total monoterpene (MT) flux) and therefore contribute to the missing VOC budget (de Carlo et al., 2004; Goldstein and Galbally, 2007). If generalized to other ecosystems and different types of stresses these findings suggest that semivolatile plant hormones have been overlooked by investigations of the impact of biogenic VOCs on aerosol formation events in forested regions (Kulmala et al., 2001; Boy et al., 2000). Our observations show that the presence of MeSA in canopy air serves as an early chemical warning signal indicating ecosystem-scale stresses before visible damage becomes apparent. As a chemical metric, ecosystem emission measurements of MeSA in ambient air could therefore support field studies investigating factors that adversely affect plant growth.
[1506] Wolfe, G.. M., J.. A. Thornton, N.. C. Bouvier-Brown, A.. H. Goldstein, J.-H.. Park, M.. McKay, D.. M. Matross, J.. Mao, W.. H. Brune, B.. W. LaFranchi, et al., "The Chemistry of Atmosphere-Forest Exchange (CAFE) Model ¬タモ Part 2: Application to BEARPEX-2007 observations", Atmospheric Chemistry and Physics, vol. 11, pp. 1269–1294, Feb, 2011.
Link: http://nature.berkeley.edu/ahg/pubs/Wolf et al acp-11-1269-2011.pdf
Abstract
<p>In a companion paper, we introduced the Chemistry of Atmosphere-Forest Exchange (CAFE) model, a vertically-resolved 1-D chemical transport model designed to probe the details of near-surface reactive gas exchange. Here, we apply CAFE to noontime observations from the 2007 Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX-2007). In this work we evaluate the CAFE modeling approach, demonstrate the significance of in-canopy chemistry for forest-atmosphere exchange and identify key shortcomings in the current understanding of intra-canopy processes. CAFE generally reproduces BEARPEX-2007 observations but requires an enhanced radical recycling mechanism to overcome a factor of 6 underestimate of hydroxyl (OH) concentrations observed during a warm (&nbsp;29 &deg;C) period. Modeled fluxes of acyl peroxy nitrates (APN) are quite sensitive to gradients in chemical production and loss, demonstrating that chemistry may perturb forest-atmosphere exchange even when the chemical timescale is long relative to the canopy mixing timescale. The model underestimates peroxy acetyl nitrate (PAN) fluxes by 50% and the exchange velocity by nearly a factor of three under warmer conditions, suggesting that near-surface APN sinks are underestimated relative to the sources. Nitric acid typically dominates gross dry N deposition at this site, though other reactive nitrogen (NOy) species can comprise up to 28% of the N deposition budget under cooler conditions. Upward NO2 fluxes cause the net above-canopy NOy flux to be &nbsp;30% lower than the gross depositional flux. CAFE under-predicts ozone fluxes and exchange velocities by &nbsp;20%. Large uncertainty in the parameterization of cuticular and ground deposition precludes conclusive attribution of non-stomatal fluxes to chemistry or surface uptake. Model-measurement comparisons of vertical concentration gradients for several emitted species suggests that the lower canopy airspace may be only weakly coupled with the upper canopy. Future efforts to model forest-atmosphere exchange will require a more mechanistic understanding of non-stomatal deposition and a more thorough characterization of in-canopy mixing processes.</p>
[1763] Kaser, L.., T.. Karl, B.. Yuan, R.. L. Mauldin, C.. A. Cantrell, A.. B. Guenther, E.. G. Patton, A.. J. Weinheimer, C.. Knote, J.. Orlando, et al., "Chemistry-turbulence interactions and mesoscale variability influence the cleansing efficiency of the atmosphere", Geophysical Research Letters, vol. 42, pp. 10894–10903, Dec, 2015.
Link: http://n2t.net/ark:/85065/d7gq709d
Abstract
<p>The hydroxyl radical (OH) is the most important oxidant in the atmosphere and the primary sink for isoprene, the dominant volatile organic compound emitted by vegetation. Recent research on the atmospheric oxidation capacity in isoprene-dominated environments has suggested missing radical sources leading to significant overestimation of the lifetime of isoprene. Here we report, for the first time, a comprehensive experimental budget of isoprene in the planetary boundary layer based on airborne flux measurements along with in situ OH observations in the Southeast and Central U.S. Our findings show that surface heterogeneity of isoprene emissions lead to a physical separation of isoprene and OH resulting in an effective slowdown in the chemistry. Depending on surface heterogeneity, the intensity of segregation (Is) could locally slow down isoprene chemistry up to 30%. The effect of segregated reactants in the planetary boundary layer on average has an influence on modeled OH radicals that is comparable to that of recently proposed radical recycling mechanisms.</p>
[Lee2005] Lee, A., GW. Schade, R. Holzinger, and AH. Goldstein, "A comparison of new measurements of total monoterpene flux with improved measurements of speciated monoterpene flux", Atmospheric Chemistry and Physics, vol. 5, no. 2: Copernicus GmbH, pp. 505–513, 2005.
Link: http://www.atmos-chem-phys.net/5/505/2005/acp-5-505-2005.pdf
[Davison2009] Davison, B., R. Taipale, B. Langford, P. Misztal, S. Fares, G. Matteucci, F. Loreto, JN. Cape, J. Rinne, and CN. Hewitt, "Concentrations and fluxes of biogenic volatile organic compounds above a Mediterranean macchia ecosystem in western Italy", Biogeosciences, vol. 6: EGU, pp. 1655–1670, 2009.
Link: http://nora.nerc.ac.uk/8091/
Abstract
Emission rates and concentrations of biogenic volatile organic compounds (BVOCs) were measured at a Mediterranean coastal site at Castelporziano, approximately 25 km south-west of Rome, between 7 May and 3 June 2007, as part of the ACCENT-VOCBAS field campaign on biosphere–atmosphere interactions. Concentrations and emission rates were measured using the disjunct eddy covariance (DEC) method utilizing three different proton transfer reaction mass spectrometers (PTR-MS) so allowing a comparison between the instruments. The high resolution data from the PTR-MS instruments considerably enhances the original BEMA measurements of the mid 1990s. Depending on the measurement period, the volume mixing ratios were in the range 1.6–3.5 ppbv for methanol, 0.44–1.3 ppbv for acetaldehyde, 0.96–2.1 ppbv for acetone, 0.10–0.14 ppbv for isoprene, and 0.13–0.30 ppbv for monoterpenes. A diurnal cycle in mixing ratios was apparent with daytime maxima for methanol, acetaldehyde, acetone, and isoprene. The fluxes ranged from 370–440 μg m−2 h−1 for methanol, 180–360 μg m−2 h−1 for acetaldehyde, 180–450 μg m−2 h−1 for acetone, 71–290 μg m−2 h−1 for isoprene, and 240–860 μg m−2 h−1 for monoterpenes. From the measured flux data (7 May–3 June) an average basal emission rate for the Macchia vegetation was calculated of 430 μg m−2 h−1 for isoprene and 1100 μg m−2 h−1 for monoterpenes.
[Davison2008] Davison, B.., A.. Brunner, C.. Ammann, C.. Spirig, M.. Jocher, and A.. Neftel, "Cut-induced VOC emissions from agricultural grasslands.", Plant Biol (Stuttg), vol. 10, no. 1: Department of Environmental Sciences, Lancaster University, Lancaster LA1 4YQ, UK. b.davison@lancaster.ac.uk, pp. 76–85, Jan, 2008.
Link: http://dx.doi.org/10.1055/s-2007-965043
Abstract
The introduction of proton transfer reaction mass spectrometry (PTR-MS) for fast response measurements of volatile organic compounds (VOC) has enabled the use of eddy covariance methods to investigate VOC fluxes on the ecosystem scale. In this study PTR-MS flux measurements of VOC were performed over agricultural grassland during and after a cut event. Selected masses detected by the PTR-MS showed fluxes of methanol, acetaldehyde, and acetone. They were highest directly after cutting and during the hay drying phase. Simultaneously, significant fluxes of protonated ion masses 73, 81, and 83 were observed. Due to the limited identification of compounds with the PTR-MS technique, GC-MS and GC-FID-PTR-MS techniques were additionally applied. In this way, ion mass 73 could be identified as 2-butanone, mass 81 mainly as (Z)-3-hexenal, and mass 83 mainly as the sum of (Z)-3-hexenol and hexenyl acetates. Hexenal, hexenols, and the hexenyl acetates are mostly related to plant wounding during cutting. It was found that legume plants and forbs emit a higher number of different VOC species than graminoids.
D
[1584] Hörtnagl, L., R. Clement, M. Graus, A. Hammerle, A. Hansel, and G. Wohlfahrt, "Dealing with disjunct concentration measurements in eddy covariance applications: a comparison of available approaches.", Atmos Environ (1994), vol. 44, May, 2010.
Link: http://www.sciencedirect.com/science/article/pii/S1352231010001810
Abstract
<p>Using proton transfer reaction mass spectrometry equipped with a quadrupol mass analyser to quantify the biosphere-atmosphere exchange of volatile organic compounds (VOC), concentrations of different VOC are measured sequentially. Depending on how many VOC species are targeted and their respective integration times, each VOC is measured at repeat rates on the order of a few seconds. This represents an order of magnitude longer sample interval compared to the standard eddy covariance (EC) method (5-20 Hz sampling rates). Here we simulate the effect of disjunct sampling on EC flux estimates by decreasing the time resolution of CO2 and H2O concentrations measured at 20 Hz above a temperate mountain grassland in the Austrian Alps. Fluxes for one month are calculated with the standard EC method and compared to fluxes calculated based on the disjunct data (1, 3 and 5 s sampling rates) using the following approaches: i) imputation of missing concentrations based on the nearest neighbouring samples (iDECnn), ii) imputation by linear interpolation (iDECli), and iii) virtual disjunct EC (vDEC), i.e. flux calculation based solely on the disjunct concentrations. It is shown that the two imputation methods result in additional low-pass filtering, longer lag times (as determined with the maximum cross-correlation method) and a flux loss of 3-30 % as compared to the standard EC method. A novel procedure, based on a transfer function approach, which specifically corrects for the effect of data treatment, was developed, resulting in improved correspondence (to within 2 %). The vDEC method yields fluxes which approximate the true (20 Hz) fluxes to within 3-7 % and it is this approach we recommend because it involves no additional empirical corrections. The only drawback of the vDEC method is the noisy nature of the cross-correlations, which poses problems with lag determination - practical approaches to overcome this limitation are discussed.</p>
[Bamberger2011] Bamberger, I., L. Hörtnagl, TM. Ruuskanen, R. Schnitzhofer, M. Müller, M. Graus, T. Karl, G. Wohlfahrt, and A. Hansel, "Deposition fluxes of terpenes over grassland", Journal of Geophysical Research: Atmospheres (1984–2012), vol. 116, no. D14: Wiley Online Library, 2011.
Link: http://onlinelibrary.wiley.com/doi/10.1029/2010JD015457/full
Abstract
Eddy covariance flux measurements were carried out for two subsequent vegetation periods above a temperate mountain grassland in an alpine valley using a proton-transfer-reaction-mass spectrometer (PTR-MS) and a PTR time-of-flight-mass spectrometer (PTR-TOF). In 2008 and during the first half of the vegetation period 2009 the volume mixing ratios (VMRs) for the sum of monoterpenes (MTs) were typically well below 1 ppbv and neither MT emission nor deposition was observed. After a hailstorm in July 2009 an order of magnitude higher amount of terpenes was transported to the site from nearby coniferous forests causing elevated VMRs. As a consequence, deposition fluxes of terpenes to the grassland, which continued over a time period of several weeks without significant reemission, were observed. For days without precipitation the deposition occurred at velocities close to the aerodynamic limit. In addition to monoterpene uptake, deposition fluxes of the sum of sesquiterpenes (SQTs) and the sum of oxygenated terpenes (OTs) were detected. Considering an entire growing season for the grassland (i.e., 1 April to 1 November 2009), the cumulative carbon deposition of monoterpenes reached 276 mg C m−2. This is comparable to the net carbon emission of methanol (329 mg C m−2), which is the dominant nonmethane volatile organic compound (VOC) emitted from this site, during the same time period. It is suggested that deposition of monoterpenes to terrestrial ecosystems could play a more significant role in the reactive carbon budget than previously assumed.
[Bamberger2012] Bamberger, I., L. Hoertnagl, T. Ruuskanen, R. Schnitzhofer, M. Müller, M. Graus, T. Karl, G. Wohlfahrt, and A. Hansel, "Deposition of terpenes to vegetation-a paradigm shift towards bidirectional VOC exchange?", EGU General Assembly Conference Abstracts, vol. 14, pp. 7949, 2012.
Link: http://adsabs.harvard.edu/abs/2012EGUGA..14.7949B
Abstract
Biogenic volatile organic compounds (BVOCs) are important precursors for secondary organic aerosol (SOA) formation (Hallquist et al., 2009). In addition reactive BVOCs play a crucial role in local tropospheric ozone production (Atkinson, 2000). According to the present scientific understanding vegetation is recognized as a major VOC emission source rather than a deposition sink. Our recent observations however demonstrate that an uptake of terpene compounds to mountain grassland can be significant - at least under certain atmospheric conditions. After a severe hailstorm volume mixing ratios (VMR) of locally emitted terpene compounds originating from conifers located at the mountain slopes were strongly enhanced, even during daytime hours. Weeks after the hailstorm our PTR-MS and PTR-time-of-flight (PTR-TOF) instruments still measured deposition fluxes of monoterpenes (m/z 137.133), sesquiterpenes (m/z 205.195), and oxygenated terpenes (m/z 153.128) to the grassland. The total amount of terpenoids (on a carbon basis) deposited to the grassland during the weeks after the hailstorm is comparable to the total methanol emission of the entire growing season (Bamberger et al., 2011). These findings pose the question whether the terminology should be adjusted from VOC emission to VOC exchange.

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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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