scholarly journals First eddy covariance flux measurements of semi-volatile organic compounds with the PTR3-TOF-MS

2021 ◽  
Vol 14 (12) ◽  
pp. 8019-8039
Author(s):  
Lukas Fischer ◽  
Martin Breitenlechner ◽  
Eva Canaval ◽  
Wiebke Scholz ◽  
Marcus Striednig ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Oxidation Products ◽  
Concentration Data ◽  
Single Digit ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Flight Reaction ◽  
Tof Ms

Abstract. We present first eddy covariance flux measurements with the PTR3-TOF-MS, a novel proton transfer time of flight reaction mass spectrometer. During 3 weeks in spring 2016, the instrument recorded 10 Hz data of biogenic volatile organic compounds above a boreal forest, on top of a measurement tower at the SMEAR (Station for Measuring Ecosystem –Atmosphere Relations) II station in Hyytiälä, Finland. Flux and concentration data of isoprene, monoterpenes, and sesquiterpenes were compared to the literature. Due to the improved instrument sensitivity and a customized wall-less inlet design, we could detect fluxes of semi-volatile and low-volatility organic compounds with less than single-digit picomol per square meter per second (pmolm-2s-1) values for the first time. These compounds include sesquiterpene oxidation products and diterpenes. Daytime diterpene fluxes were in the range of 0.05 to 0.15 pmolm-2s-1, which amounts to about 0.25 % to 0.5 % of the daytime sesquiterpene flux above canopy.

scholarly journals First Eddy Covariance Flux Measurements of Semi Volatile Organic Compounds with the PTR3-TOF-MS

2021 ◽  
Author(s):  
Lukas Fischer ◽  
Martin Breitenlechner ◽  
Eva Canaval ◽  
Wiebke Scholz ◽  
Marcus Striednig ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Proton Transfer Reaction ◽  
Oxidation Products ◽  
Concentration Data ◽  
Single Digit ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Tof Ms

Abstract. We present first eddy covariance flux measurements with the PTR3-TOF-MS, a novel proton-transfer-reaction mass-spectrometer (PTR-MS). During three weeks in spring 2016 the instrument recorded 10 Hz BVOC data on top of the SMEAR II tower in Hyytiälä, Finland. Flux and concentration data of isoprene, monoterpenes and sesquiterpenes were compared to the literature. Due to the improved instrument sensitivity and a customized “wall less” inlet design we could detect a number of fluxes of semi-volatile and low volatile organic compounds (SVOC and LVOC) with less than single digit picomol/m2/s values for the first time. These compounds include sesquiterpene oxidation products and diterpenes. Daytime diterpene fluxes were in the range of 0.05 to 0.15 picomol/m2/s, which amounts to about 0.25 % to 0.5 % of the daytime sesquiterpene flux above canopy.

scholarly journals Contributions to OH reactivity from unexplored volatile organic compounds measured by PTR-ToF-MS – A case study in a suburban forest of the Seoul Metropolitan Area during KORUS-AQ 2016

2020 ◽  
Author(s):  
Dianne Sanchez ◽  
Roger Seco ◽  
Dasa Gu ◽  
Alex Guenther ◽  
John Mak ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Metropolitan Area ◽  
Forest Canopy ◽  
Oxidation Products ◽  
Ionization Mass ◽  
Seoul Metropolitan Area ◽  
Volatile Organic ◽  
Tof Ms

Abstract. We report OH reactivity observations by a chemical ionization mass spectrometer – comparative reactivity method (CIMS-CRM) instrument in a suburban forest of the Seoul Metropolitan Area (SMA) during Korea US Air Quality Study (KORUS-AQ 2016) from mid-May to mid-June of 2016. A comprehensive observational suite was deployed to quantify reactive trace gases inside of the forest canopy including a high-resolution proton transfer reaction time of flight mass spectrometer (PTR-ToF-MS). An average OH reactivity of 30.7 ± 5.1 s−1 was observed, while the OH reactivity calculated from CO, NO + NO2 (NOx), ozone (O3), sulfur dioxide (SO2), and 14 volatile organic compounds (VOCs) was 11.8 ± 1.0 s−1. An analysis of 346 peaks from the PTR-ToF-MS accounted for an additional 6.0 ± 2.2 s−1 of the total measured OH reactivity, leaving 42.0 % missing OH reactivity. The missing OH reactivity most likely comes from VOC oxidation products of both biogenic and anthropogenic origin.

scholarly journals Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

2008 ◽  
Vol 8 (4) ◽  
pp. 14273-14309 ◽  
Author(s):  
T. Karl ◽  
E. Apel ◽  
A. Hodzic ◽  
D. Riemer ◽  
D. Blake ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Mexico City ◽  
Biomass Burning ◽  
Minor Role ◽  
Industrial Emissions ◽  
Tertiary Butyl ◽  
Volatile Organic ◽  
Flux Measurements

Abstract. Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-average midday toluene and benzene fluxes are calculated to be on the order of 15.5±4.0 mg/m2/h and 4.7±2.3 mg/m2/h respectively. These values argue for an underestimation of toluene and benzene emissions in current inventories used for the Mexico City Metropolitan Area (MCMA). Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10–15) including the International airport (e.g. 3–5) and a mean flux (concentration) ratio of 3.2±0.5 (3.9±0.3) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (Benzene/Toluene/Ethylbenzene/m,p,o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH3CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >90% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds (0–10%) in the MCMA.

scholarly journals Cryptogamic organisms are a substantial source and sink for volatile organic compounds in the Amazon region

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Achim Edtbauer ◽  
Eva Y. Pfannerstill ◽  
Ana Paula Pires Florentino ◽  
Cybelli G. G. Barbosa ◽  
Emilio Rodriguez-Caballero ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Forest Canopy ◽  
Oxidation Products ◽  
Atmospheric Oxidation ◽  
Tropical Rainforests ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Made In

AbstractCryptogamic organisms such as bryophytes and lichens cover most surfaces within tropical forests, yet their impact on the emission of biogenic volatile organic compounds is unknown. These compounds can strongly influence atmospheric oxidant levels as well as secondary organic aerosol concentrations, and forest canopy leaves have been considered the dominant source of these emissions. Here we present cuvette flux measurements, made in the Amazon rainforest between 2016–2018, and show that common bryophytes emit large quantities of highly reactive sesquiterpenoids and that widespread lichens strongly uptake atmospheric oxidation products. A spatial upscaling approach revealed that cryptogamic organisms emit sesquiterpenoids in quantities comparable to current canopy attributed estimates, and take up atmospheric oxidation products at rates comparable to hydroxyl radical chemistry. We conclude that cryptogamic organisms play an important and hitherto overlooked role in atmospheric chemistry above and within tropical rainforests.

scholarly journals Boreal forest soil is a significant and diverse source of volatile organic compounds

2018 ◽  
Author(s):  
Mari Mäki ◽  
Hermanni Aaltonen ◽  
Jussi Heinonsalo ◽  
Heidi Hellén ◽  
Jukka Pumpanen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Forest Soil ◽  
Organic Compounds ◽  
Coniferous Forest ◽  
Soil Surface ◽  
Surface Flux ◽  
Gas Diffusion ◽  
Oxidation Products ◽  
Volatile Organic ◽  
Flux Measurements

Abstract. Vegetation emissions of volatile organic compounds (VOCs) are intensively studied world-wide because oxidation products of VOCs contribute to atmospheric processes, but the quantities by which different species of VOCs are produced by soil, or how effectively belowground VOCs are released into the atmosphere from soil remains largely unknown. This is the first published study that measures belowground VOC concentrations at different depths in a podzol combined with simultaneous soil surface flux measurements in a boreal coniferous forest. More than 50 VOCs, dominated by monoterpenes and sesquiterpenes, were detected in the air space in the soil during the two measurement campaigns. Organic forest soil was a significant monoterpene source as it contained fresh isoprenoid-rich litter, and the concentrations of monoterpenes were comparable to the VOC concentrations in the air above the coniferous forest. Belowground monoterpene concentrations were largely decoupled from forest floor monoterpene fluxes; thus, it seems that production processes and storages of VOCs partly differ from those VOCs that are simultaneously emitted from the soil surface. Relatively high isoprenoid concentrations were measured under snow cover, which indicates that snow and ice cover hinders gas diffusion and causes belowground accumulation of VOCs when the activity of vegetation is very low.

scholarly journals Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

2009 ◽  
Vol 9 (1) ◽  
pp. 271-285 ◽  
Author(s):  
T. Karl ◽  
E. Apel ◽  
A. Hodzic ◽  
D. D. Riemer ◽  
D. R. Blake ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Minor Role ◽  
Industrial Emissions ◽  
Butyl Ether ◽  
Tertiary Butyl ◽  
Volatile Organic ◽  
Flux Measurements

Abstract. Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-median midday toluene and benzene fluxes are calculated to be on the order of 14.1±4.0 mg/m2/h and 4.7±2.3 mg/m2/h, respectively. For comparison the adjusted CAM2004 emission inventory estimates toluene fluxes of 10 mg/m2/h along the footprint of the flight-track. Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10–15 g/g) including the International airport (e.g. 3–5 g/g) and a mean flux (concentration) ratio of 3.2±0.5 g/g (3.9±0.3 g/g) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (BTEX– Benzene/Toluene/Ethylbenzene/m, p, o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH3CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >87% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds in the MCMA (2–13%).

Airborne Flux Measurements of BVOCs above Californian Oak Forests: Experimental Investigation of Surface and Entrainment Fluxes, OH Densities, and Damköhler Numbers

2013 ◽  
Vol 70 (10) ◽  
pp. 3277-3287 ◽  
Author(s):  
T. Karl ◽  
P. K. Misztal ◽  
H. H. Jonsson ◽  
S. Shertz ◽  
A. H. Goldstein ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Time Scale ◽  
Reactive Species ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Airborne Flux Measurements ◽  
Entrainment Fluxes

Abstract 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., 1–5 s) can still be used to determine eddy covariance fluxes in the mixed layer above land, where typical length scales of 0.5–3 km were observed. Flux divergence of isoprene measured in the planetary boundary layer (PBL) is indicative of OH densities in the range of 4–7 × 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 0.3–0.9. Most of the isoprene is oxidized in the PBL with entrainment fluxes of about 10% compared to the corresponding surface fluxes. Entrainment velocities of 1–10 cm s−1 were measured. The authors present implications for parameterizing PBL schemes of reactive species in regional and global models.

scholarly journals Measurements of volatile organic compounds over West Africa

2010 ◽  
Vol 10 (2) ◽  
pp. 3861-3892 ◽  
Author(s):  
J. G. Murphy ◽  
D. E. Oram ◽  
C. E. Reeves
Keyword(s):  
Boundary Layer ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Marine Boundary Layer ◽  
Deep Convection ◽  
Proton Transfer Reaction ◽  
Oxidation Products ◽  
High Time Resolution ◽  
Airborne Measurements ◽  
Volatile Organic

Abstract. In this paper we describe measurements of volatile organic compounds (VOCs) made using a Proton Transfer Reaction Mass Spectrometer (PTR-MS) aboard the UK Facility for Atmospheric Airborne Measurements during the African Monsoon Multidisciplinary Analyses (AMMA) campaign. Observations were made during approximately 85 h of flying time between 17 July and 17 August 2006, above an area between 4° N and 18° N and 3° W and 4° E, encompassing ocean, mosaic forest, and the Sahel desert. High time resolution observations of counts at mass to charge (m/z) ratios of 42, 59, 69, 71, and 79 were used to calculate mixing ratios of acetonitrile, acetone, isoprene, the sum of methyl vinyl ketone and methacrolein, and benzene, respectively using laboratory-derived humidity-dependent calibration factors. Strong spatial associations between vegetation and isoprene and its oxidation products were observed in the boundary layer, consistent with biogenic emissions followed by rapid atmospheric oxidation. Acetonitrile, benzene, and acetone were all enhanced in airmasses which had been heavily influenced by biomass burning. Benzene and acetone were also elevated in airmasses with urban influence from cities such as Lagos, Cotonou, and Niamey. The observations provide evidence that both deep convection and mixing associated with fair-weather cumulus were responsible for vertical redistribution of VOCs emitted from the surface. Profiles over the ocean showed a depletion of acetone in the marine boundary layer, but no significant decrease for acetonitrile.

scholarly journals Eddy covariance emission and deposition flux measurements using proton transfer reaction-time of flight-mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes

2012 ◽  
Vol 12 (8) ◽  
pp. 20435-20482 ◽  
Author(s):  
J.-H. Park ◽  
A. H. Goldstein ◽  
J. Timkovsky ◽  
S. Fares ◽  
R. Weber ◽  
...  
Keyword(s):  
Reaction Time ◽  
Proton Transfer ◽  
Organic Compounds ◽  
Transfer Reaction ◽  
Vertical Gradient ◽  
Proton Transfer Reaction ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Ion Species ◽  
Tof Ms

Abstract. During summer 2010, a proton transfer reaction-time of flight-mass spectrometer (PTR-TOF-MS) and a standard proton transfer reaction mass spectrometer (PTR-MS) were deployed simultaneously for one month in an orange orchard in the Central Valley of California to collect continuous data suitable for eddy covariance (EC) flux calculations. The high time resolution (5 Hz) and high mass resolution (up to 5000 m Δ m−1) data from the PTR-TOF-MS provided the basis for calculating the concentration and flux for a wide range of volatile organic compounds (VOC). Throughout the campaign, 664 mass peaks were detected in mass-to-charge ratios between 10 and 1278. Here we present PTR-TOF-MS EC fluxes of the 27 ion species for which the vertical gradient was simultaneously measured by PTR-MS. These EC flux data were validated through spectral analysis (i.e. co-spectrum, normalized co-spectrum, and ogive). Based on inter-comparison of the two PTR instruments, no significant instrumental biases were found in either mixing ratios or fluxes, and the data showed agreement within 5% on average for methanol and acetone. For the measured biogenic volatile organic compounds (BVOC), the EC fluxes from PTR-TOF-MS were in agreement with the qualitatively inferred flux directions from vertical gradient measurements by PTR-MS. For the 27 selected ion species reported here, the PTR-TOF-MS measured total (24 h) mean net flux of 299 μg C m−2 h−1. The dominant BVOC emissions from this site were monoterpenes (m/z 81.070 + m/z 137.131 + m/z 95.086, 34%, 102 μg C m−2 h−1) and methanol (m/z 33.032, 18%, 72 μg C m−2 h−1). The next largest fluxes were detected at the following masses (attribution in parenthesis): m/z 59.048 (mostly acetone, 12.2%, 36.5 μg C m−2 h−1), m/z 61.027 (mostly acetic acid, 11.9%, 35.7 μg C m−2 h−1), m/z 93.069 (para-cymene + toluene, 4.1%, 12.2 μg C m−2 h−1), m/z 45.033 (acetaldehyde, 3.8%, 11.5 μg C m−2 h−1), m/z 71.048 (methylvinylketone + methacrolein, 2.4%, 7.1 μg C m−2 h−1), and m/z 69.071 (isoprene + 2-methyl-3-butene-2-ol, 1.8%, 5.3 μg C m−2 h−1). Low levels of emission and/or deposition (<1.6% for each, 5.8% in total flux) were observed for the additional reported masses. Overall, our results show that EC flux measurements using PTR-TOF-MS is a powerful new tool for characterizing the biosphere-atmosphere exchange including both emission and deposition for a large range of BVOC and their oxidation products.

Eddy covariance (EC) fluxes of monoterpene oxidation products from a boreal forest canopy

2020 ◽  
Author(s):  
Lejish Vettikkat ◽  
Arttu Ylisirniö ◽  
Iida Pullinen ◽  
Luís Miguel Feijó Barreira ◽  
Pasi Miettinen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Time Of Flight ◽  
Ground Level ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Aerosol Formation ◽  
Flux Measurements

&lt;p&gt;Oxidation of volatile organic compounds (VOC) by ozone (O&lt;sub&gt;3&lt;/sub&gt;), hydroxyl radicals (OH) and nitrogen oxide radicals (NO&lt;sub&gt;3&lt;/sub&gt;, NOx) reduces their volatility and leads to the formation of secondary organic aerosols (SOA) through gas-particle partitioning. Recent studies have shown that monoterpene (C&lt;sub&gt;10&lt;/sub&gt;H&lt;sub&gt;16&lt;/sub&gt;) oxidation products can participate in all stages of aerosol formation, especially in forested boreal environments. However, deposition of these semi-volatile and (extremely) low-volatility organic compounds (SVOC, LVOC, ELVOC) to surfaces in the canopy directly competes with the gas-particle partitioning and has a substantial effect (~50%) on organic aerosol loading. Hence understanding the fate of these oxidation products is crucial in determining the organic aerosol budget and thereby constraining their contribution to climate-relevant processes such as new-particle formation and cloud formation.&lt;/p&gt;&lt;p&gt;Oxidation products of monoterpenes were measured at the station for measuring ecosystem atmosphere relations (SMEAR II), a boreal forest research station in Hyyti&amp;#228;l&amp;#228;, Finland, in spring/summer 2019. The forest is dominated by Scots pine (&lt;em&gt;Pinus sylvestris&lt;/em&gt; L.) and Norway spruce (&lt;em&gt;Picea abies&lt;/em&gt; (L.) H. Karst) which are well known high monoterpene emitters. Eddy covariance (EC) flux measurements of oxygenated organic compounds in the gas phase were performed using an iodide-adduct high-resolution time-of-flight chemical ionization mass spectrometer (I-CIMS) with high frequency (5 Hz) co-located with a sonic anemometer (METEK USA-1) on a tower, 35 m above the forest floor. The ion-molecule reaction (IMR) chamber of I-CIMS was actively humidified to mitigate the dependence of the sensitivity of the measurements on the ambient relative humidity. The EC data were analysed following standard correction procedures like lag correction, coordinate rotation and uncertainty analysis. VOCs and oxygenated VOCs were also measured at ground level using a Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus PTR-MS), which is sensitive also to the majority of compounds measured by I-CIMS.&lt;/p&gt;&lt;p&gt;We present the first continuous I-CIMS dataset at high time resolution (5 Hz) from a tall tower and calculate the Eddy covariance fluxes of a wide range of monoterpene oxidation products during the primary plant-growth season in a boreal forest. Bidirectional fluxes for formic acid (HCOOH) were observed at a higher temporal resolution than reported in earlier studies. We found an increasing trend in the deposition velocity for heavier monoterpene oxidation products which enables us to constrain the net flow of organics between the atmosphere and the canopy layer using the continuity/mass balance equation. When coupled to ground-based measurements using Vocus-PTR, our EC flux measurements will give further insight about the abundance of organics above the canopy vs near ground-level. We also plan to integrate our observations with a chemical transport model containing details of monoterpene oxidation chemistry (ADCHEM) to simulate the sources and sinks and to derive parameterizations for representing the dry deposition rates of monoterpene oxidation products in the boreal forested environments.&lt;/p&gt;

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