scholarly journals Flux measurements of volatile organic compounds from an urban landscape

2005 ◽  
Vol 32 (20) ◽  
Author(s):  
E. Velasco
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Urban Landscape ◽  
Volatile Organic ◽  
Flux Measurements

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 Technical note: Interferences of volatile organic compounds (VOCs) on methane concentration measurements

2019 ◽  
Vol 16 (17) ◽  
pp. 3319-3332 ◽  
Author(s):  
Lukas Kohl ◽  
Markku Koskinen ◽  
Kaisa Rissanen ◽  
Iikka Haikarainen ◽  
Tatu Polvinen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Absorption Spectroscopy ◽  
Proton Transfer Reaction ◽  
Technical Note ◽  
Mixing Ratio ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Volatile Organic ◽  
Flux Measurements

Abstract. Studies that quantify plant methane (CH4) emission rely on the accurate measurement of small changes in the mixing ratio of CH4 that coincide with much larger changes in the mixing ratio of volatile organic compounds (VOCs). Here, we assessed whether 11 commonly occurring VOCs (e.g. methanol, α- and β-pinene, Δ3-carene) interfered with the quantitation of CH4 by five laser-absorption spectroscopy and Fourier-transformed infrared spectroscopy (FTIR) based CH4 analysers, and quantified the interference of seven compounds on three instruments. Our results showed minimal interference with laser-based analysers and underlined the importance of identifying and compensating for interferences with FTIR instruments. When VOCs were not included in the spectral library, they exerted a strong bias on FTIR-based instruments (64–1800 ppbv apparent CH4 ppmv−1 VOC). Minor (0.7–126 ppbv ppmv−1) interference with FTIR-based measurements were also detected when the spectrum of the interfering VOC was included in the library. In contrast, we detected only minor (<20 ppbv ppmv−1) and transient (< 1 min) VOC interferences on laser-absorption spectroscopy-based analysers. Overall, our results demonstrate that VOC interferences have only minor effects on CH4 flux measurements in soil chambers, but may severely impact stem and shoot flux measurements. Laser-absorption-based instruments are better suited for quantifying CH4 fluxes from plant leaves and stems than FTIR-based instruments; however, significant interferences in shoot chamber measurements could not be excluded for any of the tested instruments. Our results furthermore showed that FTIR can precisely quantify VOC mixing ratios and could therefore provide a method complementary to proton-transfer-reaction mass spectrometry (PTR-MS).

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 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 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.

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