An improved, automated whole air sampler and gas chromatography mass spectrometry analysis system for volatile organic compounds in the atmosphere

Atmospheric measurement techniques, Journal Year: 2017, Volume and Issue: 10(1), P. 291 - 313

Published: Jan. 26, 2017

Abstract. Volatile organic compounds were quantified during two aircraft-based field campaigns using highly automated, whole air samplers with expedited post-flight analysis via a new custom-built, field-deployable gas chromatography–mass spectrometry instrument. During flight, samples pressurized stainless steel bellows compressor into electropolished canisters. The analyzed novel chromatograph system designed specifically for use which eliminates the need liquid nitrogen. Instead, Stirling cooler is used cryogenic sample pre-concentration at temperatures as low −165 °C. was fully automated on 20 min cycle to allow unattended processing of an entire flight 72 canisters within 30 h, thereby reducing typical residence times in less than 3 days. analytical capable quantifying wide suite C2 C10 part-per-trillion sensitivity. This paper describes sampling and systems, along data procedures include peak-fitting software package rapid chromatographic reduction. Instrument sensitivities, uncertainties artifacts are presented 35 trace species canister samples. Comparisons reported mixing ratios from each campaign measurements other instruments also presented.

Language: Английский

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BVOC–aerosol–climate feedbacks investigated using NorESM

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(7), P. 4763 - 4782

Published: April 9, 2019

Abstract. Both higher temperatures and increased CO2 concentrations are (separately) expected to increase the emissions of biogenic volatile organic compounds (BVOCs). This has been proposed initiate negative climate feedback mechanisms through formation secondary aerosol (SOA). More SOA can make clouds more reflective, which provide a cooling. Furthermore, in also lead scattering, resulting an diffuse radiation. could boost gross primary production (GPP) further BVOC emissions. In this study, we have used Norwegian Earth System Model (NorESM) investigate both these mechanisms. Three sets experiments were set up quantify with respect (1) doubling CO2, (2) increasing corresponding (3) combined effect warmer climate. For each experiments, ran two simulations, identical setups, except for One simulation was run interactive emissions, allowing respond changes and/or other simulation, fixed at present-day conditions, essentially turning off. The comparison simulations enables us step along as well estimate their overall relevance future We find that significant impact on annual global 63 % when is turned compared off, largest response changed. levels mass (max 53 %) result particles new particle larger condensation. cloud properties −0.43 W m−2 stronger net forcing. becomes about 50 model reduced anthropogenic indicating will become even important decrease precursor do not GPP due scattering scale. Instead, fate seems be controlled by effects clouds. However, associated found contribute potentially enhanced direct forcing (−0.06 m−2). total −0.49 m−2, it potential offset 13 CO2.

Language: Английский

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Postsynthetic N-methylation making a metal–organic framework responsive to alkylamines

Chemical Communications, Journal Year: 2017, Volume and Issue: 53(10), P. 1747 - 1750

Published: Jan. 1, 2017

The postsynthetically created electron-deficient bipyridinium moieties in a Zr-MOF provide charge-transfer sites for selectively recognizing and capturing alkylamines with fast reversible vapochromism luminescence quenching.

Language: Английский

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Composition and volatility of secondary organic aerosol (SOA) formed from oxidation of real tree emissions compared to simplified volatile organic compound (VOC) systems

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(9), P. 5629 - 5644

Published: May 13, 2020

Abstract. Secondary organic aerosol (SOA) is an important constituent of the atmosphere where SOA particles are formed chiefly by condensation or reactive uptake oxidation products volatile compounds (VOCs). The mass yield in particle formation, as well chemical composition and volatility particles, determined identity VOC precursor(s) conditions they experience. In this study, we used flow reactor to generate biogenic from Scots pine emissions. Mass yields, were characterized compared with α-pinene a mixture acyclic–monocyclic sesquiterpenes (farnesenes bisabolenes), which significant components yields for emissions dominated farnesenes lower than but higher artificial bisabolenes. reduction farnesene- bisabolene-dominated mixtures due exocyclic C=C bond scission these during ozonolysis leading smaller generally more products. had similar either single precursor simple VOCs. Applying physical stress plants increased their monoterpene, especially monocyclic β-phellandrene, emissions, further decreased yield. Our results highlight need account complexity structure real-world stress-induced changes plant when modelling production properties atmosphere. These emphasize that increase decrease relative monoterpene sesquiterpene should not be indicator volatility.

Language: Английский

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Isoprene-Derived Organosulfates: Vibrational Mode Analysis by Raman Spectroscopy, Acidity-Dependent Spectral Modes, and Observation in Individual Atmospheric Particles

The Journal of Physical Chemistry A, Journal Year: 2017, Volume and Issue: 122(1), P. 303 - 315

Published: Dec. 8, 2017

Isoprene, the most abundant biogenic volatile organic compound (BVOC) in atmosphere, and its low-volatility oxidation products lead to secondary aerosol (SOA) formation. Isoprene-derived organosulfates formed from reactions of isoprene with sulfate particle phase are a significant component SOA can hydrolyze forming polyols. Despite characterization by mass spectrometry, their basic structural spectroscopic properties remain poorly understood. Herein, Raman microspectroscopy density functional theory (DFT) calculations (CAM-B3LYP level theory) were combined analyze vibrational modes key organosulfates, 3-methyltetrol esters (racemic mixture two isomers), racemic 2-methylglyceric acid ester, hydrolysis products, 2-methyltetrols, acid. Two intense identified, ν(RO–SO3) (846 ± 4 cm–1) νs(SO3) (1065 2 cm–1), along lower intensity δ(SO3) mode (586 cm–1). For esters, deprotonation carboxylic at pH values above pKa decreased carbonyl stretch frequency (1724 while carboxylate grew for νs(COO–) νa(COO–) 1413 1594 cm–1, respectively. The observed individual atmospheric particles be used future studies complex mixtures distinguish inorganic or products.

Language: Английский

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Airborne particulate matter pollution in urban China: a chemical mixture perspective from sources to impacts

National Science Review, Journal Year: 2016, Volume and Issue: 4(4), P. 593 - 610

Published: Nov. 8, 2016

Abstract Rapid urban and industrial development has resulted in severe air-pollution problems developing countries such as China, especially highly industrialized populous clusters. Dissecting the complex mixtures of airborne particulate matter (PM) been a key scientific focus last two decades, leading to significant advances understanding physicochemical compositions for comprehensive source apportionment. However, identifying causative components with an attributable link population-based health outcomes remains huge challenge. The microbiome, integral dimension PM mixture, is unexplored frontier terms identities functions atmospheric processes human health. In this review, we identify major gaps addressing these issues, recommend holistic framework evaluating sources, impacts pollution. Such approach knowledge generated will facilitate formulation regulatory measures control pollution China elsewhere.

Language: Английский

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Characterization of organic nitrate constituents of secondary organic aerosol (SOA) from nitrate-radical-initiated oxidation of limonene using high-resolution chemical ionization mass spectrometry

Atmospheric chemistry and physics, Journal Year: 2018, Volume and Issue: 18(8), P. 5467 - 5481

Published: April 20, 2018

Abstract. The gas-phase nitrate radical (NO3⚫) initiated oxidation of limonene can produce organic species with varying physical properties. Low-volatility products contribute to secondary aerosol (SOA) formation and nitrates may serve as a NOx reservoir, which could be especially important in regions high biogenic emissions. This work presents the measurement results from flow reactor studies on reaction NO3⚫ using High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) combined Filter Inlet for Gases AEROsols (FIGAERO). Major condensed-phase were compared those Master Mechanism (MCM) mechanism, many non-listed identified. volatility properties most prevalent produced SOA determined. Analysis multiple experiments resulted identification several dominant (including C10H15NO6, C10H17NO6, C8H11NO6, C10H17NO7, C9H13NO7) that occurred under all conditions considered. Additionally, dimers was consistently observed these resided almost completely particle phase. identities are discussed, mechanisms proposed. Cluster analysis desorption temperatures corresponding analyzed particle-phase yielded at least five distinct groupings based combination molecular weight profile. Overall, indicate by produces complex mixture highly oxygenated monomer dimer formation.

Language: Английский

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A method for extracting calibrated volatility information from the FIGAERO-HR-ToF-CIMS and its experimental application

Atmospheric measurement techniques, Journal Year: 2019, Volume and Issue: 12(3), P. 1429 - 1439

Published: March 5, 2019

Abstract. The Filter Inlet for Gases and AEROsols (FIGAERO) is an inlet specifically designed to be coupled with the Aerodyne High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS). FIGAERO-HR-ToF-CIMS provides simultaneous molecular information relating both gas- particle-phase samples has been used extract vapour pressures (VPs) of compounds desorbing from filter whilst giving quantitative concentrations in particle phase. However, such extraction measured components requires use appropriate, well-defined, reference compounds. Vapour homologous series polyethylene glycols (PEG) ((H-(O-CH2-CH2)n-OH) n=3 n=8), covering a range (VP) (10−1 10−7 Pa) that are atmospherically relevant, have shown reproduced well by different techniques, including Knudsen Effusion Spectrometry (KEMS). This first which number pressure measurement techniques found agreement, indicating utility as calibration standard, providing ideal set benchmark accurate characterization FIGAERO extracting chambers real atmosphere. To demonstrate this, single-component mixture measurements made using two instruments based on new determined PEG series. VP values extracted agree those KEMS reported literature, validating this approach data FIGAERO. method then applied chamber measurements, known products estimated.

Language: Английский

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Carboxylic acids from limonene oxidation by ozone and hydroxyl radicals: insights into mechanisms derived using a FIGAERO-CIMS

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(20), P. 13037 - 13052

Published: Oct. 22, 2019

Abstract. This work presents the results from a flow reactor study on formation of carboxylic acids limonene oxidation in presence ozone under NOx-free conditions dark. A High-Resolution Time-of-Flight acetate Chemical Ionisation Mass Spectrometer (HR-ToF-CIMS) was used combination with Filter Inlet for Gases and AEROsols (FIGAERO) to measure gas particle phases. The revealed that produced large amounts which are important contributors secondary organic aerosol (SOA) formation. highest 10 contributed 56 %–91 % total gas-phase signal, dominant species most experiments were C8H12O4, C9H14O4, C7H10O4 C10H16O3. particle-phase composition generally more complex than composition, 47 %–92 signal. phase C8H12O5, C9H14O5, C9H12O5 C10H16O4. measured concentration dimers bearing at least one acid function very low, indicating acidic play minor role SOA via (O3)/hydroxyl (OH) limonene. Based various experimental conditions, compositions all modelled using descriptions Master Mechanism (MCM). experiment model provided yield (C7–C10) order (2 %–23 %–15 %, respectively). Significant concentrations 11 acids, 16 included MCM CIMS. However, predictions were, some cases, inconsistent measurement results, especially regarding OH dependence. Reaction mechanisms suggested fill-in knowledge gaps. Using additional proposed this work, nearly 75 observed signal our lowest (8.4 ppb converted, ca. 23 yield) carried out humid can be understood.

Language: Английский

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A review of secondary organic aerosols formation focusing on organosulfates and organic nitrates

Journal of Hazardous Materials, Journal Year: 2022, Volume and Issue: 430, P. 128406 - 128406

Published: Feb. 2, 2022

Language: Английский

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