Chemical characterization of oxygenated organic compounds in the gas phase and particle phase using iodide CIMS with FIGAERO in urban air

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(11), P. 8455 - 8478

Published: June 3, 2021

Abstract. The atmospheric processes under polluted environments involving interactions of anthropogenic pollutants and natural emissions lead to the formation various complex secondary products. Therefore, characterization oxygenated organic compounds in urban areas remains a pivotal issue our understanding evolution carbon. Here, we describe measurements an iodide chemical ionization time-of-flight mass spectrometer installed with Filter Inlet for Gases AEROsols (FIGAERO-I-CIMS) both gas phase particle at site Guangzhou, typical megacity southern China, during autumn 2018. Abundant containing two five oxygen atoms were observed, including acids, multi-functional typically emitted from biomass burning, oxidation products biogenic hydrocarbons aromatics. Photochemistry played dominant roles gaseous acids isoprene-derived nitrates, while nighttime chemistry contributed significantly monoterpene-derived nitrates inorganics. Nitrogen-containing occupied significant fraction total signal phases, elevated fractions higher molecular weights. Measurements by FIGAERO-I-CIMS explained 24 ± 0.8 % aerosol measured (AMS), increased more aged aerosol. systematical interpretation spectra area Guangzhou provides holistic view numerous atmosphere, which can serve as reference future field regions.

Language: Английский

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Evaluating Organic Aerosol Sources and Evolution with a Combined Molecular Composition and Volatility Framework Using the Filter Inlet for Gases and Aerosols (FIGAERO)

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(8), P. 1415 - 1426

Published: July 10, 2020

ConspectusThe complex array of sources and transformations organic carbonaceous material that comprises an important fraction atmospheric fine particle mass, known as aerosol, has presented a long running challenge for accurate predictions its abundance, distribution, sensitivity to anthropogenic activities. Uncertainties about changes in aerosol abundance over time translate uncertainties their impact on Earth's climate response air quality policy. One limitation our understanding been lack comprehensive measurements molecular composition volatility, which can elucidate processes affecting abundance. Herein we describe advances the development application Filter Inlet Gases Aerosols (FIGAERO) coupled field-deployable High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometers (HRToF-CIMS). The FIGAERO HRToFCIMS combination broadly probes gas particulate OA by using programmed thermal desorption particles collected Teflon filter with subsequent detection speciation desorbed vapors inherently quantitative selected-ion chemical ionization. provides means obtain insights into volatility components thus physicochemical nature will govern evolution atmosphere.In this Account, discuss design operation FIGAERO, when HRToF-CIMS, characterization molecular-level effective laboratory field. We provide example gleaned from deployment, improve evolution. Specifically, connect profiles equilibrium saturation vapor concentration enthalpy vaporization detected components. also show how HRToF-CIMS environmental simulation chamber experiments field new constraints mechanisms governing secondary formation dynamic associated challenges decomposition during calibration both axis signal. illustrate additional through isothermal evaporation well ultrafine composition. conclude description future opportunities needs ability further science.

Language: Английский

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Exploring the composition and volatility of secondary organic aerosols in mixed anthropogenic and biogenic precursor systems

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(18), P. 14251 - 14273

Published: Sept. 24, 2021

Abstract. Secondary organic aerosol (SOA) formation from mixtures of volatile precursors may be influenced by the molecular interactions components mixture. Here, we report measurements volatility distribution SOA formed photo-oxidation o-cresol, α-pinene, and their mixtures, representative anthropogenic biogenic precursors, in an atmospheric simulation chamber. The combination two independent thermal techniques (thermal denuder, TD, Filter Inlet for Gases Aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer, FIGAERO-CIMS) measure particle volatility, along with detailed gas- particle-phase composition measurements, provides links between mixture resultant volatility. obtained showed substantial discrepancies. TD was wider, spanning across LVOC SVOC range, while respective FIGAERO-CIMS derived using different methods (i.e. calibrated Tmax partitioning calculations) substantially higher (mainly IVOC, respectively) narrow. Although quantification challenging, both similar trends, α-pinene being than that measured o-cresol system, particles those at single-precursor systems. This behaviour could explained opposite effects, scavenging larger molecules lower produced experiments led increase average unique-to-the-mixture products had O:C, MW, OSc‾ and, consequently, compared individual precursors. We further discuss potential limitations quantitative volatilities implications reported results, show changes can qualitatively assessed, caution should taken when linking These results present first observations mixed systems provide analytical context used explore chamber experiments.

Language: Английский

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A review of indoor Gaseous organic compounds and human chemical Exposure: Insights from Real-time measurements

Environment International, Journal Year: 2022, Volume and Issue: 170, P. 107611 - 107611

Published: Nov. 1, 2022

Gaseous organic compounds, mainly volatile compounds (VOCs), have become a wide concern in various indoor environments where we spend the majority of our daily time. The sources, compositions, variations, and sinks VOCs are extremely complex, their potential impacts on human health less understood. Owing to deployment state-of-the-art real-time mass spectrometry during last two decades, understanding dynamic changes chemical transformations indoors has been significantly improved. This review aims summarize key findings from measurements recent studies including residence, classroom, office, sports center, etc. sources sinks, compositions distributions VOCs, factors (e.g., activities, air exchange rate, temperature humidity) driving discussed. physical processes gas-particle partitioning secondary oxidation summarized. Finally, recommendations for future research directions chemistry proposed.

Language: Английский

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Chemistry and human exposure implications of secondary organic aerosol production from indoor terpene ozonolysis

Science Advances, Journal Year: 2022, Volume and Issue: 8(8)

Published: Feb. 25, 2022

Surface cleaning using commercial disinfectants, which has recently increased during the coronavirus disease 2019 pandemic, can generate secondary indoor pollutants both in gas and aerosol phases. It also affect air quality health, especially for workers repeatedly exposed to disinfectants. Here, we cleaned floor of a mechanically ventilated office room cleaner while concurrently measuring gas-phase precursors, oxidants, radicals, oxidation products, aerosols real-time; these were detected within minutes after application. During cleaning, monoterpene concentrations exceeded outdoor by two orders magnitude, increasing rate ozonolysis under low (<10 ppb) ozone levels. High number freshly nucleated sub–10-nm particles (≥10 5 cm −3 ) resulted respiratory tract deposited dose rates comparable or exceeding that inhalation vehicle-associated aerosols.

Language: Английский

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Measurement report: Molecular composition and volatility of gaseous organic compounds in a boreal forest – from volatile organic compounds to highly oxygenated organic molecules

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(11), P. 8961 - 8977

Published: June 14, 2021

Abstract. The molecular composition and volatility of gaseous organic compounds were investigated during April–July 2019 at the Station for Measuring Ecosystem – Atmosphere Relations (SMEAR) II situated in a boreal forest Hyytiälä, southern Finland. In order to obtain more complete picture full understanding ambient (from volatile compounds, VOCs, highly oxygenated molecules, HOMs), two different instruments used. A Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus PTR-ToF; hereafter Vocus) was deployed measure VOCs less (i.e., OVOCs). addition, multi-scheme chemical ionization inlet coupled an atmospheric pressure interface (MION API-ToF) used detect (using Br− as reagent ion; MION-Br) (including HOMs; using NO3- MION-NO3). comparison among measurement techniques revealed that highest elemental oxygen-to-carbon ratios (O : C) observed by MION-NO3 (0.9 ± 0.1, average 1 standard deviation), followed MION-Br (0.8 0.1); lowest O C (0.2 0.1). Diurnal patterns measured found vary techniques, even with same formula, suggesting contributions isomers detected and/or fragmentation from parent inside instruments. Based on complementary information obtained Vocus, MION-Br, MION-NO3, bulk all this obtained. As expected, VOC class most abundant (about 53.2 %), intermediate-volatility (IVOCs, about 45.9 %). Although condensable (low-volatility LVOCs; extremely low ELVOCs; ultralow-volatility ULVOCs) only comprised 0.2 % total they play important role new particle formation shown previous studies forest. Our study shows characterization advantages combining MION API-ToF measuring oxidation extents HOMs). results therefore provide comprehensive well insights into interpreting measurements or testing/improving parameterizations transport climate models.

Language: Английский

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Simulation of Monoterpene SOA Formation by Multiphase Reactions Using Explicit Mechanisms

ACS Earth and Space Chemistry, Journal Year: 2021, Volume and Issue: 5(6), P. 1455 - 1467

Published: May 12, 2021

The formation of terpene secondary organic aerosol (SOA) was simulated using the unified partitioning phase reaction model that predicted multiphase reactions hydrocarbons in presence electrolytic inorganic aerosols. To predict oxygenated products from atmospheric oxidation terpenes, master chemistry mechanism, an explicit gas kinetic implemented. resulting were then classified into 51 lumping groups mass-based stoichiometric coefficients according to their volatility and reactivity. In wet aerosol, SOA approached by liquid–liquid separation between phases due hydrophobicity (oxygen carbon ratios <0.6). streamlined three pathways including gaseous oxidized onto both aqueous phases, oligomerization phase, (acid-catalyzed organosulfate formation). model, peroxy radical autoxidation which is a recently derived mechanism form highly molecules, also included less volatile products. simulation demonstrated for data produced through photo-oxidation different monoterpenes (α-pinene, β-pinene, d-limonene) under various experimental conditions large outdoor photochemical smog chamber. Terpene growth considerably accelerated anchored acidic seeds but much weaker with neutral seeds. This tendency quite isoprene SOA, noticeably grows even phase. Unlike hydrophilic products, are hydrophobic weakly soluble thus, insufficient increase mass. underestimated production polar functional groups, such as −OH, −COOH, −ONO2, compared compositions measured Fourier-transform infrared spectral data. particular, carboxylic acids knowledge gaps mechanisms acid gas-phase in-particle chemistry. Under current emission trends SO2 NOx have been decreasing, suggested reduction sulfate more efficient reduce mass than NOx.

Language: Английский

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Introducing the extended volatility range proton-transfer-reaction mass spectrometer (EVR PTR-MS)

Atmospheric measurement techniques, Journal Year: 2021, Volume and Issue: 14(2), P. 1355 - 1363

Published: Feb. 22, 2021

Abstract. Proton-transfer-reaction mass spectrometry (PTR-MS) is widely used in atmospheric sciences for measuring volatile organic compounds real time. In the most type of PTR-MS instruments, air directly introduced into a chemical ionization reactor via an inlet capillary system. The has volumetric exchange time ∼0.1 s, enabling analyzers to measure at frequency 10 Hz. response does, however, deteriorate if low-volatility analytes interact with surfaces or instrument. Herein, we present extended volatility range (EVR) instrument which mitigates this issue. EVR configuration, capillaries are made passivated stainless steel, and all wetted metal parts surface-passivated functionalized hydrogenated amorphous silicon coating. Heating entire setup (up 120 ∘C) further improves time-response performance. We carried out performance tests on set 29 having saturation concentrations C0 between 10−3 105 µg m−3. 1/e-signal decay times after instant removal analyte from sampling flow were 0.2 90 s gaseous analytes. also tested combination analysis aerosols online (CHARON) particle inlet, 5 35 particulate show example that comparable fastest tube spectrometers currently use. fast can be rapid (∼1 min equilibration time) switching gas measurements. CHARON thus real-time monitoring both organics atmosphere. Finally, rapidly detects highly oxygenated species (with up eight oxygen atoms) particles formed by limonene ozonolysis.

Language: Английский

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Characterization of thermal decomposition of oxygenated organic compounds in FIGAERO-CIMS

Aerosol Science and Technology, Journal Year: 2021, Volume and Issue: 55(12), P. 1321 - 1342

Published: June 22, 2021

The Filter Inlet for Gases and AEROsols coupled with a chemical ionization mass spectrometer (FIGAERO-CIMS) measures particle-phase organics via temperature-programmed thermal desorption, though the extent to which different compounds undergo decomposition is not well characterized. We study effect of functional groups on degree pathways (decarboxylation dehydration) in FIGAERO-CIMS using atmospherically relevant alcohols, monoacids, diacids, polyacids, multifunctional acids. Based their carbon oxidation state, are categorized as less-oxidized oxygenated organic aerosol (LO-OOA), (OOA), or more-oxidized OOA (MO-OOA), exhibit little, minor, considerable decomposition, respectively. result shows that leads negative biases measured elemental ratios (O:C H:C) MO-OOA, except H:C ratio those MO-OOA. develop screening criteria double bond equivalent (DBE), maximum desorption temperature (Tmax), number oxygen (nO) (DBE ≥ 2, Tmax 72 °C, nO > 4). Additionally, we find β-keto-carboxylic acids carboxyl-containing aromatic only favor decarboxylation. Lastly, investigate instrument's ramping rate (40, 13.3, 3.3 °C min−1) citric acid. recommend 13.3 40 min−1 rates but do acts distinctively from most parental compound decomposition.Copyright © 2021 American Association Aerosol Research

Language: Английский

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The importance of sesquiterpene oxidation products for secondary organic aerosol formation in a springtime hemiboreal forest

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(15), P. 11781 - 11800

Published: Aug. 6, 2021

Abstract. Secondary organic aerosols (SOAs) formed from biogenic volatile compounds (BVOCs) constitute a significant fraction of atmospheric particulate matter and have been recognized to significantly affect the climate air quality. Atmospheric SOA mass yields chemical composition result complex mixture oxidation products originating diversity BVOCs. Many laboratory field experiments studied particle formation growth in recent years. However, large uncertainty still remains regarding contribution BVOCs SOA. In particular, sesquiterpenes not thoroughly investigated, their poorly characterized. this study, Filter Inlet for Gases Aerosols (FIGAERO) combined with high-resolution time-of-flight ionization spectrometer (CIMS), iodide ionization, was used simultaneous measurement gas-phase particle-phase oxygenated compounds. The aim study evaluate relative sesquiterpene springtime hemiboreal forest environment. Our results revealed that monoterpene were main contributors particles. particles compared times when either or dominant possible key identified both situations. Surprisingly, predominant phase some periods, while concentrations remained much lower than those products. This can be explained by favorable effective partitioning into phase. volatility determined measured thermograms increased concentration higher monoterpenes. Overall, demonstrates may an important role chemistry, particular during spring recovery period.

Language: Английский

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