Measurement of the gas-phase/particle-phase partitioning of particle-adsorbed chemical compounds

2000 ◽  
Vol 31 ◽  
pp. 325-326 ◽  
Author(s):  
U. Risse ◽  
A. Kettrup
Keyword(s):  
Gas Phase ◽  
Phase Particle ◽  
Chemical Compounds ◽  
Particle Phase ◽  
Phase Partitioning

Strong deviations from thermodynamically expected phase partitioning of organic acids during one year of rural field measurements 

2021 ◽  
Author(s):  
Andreas Tilgner ◽  
Bastian Stieger ◽  
Dominik van Pinxteren ◽  
Gerald Spindler ◽  
Laurent Poulain ◽  
...  
Keyword(s):  
Organic Acids ◽  
Gas Phase ◽  
Methanesulfonic Acid ◽  
Field Measurements ◽  
Ambient Air ◽  
Water Soluble ◽  
Particle Phase ◽  
Organic Salts ◽  
Phase Partitioning ◽  
One Year

<p>Organic acids are ubiquitous compounds in the troposphere and can affect human health, the climate, air quality, and the linked ecosystems. Depending on their solubility and volatility, they can partition in both gas phase and in the particle phase. In the particle phase, organic acids partly represent about 10% of the water-soluble organic matter. However, their partitioning between different phases is not fully understood yet. Therefore, an upgraded monitor for aerosols and gases in ambient air (MARGA) was applied for one year at the Central European TROPOS research site Melpitz to study the gas- and particle-phase partitioning of formic, acetic, propionic, butyric, glycolic, pyruvic, oxalic, malonic, succinic, malic, and methanesulfonic acid (MSA). Measured gas- and PM<sub>10</sub> particle-phase mean concentrations were 12−445 and 7−31 ng m<sup>-3</sup> for monocarboxylic acids (MCAs), between 0.6−8 and 4−31 ng m<sup>-3</sup> for dicarboxylic acids (DCAs), and 2 and 31 ng m<sup>-3</sup> for MSA, respectively. Assuming full dissolution in nonideal aerosol solutions, empirical noneffective Henry’s law constants (H<sub>emp</sub>) were calculated and compared with literature values (H<sub>lit</sub>). Calculated mean H<sub>emp</sub> were 4.5 × 10<sup>9</sup>−2.2 × 10<sup>10</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for MCAs, 3.6 × 10<sup>10</sup>−7.5 × 10<sup>11</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for DCAs, and 7.5 × 10<sup>7</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for MSA and, thus, factors of 5.1 × 10<sup>3</sup>−9.1 × 10<sup>5</sup> and 2.5−20.3 higher than their corresponding H<sub>lit</sub> for MCAs and DCAs, respectively, and 9.0 × 10<sup>−5</sup> lower than H<sub>lit,MSA</sub>. Data analyses and thermodynamic calculations implicate that the formation of chemical association complexes and organic salts inhibits the partitioning of organic acids toward the gas phase and, thus, at least partly explains higher H<sub>emp</sub> values for both MCAs and summertime DCAs. Low H<sub>emp,MSA</sub> are also unexpected because of the high MSA solubility and are reported for the first time in this study. Overall, the results of the present study implicate that processes responsible for the observed stronger partitioning of carboxylic acids toward the particle phase need to be further investigated and accounted for in complex multiphase chemistry models as they affect the contribution of organic acids to secondary organic aerosol mass, their chemical processing, and lifetime.</p> <p> </p> <p> </p>

Characterization of 56 airborne persistent organic pollutants (POPs) in gas-phase and particle-phase

2021 ◽  
pp. 1-13
Author(s):  
Li Tan ◽  
Ning Wang ◽  
Yingjian Dong ◽  
Siyuan Li ◽  
Xuehan Wang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Particle Phase

scholarly journals Polyfluoroalkyl compounds in the Canadian Arctic atmosphere

2011 ◽  
Vol 8 (4) ◽  
pp. 399 ◽  
Author(s):  
Lutz Ahrens ◽  
Mahiba Shoeib ◽  
Sabino Del Vento ◽  
Garry Codling ◽  
Crispin Halsall
Keyword(s):  
Gas Phase ◽  
Environmental Concern ◽  
Canadian Arctic ◽  
High Volume ◽  
Ambient Air ◽  
Coast Guard ◽  
The Arctic ◽  
Particle Phase ◽  
Method Performance ◽  
Arctic Atmosphere

Environmental contextPerfluoroalkyl compounds are of rising environmental concern because of their ubiquitous distribution in remote regions like the Arctic. The present study quantifies these contaminants in the gas and particle phases of the Canadian Arctic atmosphere. The results demonstrate the important role played by gas–particle partitioning in the transport and fate of perfluoroalkyl compounds in the atmosphere. AbstractPolyfluoroalkyl compounds (PFCs) were determined in high-volume air samples during a ship cruise onboard the Canadian Coast Guard Ship Amundsen crossing the Labrador Sea, Hudson Bay and the Beaufort Sea of the Canadian Arctic. Five PFC classes (i.e. perfluoroalkyl carboxylates (PFCAs), polyfluoroalkyl sulfonates (PFSAs), fluorotelomer alcohols (FTOHs), fluorinated sulfonamides (FOSAs), and sulfonamidoethanols (FOSEs)) were analysed separately in the gas phase collected on PUF/XAD-2 sandwiches and in the particle phase on glass-fibre filters (GFFs). The method performance of sampling, extraction and instrumental analysis were compared between two research groups. The FTOHs were the dominant PFCs in the gas phase (20–138 pg m–3), followed by the FOSEs (0.4–23 pg m–3) and FOSAs (0.5–4.7 pg m–3). The PFCAs could only be quantified in the particle phase with low levels (<0.04–0.18 pg m–3). In the particle phase, the dominant PFC class was the FOSEs (0.3–8.6 pg m–3). The particle-associated fraction followed the general trend of: FOSEs (~25 %) > FOSAs (~9 %) > FTOHs (~1 %). Significant positive correlation between ∑FOSA concentrations in the gas phase and ambient air temperature indicate that cold Arctic surfaces, such as the sea-ice snowpack and surface seawater could be influencing FOSAs in the atmosphere.

scholarly journals Evaluation of the chemical composition of gas- and particle-phase products of aromatic oxidation

2020 ◽  
Vol 20 (16) ◽  
pp. 9783-9803
Author(s):  
Archit Mehra ◽  
Yuwei Wang ◽  
Jordan E. Krechmer ◽  
Andrew Lambe ◽  
Francesca Majluf ◽  
...  
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer ◽  
Urban Areas ◽  
Minor Component ◽  
Proton Transfer Reaction ◽  
Chemical Mechanism ◽  
Particle Phase ◽  
Experimental Conditions ◽  
Radical Oxidation ◽  
Product Ions

Abstract. Aromatic volatile organic compounds (VOCs) are key anthropogenic pollutants emitted to the atmosphere and are important for both ozone and secondary organic aerosol (SOA) formation in urban areas. Recent studies have indicated that aromatic hydrocarbons may follow previously unknown oxidation chemistry pathways, including autoxidation that can lead to the formation of highly oxidised products. In this study we evaluate the gas- and particle-phase ions measured by online mass spectrometry during the hydroxyl radical oxidation of substituted C9-aromatic isomers (1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, propylbenzene and isopropylbenzene) and a substituted polyaromatic hydrocarbon (1-methylnaphthalene) under low- and medium-NOx conditions. A time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) with iodide–anion ionisation was used with a filter inlet for gases and aerosols (FIGAERO) for the detection of products in the particle phase, while a Vocus proton-transfer-reaction mass spectrometer (Vocus-PTR-MS) was used for the detection of products in the gas phase. The signal of product ions observed in the mass spectra were compared for the different precursors and experimental conditions. The majority of mass spectral product signal in both the gas and particle phases comes from ions which are common to all precursors, though signal distributions are distinct for different VOCs. Gas- and particle-phase composition are distinct from one another. Ions corresponding to products contained in the near-explicit gas phase Master Chemical Mechanism (MCM version 3.3.1) are utilised as a benchmark of current scientific understanding, and a comparison of these with observations shows that the MCM is missing a range of highly oxidised products from its mechanism. In the particle phase, the bulk of the product signal from all precursors comes from ring scission ions, a large proportion of which are more oxidised than previously reported and have undergone further oxidation to form highly oxygenated organic molecules (HOMs). Under the perturbation of OH oxidation with increased NOx, the contribution of HOM-ion signals to the particle-phase signal remains elevated for more substituted aromatic precursors. Up to 43 % of product signal comes from ring-retaining ions including HOMs; this is most important for the more substituted aromatics. Unique products are a minor component in these systems, and many of the dominant ions have ion formulae concurrent with other systems, highlighting the challenges in utilising marker ions for SOA.

Gas-phase kinetics modifies the CCN activity of a biogenic SOA

2018 ◽  
Vol 20 (9) ◽  
pp. 6591-6597
Author(s):  
A. E. Vizenor ◽  
A. A. Asa-Awuku
Keyword(s):  
Particle Size ◽  
Thermodynamic Properties ◽  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Cloud Condensation Nuclei ◽  
Organic Aerosol ◽  
Aerosol Composition ◽  
Phase Partitioning ◽  
Gas Phase Kinetics ◽  
Ccn Activity

Cloud condensation nuclei (CCN) activity and the hygroscopicity of secondary organic aerosol (SOA) depends on the particle size and composition, explicitly, the thermodynamic properties of the aerosol solute and subsequent interactions with water. The gas-to-aerosol phase partitioning is critical for aerosol composition and thus gas-phase vapors and kinetics can play an important role in the CCN activity of SOA.

scholarly journals Development of aroCACM/MPMPO 1.0: a model to simulate secondary organic aerosol from aromatic precursors in regional models

2016 ◽  
Vol 9 (6) ◽  
pp. 2143-2151 ◽  
Author(s):  
Matthew L. Dawson ◽  
Jialu Xu ◽  
Robert J. Griffin ◽  
Donald Dabdub
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Secondary Organic Aerosol ◽  
Three Dimensional ◽  
Organic Aerosol ◽  
Phase Partitioning ◽  
California Institute Of Technology ◽  
Institute Of Technology ◽  
Three Dimensional Models

Abstract. The atmospheric oxidation of aromatic compounds is an important source of secondary organic aerosol (SOA) in urban areas. The oxidation of aromatics depends strongly on the levels of nitrogen oxides (NOx). However, details of the mechanisms by which oxidation occurs have only recently been elucidated. Xu et al. (2015) developed an updated version of the gas-phase Caltech Atmospheric Chemistry Mechanism (CACM) designed to simulate toluene and m-xylene oxidation in chamber experiments over a range of NOx conditions. The output from such a mechanism can be used in thermodynamic predictions of gas–particle partitioning leading to SOA. The current work reports the development of a model for SOA formation that combines the gas-phase mechanism of Xu et al. (2015) with an updated lumped SOA-partitioning scheme (Model to Predict the Multi-phase Partitioning of Organics, MPMPO) that allows partitioning to multiple aerosol phases and that is designed for use in larger-scale three-dimensional models. The resulting model is termed aroCACM/MPMPO 1.0. The model is integrated into the University of California, Irvine – California Institute of Technology (UCI-CIT) Airshed Model, which simulates the South Coast Air Basin (SoCAB) of California. Simulations using 2012 emissions indicate that “low-NOx” pathways to SOA formation from aromatic oxidation play an important role, even in regions that typically exhibit high-NOx concentrations.

scholarly journals Distributions and sources of low-molecular-weight monocarboxylic acids in gas and particles from a deciduous broadleaf forest in northern Japan

2019 ◽  
Vol 19 (4) ◽  
pp. 2421-2432 ◽  
Author(s):  
Tomoki Mochizuki ◽  
Kimitaka Kawamura ◽  
Yuzo Miyazaki ◽  
Bhagawati Kunwar ◽  
Suresh Kumar Reddy Boreddy
Keyword(s):  
Molecular Weight ◽  
Gas Phase ◽  
Nonanoic Acid ◽  
Low Molecular Weight ◽  
Forest Site ◽  
Particle Phase ◽  
Broadleaf Forest ◽  
Monocarboxylic Acids ◽  
Deciduous Broadleaf Forest ◽  
Northern Japan

Abstract. To better understand the distributions and sources of low-molecular-weight (LMW) monocarboxylic acids (monoacids) in the forest atmosphere, we conducted simultaneous collection of gaseous and particulate samples at a deciduous broadleaf forest site in northern Japan. LMW normal (C1–C10), branched (iC4–iC6), hydroxyl (glycolic and lactic) and aromatic (benzoic) monoacids were detected in the gas and particle phases. The dominant LMW monoacids in gas phase were formic (mean: 953 ng m−3) and acetic (528 ng m−3) acids followed by propionic (37 ng m−3) or isopentanoic (42 ng m−3) acid. In the particle phase, isopentanoic (159 ng m−3) was dominant, followed by acetic (104 ng m−3) and formic (71 ng m−3) or lactic (65 ng m−3) acids. Concentrations of LMW monoacids did not show correlations with anthropogenic tracers such as nss-SO42- and NO3-, indicating that anthropogenic contribution is not important. Concentrations of C1–C6 monoacids in the gas phase showed positive correlations (r2=0.21–0.91) with isobutyric acid (iC4), which may be produced by microbial activity in soil. The forest soil may be a source of gaseous C1–C6 monoacids in the forest atmosphere. Acetic acid in the particle phase positively correlated with nonanoic acid (C9) (r2=0.63), suggesting that formation of acetic and nonanoic acids is associated with the oxidation of biogenic unsaturated fatty acids in the aerosol phase, in addition to photochemical oxidation of biogenic volatile organic compounds. The particle-phase fractions (Fp) of formic and acetic acids showed negative correlation with ambient temperature (C1: r2=0.49, C2: r2=0.60) but showed positive correlation with relative humidity (C1: r2=0.30, C2: r2=0.55) in daytime, suggesting that these meteorological parameters are important for the gas and particle portioning of monoacids in the forest atmosphere.

scholarly journals Formation of Highly Oxygenated Low-Volatility Products from Cresol Oxidation

2016 ◽  
Author(s):  
Rebecca H. Schwantes ◽  
Katherine A. Schilling ◽  
Renee C. McVay ◽  
Hanna Lignell ◽  
Matthew M. Coggon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Ring Opening ◽  
Chemical Ionization ◽  
First Generation ◽  
Direct Analysis ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Ionization Mass ◽  
Particle Phase

Abstract. Hydroxyl radical (OH) oxidation of toluene produces the ring-retaining products cresol and benzaldehyde, and the ring-opening products bicyclic intermediate compounds and epoxides. Here, first- and later-generation OH oxidation products from cresol and benzaldehyde are identified in laboratory chamber experiments. For benzaldehyde, first-generation ring-retaining products are identified, but later-generation products are not detected. For cresol, low-volatility (saturation mass concentration, C* ~ 3.5 × 104–7.7 × 10−3 μg m−3) first- and later-generation ring-retaining products are identified. Subsequent OH addition to the aromatic ring of o-cresol leads to compounds such as hydroxy, dihydroxy, and trihydroxy methyl benzoquinones and dihydroxy, trihydroxy, tetrahydroxy, and pentahydroxy toluenes. These products are detected in the gas phase by chemical ionization mass spectrometry (CIMS) and in the particle phase using offline direct analysis in real time mass spectrometry (DART-MS). Our data suggest that the yield of trihydroxy toluene from dihydroxy toluene is substantial. While an exact yield cannot be reported as authentic standards are unavailable, we find that a yield for trihydroxy toluene from dihydroxy toluene of ~ 0.7 (equal to the yield of dihydroxy toluene from o-cresol) is consistent with experimental results for o-cresol oxidation under low-NO conditions. These results suggest that even though the cresol pathway accounts for only ~ 20 % of the oxidation products of toluene, it is the source of a significant fraction (~ 20–40 %) of toluene secondary organic aerosol (SOA) due to the formation of low-volatility products.

scholarly journals An Analysis of the Effect of System Variables on the Quality of Thin Films and Powders Produced by Laser-Breakdown Chemical Vapor Deposition

1987 ◽  
Vol 101 ◽  
Author(s):  
E.L. Joyce ◽  
T.R. Jervis
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Dielectric Breakdown ◽  
Phase Particle ◽  
Metastable Phase ◽  
Rapid Quenching ◽  
Large Area ◽  
Laser Breakdown ◽  
System Pressure ◽  
System Variables

ABSTRACTA gas phase process for large area depositions on an ambient temperature substrate using laser-induced dielectric breakdown of gas phase precursors has recently been developed.1 Deposits of nickel alloys show excellent grain refinement (<10 nm) and metastable phase incorporation due to rapid quenching from the gas phase. Particle size distribution and compositional variance within the deposited films have been studied using electron microscopy and electron diffraction. Kinetic expressions to explain homogeneous gas phase nucleation and growth of the deposited materials have been developed in an effort to better understand this process. The effect of system variables on film and powder grain sizes has been studied. This analysis gives insight into the fluid flow/heat transfer patterns involved in the system and their effect on the final deposited material. The effect of system pressure, gas phase composition, and laser pulse energy, on particle size, surface area coverage, and deposition thickness are discussed.

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