151
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Xia AG, Michelangeli DV, Makar PA. Box model studies of the secondary organic aerosol formation under different HC/NOxconditions using the subset of the Master Chemical Mechanism forα-pinene oxidation. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd008726] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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152
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Capouet M, Müller JF, Ceulemans K, Compernolle S, Vereecken L, Peeters J. Modeling aerosol formation in alpha-pinene photo-oxidation experiments. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd008995] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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153
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Narukawa M, Matsumi Y, Matsumoto J, Takahashi K, Yabushita A, Sato K, Imamura T. Single Particle Analysis of Secondary Organic Aerosols Formed from 1,4-Cyclohexadiene Ozonolysis Using a Laser-Ionization Single-Particle Aerosol Mass Spectrometer. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2008. [DOI: 10.1246/bcsj.81.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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154
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Prather KA, Hatch CD, Grassian VH. Analysis of atmospheric aerosols. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2008; 1:485-514. [PMID: 20636087 DOI: 10.1146/annurev.anchem.1.031207.113030] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Aerosols represent an important component of the Earth's atmosphere. Because aerosols are composed of solid and liquid particles of varying chemical complexity, size, and phase, large challenges exist in understanding how they impact climate, health, and the chemistry of the atmosphere. Only through the integration of field, laboratory, and modeling analysis can we begin to unravel the roles atmospheric aerosols play in these global processes. In this article, we provide a brief review of the current state of the science in the analysis of atmospheric aerosols and some important challenges that need to be overcome before they can become fully integrated. It is clear that only when these areas are effectively bridged can we fully understand the impact that atmospheric aerosols have on our environment and the Earth's system at the level of scientific certainty necessary to design and implement sound environmental policies.
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Affiliation(s)
- Kimberly A Prather
- Department of Chemistry and Biochemistry, Scripps Institution of Oceanography, University of California, San Diego, 92093-0314, USA.
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155
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156
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King MD, Thompson KC, Ward AD, Pfrang C, Hughes BR. Oxidation of biogenic and water-soluble compounds in aqueous and organic aerosol droplets by ozone: a kinetic and product analysis approach using laser Raman tweezers. Faraday Discuss 2008; 137:173-92; discussion 193-204. [DOI: 10.1039/b702199b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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157
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Liao KJ, Tagaris E, Manomaiphiboon K, Napelenok SL, Woo JH, He S, Amar P, Russell AG. Sensitivities of ozone and fine particulate matter formation to emissions under the impact of potential future climate change. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:8355-8361. [PMID: 18200863 DOI: 10.1021/es070998z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Impact of climate change alone and in combination with currently planned emission control strategies are investigated to quantify effectiveness in decreasing regional ozone and PM2.5 over the continental U.S. using MM5, SMOKE, and CMAQ with DDM-3D. Sensitivities of ozone and PM2.5 formation to precursor emissions are found to change only slightly in response to climate change. In many cases, mass per ton sensitivities to NO(x) and SO2 controls are predicted to be greater in the future due to both the lower emissions as well as climate, suggesting that current control strategies based on reducing such emissions will continue to be effective in decreasing ground-level ozone and PM2.5 concentrations. SO2 emission controls are predicted to be most beneficial for decreasing summertime PM2.5 levels, whereas controls of NO(x) emissions are effective in winter. Spatial distributions of sensitivities are also found to be only slightly affected assuming no changes in land-use. Contributions of biogenic VOC emissions to PM2.5 formation are simulated to be more important in the future because of higher temperatures, higher biogenic emissions, and lower anthropogenic NO(x) and SO2 emissions.
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Affiliation(s)
- Kuo-Jen Liao
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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158
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Gu X, Zhang F, Guo Y, Kaiser R. Crossed-Molecular-Beam Study on the Formation of Phenylacetylene from Phenyl Radicals and Acetylene. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701890] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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159
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Gu X, Zhang F, Guo Y, Kaiser RI. Crossed-Molecular-Beam Study on the Formation of Phenylacetylene from Phenyl Radicals and Acetylene. Angew Chem Int Ed Engl 2007; 46:6866-9. [PMID: 17640021 DOI: 10.1002/anie.200701890] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Xibin Gu
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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160
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Zhang F, Gu X, Guo Y, Kaiser RI. Reaction Dynamics on the Formation of Styrene: A Crossed Molecular Beam Study of the Reaction of Phenyl Radicals with Ethylene. J Org Chem 2007; 72:7597-604. [PMID: 17784772 DOI: 10.1021/jo071006a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction dynamics of phenyl radicals (C6H5) with ethylene (C2H4) and D4-ethylene (C2D4) were investigated at two collision energies of 83.6 and 105.3 kJ mol-1 utilizing a crossed molecular beam setup. The experiments suggested that the reaction followed indirect scattering dynamics via complex formation and was initiated by an addition of the phenyl radical to the carbon-carbon double bond of the ethylene molecule forming a C6H5CH2CH2 radical intermediate. Under single collision conditions, this short-lived transient species was found to undergo unimolecular decomposition via atomic hydrogen loss through a tight exit transitions state to synthesize the styrene molecule (C6H5C2H3). Experiments with D4-ethylene verified that in the corresponding reaction with ethylene the hydrogen atom was truly emitted from the ethylene unit but not from the phenyl moiety. The overall reaction to form styrene plus atomic hydrogen from the reactants was found to be exoergic by 25 +/- 12 kJ mol(-1). This study provides solid evidence that in combustion flames the styrene molecule, a crucial precursor to form polycyclic aromatic hydrocarbons (PAHs), can be formed within a single neutral-neutral collision, a long-standing theoretical prediction which has remained to be confirmed by laboratory experiments under well-defined single collision conditions for the last 50 years.
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Affiliation(s)
- F Zhang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, USA
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161
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Prenni AJ, Petters MD, Kreidenweis SM, DeMott PJ, Ziemann PJ. Cloud droplet activation of secondary organic aerosol. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007963] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anthony J. Prenni
- Department of Atmospheric Science; Colorado State University; Fort Collins Colorado USA
| | - Markus D. Petters
- Department of Atmospheric Science; Colorado State University; Fort Collins Colorado USA
| | - Sonia M. Kreidenweis
- Department of Atmospheric Science; Colorado State University; Fort Collins Colorado USA
| | - Paul J. DeMott
- Department of Atmospheric Science; Colorado State University; Fort Collins Colorado USA
| | - Paul J. Ziemann
- Air Pollution Research Center; University of California; Riverside USA
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162
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Kroll JH, Chan AWH, Ng NL, Flagan RC, Seinfeld JH. Reactions of semivolatile organics and their effects on secondary organic aerosol formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:3545-50. [PMID: 17547176 DOI: 10.1021/es062059x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Secondary organic aerosol (SOA) constitutes a significant fraction of total atmospheric particulate loading, but there is evidence that SOA yields based on laboratory studies may underestimate atmospheric SOA. Here we present chamber data on SOA growth from the photooxidation of aromatic hydrocarbons, finding that SOA yields are systematically lower when inorganic seed particles are not initially present. This indicates that concentrations of semivolatile oxidation products are influenced by processes beyond gas-particle partitioning, such as chemical reactions and/or loss to chamber walls. Predictions of a kinetic model in which semivolatile compounds may undergo reactions in both the gas and particle phases in addition to partitioning are qualitatively consistent with the observed seed effect, as well as with a number of other recently observed features of SOA formation chemistry. The behavior arises from a kinetic competition between uptake to the particle phase and reactive loss of the semivolatile product. It is shown that when hydrocarbons react in the absence of preexisting organic aerosol, such loss processes may lead to measured SOA yields lower than would occur under atmospheric conditions. These results underscore the need to conduct studies of SOA formation in the presence of atmospherically relevant aerosol loadings.
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Affiliation(s)
- Jesse H Kroll
- Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, California 91125, USA
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163
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Stanier CO, Pathak RK, Pandis SN. Measurements of the volatility of aerosols from alpha-pinene ozonolysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:2756-63. [PMID: 17533835 DOI: 10.1021/es0519280] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The temperature-dependence of secondary organic aerosol (SOA) concentrations is measured using a temperature-controlled smog chamber. Aerosols are generated from reaction of alpha-pinene (14-150 ppb) and ozone at a constant temperature of 22 +/- 2 degrees C in the presence of the OH-scavenger 2-butanol. After the reactions are completed the chamber is heated or cooled in a range from 20 to 40 degrees C. SOA volume concentrations increase at temperatures below the initial formation temperature and decrease at elevated temperatures. The response to the temperature change as measured by percent mass change per degree ranged from -0.4 to -3.6% K(-1), for a total mass reduction of 5-60% upon heating from 22 to 35 degrees C. The reported range is due to two factors: (1) experimental uncertainty, arising mainly from uncertainty in evaporation and condensation behavior of particles lost to the chamber wall; (2) differences in the temperature response from experiment to experiment. Aerosol temperature sensitivity was also measured by tandem differential mobility analysis (TDMA) where similarly generated SOA were heated from 20 to 25 degrees C to 30-40 degrees C with residence times of 0.5-1.5 min, resulting in particle volume reductions of up to 20%. The TDMA experiments indicate that evaporation of the SOA particles in this system occurs with a potentially significant mass transfer limitation (e.g., accommodation coefficient <0.1).
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Affiliation(s)
- Charles O Stanier
- Chemical and Biochemical Engineering Dept., University of Iowa, Iowa City, Iowa 52242, USA.
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164
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Shilling JE, King SM, Mochida M, Worsnop DR, Martin ST. Mass Spectral Evidence That Small Changes in Composition Caused by Oxidative Aging Processes Alter Aerosol CCN Properties. J Phys Chem A 2007; 111:3358-68. [PMID: 17394294 DOI: 10.1021/jp068822r] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative processing (i.e., "aging") of organic aerosol particles in the troposphere affects their cloud condensation nuclei (CCN) activity, yet the chemical mechanisms remain poorly understood. In this study, oleic acid aerosol particles were reacted with ozone while particle chemical composition and CCN activity were simultaneously monitored. The CCN activated fraction at 0.66 +/- 0.06% supersaturation was zero for 200 nm mobility diameter particles exposed to 565 to 8320 ppmv O3 for less than 30 s. For greater exposure times, however, the particles became CCN active. The corresponding chemical change shown in the particle mass spectra was the oxidation of aldehyde groups to form carboxylic acid groups. Specifically, 9-oxononanoic acid was oxidized to azelaic acid, although the azelaic acid remained a minor component, comprising 3-5% of the mass in the CCN-inactive particles compared to 4-6% in the CCN-active particles. Similarly, the aldehyde groups of alpha-acyloxyalkylhydroperoxide (AAHP) products were also oxidized to carboxylic acid groups. On a mass basis, this conversion was at least as important as the increased azelaic acid yield. Analysis of our results with Köhler theory suggests that an increase in the water-soluble material brought about by the aldehyde-to-carboxylic acid conversion is an insufficient explanation for the increased CCN activity. An increased concentration of surface-active species, which decreases the surface tension of the aqueous droplet during activation, is an interpretation consistent with the chemical composition observations and Köhler theory. These results suggest that small changes in particle chemical composition caused by oxidation could increase the CCN activity of tropospheric aerosol particles during their atmospheric residence time.
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Affiliation(s)
- J E Shilling
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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165
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Liao H, Henze DK, Seinfeld JH, Wu S, Mickley LJ. Biogenic secondary organic aerosol over the United States: Comparison of climatological simulations with observations. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007813] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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166
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Pathak RK, Stanier CO, Donahue NM, Pandis SN. Ozonolysis ofα-pinene at atmospherically relevant concentrations: Temperature dependence of aerosol mass fractions (yields). ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007436] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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167
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McNeill VF, Wolfe GM, Thornton JA. The Oxidation of Oleate in Submicron Aqueous Salt Aerosols: Evidence of a Surface Process. J Phys Chem A 2007; 111:1073-83. [PMID: 17243657 DOI: 10.1021/jp066233f] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have studied the oxidation of submicron aqueous aerosols consisting of internal mixtures of sodium oleate (oleic acid proxy), sodium dodecyl sulfate, and inorganic salts by O3, NO3/N2O5, and OH. Experiments were performed using an aerosol flow tube and a continuous flow photochemical reaction chamber coupled to a chemical ionization mass spectrometer (CIMS). The CIMS was fitted with a heated inlet for volatilization and detection of organics in the particle phase simultaneously with the gas phase. A differential mobility analyzer/condensation particle counter was used for determining aerosol size distributions. The oxidation of oleate by O3 follows Langmuir-Hinshelwood kinetics, with gammaO3 approximately 10(-5) calculated from the observed loss rate of oleate in the particle phase. The best fit Langmuir-Hinshelwood parameters are kImax=0.05+/-0.01 s-1 and KO3=4(+/-3)x10(-14) cm3molec-1. These parameters showed no dependence on the ionic composition of the aerosols or on the presence of alkyl surfactants. Several ozone oxidation products were observed to be particle-bound at ambient temperature, including nonanoic acid. We observed efficient processing of oleate by OH (0.1<or=gammaOH<or=1), and we suggest an upper bound of gammaNuOmicron3<10(-3). We conclude that for the aerosol compositions studied, oxidation occurs near the gas-aerosol interface and that the 1 e-fold lifetime of unsaturated organics at the aerosol surface is approximately 10 min due to O3 oxidation under atmospheric conditions. In the context of a Langmuir-Hinshelwood mechanism, different underlying aerosol compositions may extend the lifetime of oleic acid at the surface by reducing KO3.
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Affiliation(s)
- V Faye McNeill
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, USA
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168
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Hung HM, Ariya P. Oxidation of Oleic Acid and Oleic Acid/Sodium Chloride(aq) Mixture Droplets with Ozone: Changes of Hygroscopicity and Role of Secondary Reactions. J Phys Chem A 2007; 111:620-32. [PMID: 17249752 DOI: 10.1021/jp0654563] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The heterogeneous reactions of oleic acid (OL) and oleic-acid/sodium-chloride(aq) (OL/NaCl(aq)) mixture droplets with ozone are studied at two relative humidities (RH). The reactions were monitored concomitantly using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR) for the organic species and UV-vis spectrometry for the ozone concentration in order to investigate reaction rate discrepancies reported in literature as well as the oxidation mechanism. The less volatile products were identified and resolved by a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS). This led to identification of 13 organic molecules (up to 45 carbons). Identified products were predominantly composed by nananoic acid and azelaic acid. Our results suggest that the propagation reaction is possibly initiated by a secondary reaction such as the stabilized Criegee intermediates reacting with oleic acid. For hygroscopic properties, the ATR-IR spectra at high RH (87 +/- 5%) showed that the hydrophobic oleic acid droplets can take up water slightly when exposed to ozone. For internally mixed OL/NaCl(aq) droplets, the hygroscopic properties of the droplets upon ozone exposure were found to be complex; hygroscopic properties or the growth factors of the droplets are altered as the oxidation products of oleic acid exist concurrently with NaCl(aq). Furthermore, the concentration of ozone was monitored to examine the kinetics of the oxidation reaction. The integrated ozone profile recorded by UV-vis spectrometry showed the consumed ozone represents only 30 +/- 2% of total oleic acid and hence confirmed the existence of secondary reactions. A kinetic model was used to simulate an ozone temporal profile that could only be described if the secondary reactions were included. The discrepancy of ozone uptake coefficients according to the OL and ozone measurements as well as their atmospheric implications are herein discussed.
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Affiliation(s)
- Hui-Ming Hung
- Department of Atmospheric and Oceanic Sciences, 805 Sherbrooke Street West, Montreal QC H3A 2T5, Canada.
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169
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Narukawa M, Matsumi Y, Matsumoto J, Takahashi K, Yabushita A, Sato K, Imamura T. Real-Time Analysis of Secondary Organic Aerosol Particles Formed from Cyclohexene Ozonolysis Using a Laser-Ionization Single-Particle Aerosol Mass Spectrometer. ANAL SCI 2007; 23:507-12. [PMID: 17495392 DOI: 10.2116/analsci.23.507] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A real-time analysis of secondary organic aerosol (SOA) particles formed from cyclohexene ozonolysis in a smog chamber was performed using a laser-ionization single-particle aerosol mass spectrometer (LISPA-MS). The instrument obtains both size and chemical compositions of individual aerosol particles with a high time-resolution (approximately 2 s at the maximum). Both positive and negative-ion mass spectra are obtained. Standard particles generated from dicarboxylic acid solutions using an atomizer were also analyzed. For both standard and SOA particles, the negative-ion mass spectra provided information about the molecular weights of the organic compounds in the particles, since the intense ions in the negative-ion mass spectra are mainly attributable to the molecular-related ions [M-H]-. It was demonstrated that the real-time single-particle analysis of SOA particles by the LISPA-MS technique can reveal the formation and transformation processes of SOA particle in smog chambers.
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170
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Pól J, Hohnová B, Jussila M, Hyötyläinen T. Comprehensive two-dimensional liquid chromatography–time-of-flight mass spectrometry in the analysis of acidic compounds in atmospheric aerosols. J Chromatogr A 2006; 1130:64-71. [PMID: 16725147 DOI: 10.1016/j.chroma.2006.04.050] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Revised: 04/05/2006] [Accepted: 04/06/2006] [Indexed: 12/01/2022]
Abstract
A novel method utilising comprehensive two-dimensional liquid chromatography interfaced to electrospray ionisation time-of-flight mass spectrometry was developed for the determination of organic acids in atmospheric aerosols. The system was applied to the analysis of methanolic extracts of filters from a high volume sampler. The enhanced separation power of two-dimensional separation was demonstrated in the analysis of both rural and urban samples. Quantification was performed for compounds for which standards were available. Limit of detection was 2-200 ng/ml. Average reproducibility of retention times in each dimensions was 0.1%, and average reproducibility of peak areas was 8% (10 microg/ml, n=3).
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Affiliation(s)
- Jaroslav Pól
- Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014, Helsinki, Finland
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171
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Chiappini L, Perraudin E, Durand-Jolibois R, Doussin JF. Development of a supercritical fluid extraction-gas chromatography-mass spectrometry method for the identification of highly polar compounds in secondary organic aerosols formed from biogenic hydrocarbons in smog chamber experiments. Anal Bioanal Chem 2006; 386:1749-59. [PMID: 16972055 DOI: 10.1007/s00216-006-0744-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 08/04/2006] [Accepted: 08/08/2006] [Indexed: 10/24/2022]
Abstract
A new one-step method for the analysis of highly polar components of secondary organic aerosols (SOA) has been developed. This method should lead to a better understanding of SOA formation and evolution since it enables the compounds responsible for SOA formation to be identified. Since it is based on supercritical fluid extraction coupled to gas chromatography-mass spectrometry, it minimizes the analysis time and significantly enhances sensitivity, which makes it suitable for trace-level compounds, which are constituents of SOA. One of the key features of this method is the in situ derivatisation step: an online silylation allowing the measurement of highly polar, polyfunctional compounds, which is a prerequisite for the elucidation of chemical mechanisms. This paper presents the development of this analytical method and highlights its ability to address this major atmospheric issue through the analysis of SOA formed from the ozonolysis of a biogenic hydrocarbon (sabinene). Ozonolysis of sabinene was performed in a 6 m3 Teflon chamber. The aerosol components were derivatised in situ. More than thirty products, such as sabinaketone, sabinic acid and other multifunctional compounds including dicarboxylic acids and oxoacids, were measured. Nine of them were identified and quantified. The sensitivity and the linearity (0.91<R<0.98) of the method were both good and detection limits ranged from 1.2 to 6.4 ng for the investigated compounds.
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Affiliation(s)
- L Chiappini
- Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Universités Paris, 7 et 12, 61 avenue du Général de Gaulle, 94010, Créteil, France.
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172
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Nash DG, Tolocka MP, Baer T. The uptake of O3 by myristic acid-oleic acid mixed particles: evidence for solid surface layers. Phys Chem Chem Phys 2006; 8:4468-75. [PMID: 17001415 DOI: 10.1039/b609855j] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The oleic acid ozonolysis in mixed oleic and myristic acid particles was studied in a flow tube reactor using single particle mass spectrometry. The change in reactivity was investigated as a function of the myristic acid concentration in these 2 micron particles. For pure oleic acid aerosol, the reactive ozone uptake coefficient, gamma, was found to be 3.4 (+/-0.3) x 10(-4) after taking secondary reactions into account. At the myristic acid crystallization point, where only 2.5% of the particle is in the solid phase, the uptake coefficient was reduced to 9.7 (+/-1.0) x 10(-5). This dramatic drop in the uptake coefficient is explained by the presence of a crystalline monolayer of myristic acid, through which ozone diffusion is reduced by several orders of magnitude, relative to liquid oleic acid. Scanning electron microscope images of the mixed particles confirm that the particle surface is crystalline when the myristic acid mole fraction exceeds 0.125. The findings of these experiments illustrate that particle morphology is important to understanding the reactivity of species in a mixed particle. The decay of myristic acid during the course of ozonolysis is explained in terms of a reaction with stabilized Criegee intermediates, which attack the acidic groups of the oleic and myristic acids with equal rate constants.
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Affiliation(s)
- David G Nash
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
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173
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Altieri KE, Carlton AG, Lim HJ, Turpin BJ, Seitzinger SP. Evidence for oligomer formation in clouds: reactions of isoprene oxidation products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:4956-60. [PMID: 16955892 DOI: 10.1021/es052170n] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) was used to investigate product formation in laboratory experiments designed to study secondary organic aerosol (SOA) formation in clouds. It has been proposed that water soluble aldehydes derived from aromatics and alkenes, including isoprene, oxidize further in cloud droplets forming organic acids and, upon droplet evaporation, SOA. Pyruvic acid is an important aqueous-phase intermediate. Time series samples from photochemical batch aqueous phase reactions of pyruvic acid and hydrogen peroxide were analyzed for product formation. In addition to the monomers predicted by the reaction scheme, products consistent with an oligomer system were found when pyruvic acid and OH radical were both present. No evidence of oligomer formation was found in a standard mix composed of pyruvic, glyoxylic, and oxalic acids prepared in the same matrix as the samples analyzed using the same instrument conditions. The distribution of high molecular weight products is consistent with oligomers composed of the mono-, oxo-, and di-carboxylic acids expected from the proposed reaction scheme.
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Affiliation(s)
- Katye E Altieri
- Institute of Marine and Coastal Sciences, Department of Environmental Sciences, Rutgers NOAA CMER Program, Rutgers, The State University of New Jersey, New Brunswick 08901-8521, USA.
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174
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Kido Soule MC, Hore DK, Jaramillo-Fellin DM, Richmond GL. Differing Adsorption Behavior of Environmentally Important Cyanophenol Isomers at the Air−Water Interface. J Phys Chem B 2006; 110:16575-83. [PMID: 16913792 DOI: 10.1021/jp061351o] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vibrational sum-frequency spectroscopy and surface tensiometry have been used to study the adsorption of m- and p-cyanophenol at the air-water interface. Spectra of the cyano (CN) group under different polarization schemes are utilized to determine its hydrogen bonding environment and orientation. For both isomers, it is found that the cyano group is hydrogen bonded at the interface but that the CN orientation is independent of surface density. The average CN tilt angle (theta(0)), however, is found to differ between the isomers, such that the CN group points down toward the aqueous phase for m-cyanophenol (theta(0) = 96-106 degrees ) but points up toward the vapor phase for the p-cyanophenol (theta(0) = 65-80 degrees ). In addition, this average tilt angle is distributed over a narrow range, sigma(0) < 10 degrees for the meta isomer and sigma(0) < 16 degrees for the para isomer.
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Affiliation(s)
- Melissa C Kido Soule
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
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175
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Abstract
Atmospheric carbon particles originate from natural sources and from human activity. The processes that lead to their formation are varied and include fossil fuel combustion, biomass burning, and mechanical stress and wear of carbonaceous materials. In this review, we examine recent work on the structure and composition of carbon aerosol particles, and we describe how they react with the atmospherically abundant gases ozone, oxygen, sulfur dioxide, nitric acid, and nitrogen oxides. The study of carbon particles in the laboratory has shown that chemical reactivity depends strongly on the type of carbon used and on experimental conditions such as temperature and humidity. The variability in the results demonstrates the difficulty in extrapolating laboratory results to atmospheric conditions and in explaining the role of carbon particles in processes such as global warming and environmental chemical cycling.
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Affiliation(s)
- Amanda M Nienow
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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176
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Takahama S, Davidson CI, Pandis SN. Semicontinuous measurements of organic carbon and acidity during the Pittsburgh Air Quality Study: implications for acid-catalyzed organic aerosol formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:2191-9. [PMID: 16646452 DOI: 10.1021/es050856+] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Laboratory evidence suggests that inorganic acid seed particles may increase secondary organic aerosol yields secondary organic aerosol (SOA) through heterogeneous chemistry. Additional laboratory studies, however, report that organic acidity generated in the same photochemical process by which SOA is formed may be sufficient to catalyze these heterogeneous reactions. Understanding the interaction between inorganic acidity and SOA mass is important when evaluating emission controls to meet PM2.5 regulations. We examine semicontinuous measurements of organic carbon (OC), elemental carbon (EC), and inorganic species from the Pittsburgh Air Quality Study to determine if we can detect coupling in the variations of inorganic acidity and OC. We were not able to detect significant enhancements of SOA production due to inorganic acidity in Western Pennsylvania most of the time, but its signal might have been lost in the noise. If we assume a causal relationship between inorganic acidity and OC, reductions in OC for Western Pennsylvania that might result from drastic reductions in inorganic acidity were estimated to be 2 +/- 4% by a regression technique, and an upper bound for this geographic area was estimated to be 5 +/- 8% based on calculations from laboratory measurements.
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Affiliation(s)
- S Takahama
- Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA
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177
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Tong C, Blanco M, Goddard WA, Seinfeld JH. Secondary organic aerosol formation by heterogeneous reactions of aldehydes and ketones: a quantum mechanical study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:2333-8. [PMID: 16646470 DOI: 10.1021/es0519785] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Experimental studies have provided convincing evidence that aerosol-phase heterogeneous chemical reactions (possibly acid-catalyzed) are involved to some extent in the formation of secondary organic aerosol (SOA). We present a stepwise procedure to determine physical properties such as heats of formation, standard entropies, Gibbs free energies of formation, and solvation energies from quantum mechanics (QM), for various short-chain aldehydes and ketones. We show that quantum mechanical gas-phase Gibbs free energies of formation compare reasonably well with the literature values with a root-mean-square (RMS) value of 1.83 kcal/mol for the selected compounds. These QM results are then used to determine the equilibrium constants (reported as log K) of aerosol-phase chemical reactions, including hydration reactions and aldol condensation for formaldehyde, acetaldehyde, acetone, butanal, hexanal, and glyoxal. Results are in qualitatively agreement with previous studies. In addition, the QM results for glyoxal reactions are consistent with experimental observations. To our knowledge, this is the first QM study that supports observations of atmospheric particle-phase reactions. Despite the significant uncertainties in the absolute values from the QM calculations, the results are potentially useful in determining the relative thermodynamic tendency for atmospheric aerosol-phase reactions.
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Affiliation(s)
- Chinghang Tong
- Department of Environmental Science and Engineering, Material and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, USA
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178
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Li Y, Demerjian KL, Williams LR, Worsnop DR, Kolb CE, Davidovits P. Heterogeneous Uptake of 8−2 Fluorotelomer Alcohol on Liquid Water and 1-Octanol Droplets. J Phys Chem A 2006; 110:6814-20. [PMID: 16722697 DOI: 10.1021/jp0563134] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The heterogeneous uptake of the 8-2 fluorotelomer alcohol, F(CF2)8CH2CH2OH, on liquid water surfaces over the temperature range 256-273 K and on 1-octanol surfaces over the temperature range 264-295 K has been investigated with a droplet train flow reactor. The uptake coefficient on water droplets is zero within the error of the measurement (+/-0.01) and is independent of droplet temperature. In contrast, significant uptake onto 1-octanol is observed. Measured uptake coefficients for 1-octanol showed a negative temperature dependence, varying from 0.034 +/- 0.005 (1sigma) at 295 K to 0.103 +/- 0.009 at 264 K. The measured uptake coefficients on 1-octanol were independent of gas-liquid contact time, for typical contact times varying between 3 and 15 ms, and independent of the 8-2 fluorotelomer alcohol gas-phase concentration, indicating that the uptake coefficients are equivalent to mass accommodation coefficients. The uptake coefficients on 1-octanol were also independent of relative humidity. These results show that the uptake of FTOHs on or into the aqueous component of cloud/fog droplets or aqueous aerosol particles is not likely to be an important atmospheric sink for these compounds. In these experiments, 1-octanol was used as a model compound for organic-containing atmospheric particles. The larger uptake coefficient measured for 1-octanol surfaces indicates that FTOH partitioning to organic-containing cloud/fog droplets and aerosol particles may be an atmospheric loss mechanism.
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Affiliation(s)
- Yongquan Li
- Atmospheric Sciences Research Center, State University of New York, 251 Fuller Road, Albany, New York 12203, USA
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179
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Docherty KS, Ziemann PJ. Reaction of Oleic Acid Particles with NO3 Radicals: Products, Mechanism, and Implications for Radical-Initiated Organic Aerosol Oxidation. J Phys Chem A 2006; 110:3567-77. [PMID: 16526637 DOI: 10.1021/jp0582383] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The heterogeneous reaction of liquid oleic acid aerosol particles with NO3 radicals in the presence of NO2, N2O5, and O2 was investigated in an environmental chamber using a combination of on-line and off-line mass spectrometric techniques. The results indicate that the major reaction products, which are all carboxylic acids, consist of hydroxy nitrates, carbonyl nitrates, dinitrates, hydroxydinitrates, and possibly more highly nitrated products. The key intermediate in the reaction is the nitrooxyalkylperoxy radical, which is formed by the addition of NO3 to the carbon-carbon double bond and subsequent addition of O2. The nitrooxyalkylperoxy radicals undergo self-reactions to form hydroxy nitrates and carbonyl nitrates, and may also react with NO2 to form nitrooxy peroxynitrates. The latter compounds are unstable and decompose to carbonyl nitrates and dinitrates. It is noteworthy that in this reaction nitrooxyalkoxy radicals appear not to be formed, as indicated by the absence of the expected products of decomposition or isomerization of these species. This is different from gas-phase alkene-NO3 reactions, in which a large fraction of the products are formed through these pathways. The results may indicate that, for liquid organic aerosol particles in low NOx environments, the major products of the radical-initiated oxidation (including by OH radicals) of unsaturated and saturated organic compounds will be substituted forms of the parent compound rather than smaller decomposition products. These compounds will remain in the particle and can potentially enhance particle hygroscopicity and the ability of particles to act as cloud condensation nuclei.
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Affiliation(s)
- Kenneth S Docherty
- Air Pollution Research Center, University of California, Riverside, California 92521, USA
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180
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Cai X, Griffin RJ. Secondary aerosol formation from the oxidation of biogenic hydrocarbons by chlorine atoms. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006857] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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181
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Lim YB, Ziemann PJ. Products and mechanism of secondary organic aerosol formation from reactions of n-alkanes with OH radicals in the presence of NOx. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:9229-36. [PMID: 16382947 DOI: 10.1021/es051447g] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Secondary organic aerosol (SOA) formation from reactions of n-alkanes with OH radicals in the presence of NOx was investigated in an environmental chamber using a thermal desorption particle beam mass spectrometer for particle analysis. SOA consisted of both first- and higher-generation products, all of which were nitrates. Major first-generation products were sigma-hydroxynitrates, while higher-generation products consisted of dinitrates, hydroxydinitrates, and substituted tetrahydrofurans containing nitrooxy, hydroxyl, and carbonyl groups. The substituted tetrahydrofurans are formed by a series of reactions in which sigma-hydroxycarbonyls isomerize to cyclic hemiacetals, which then dehydrate to form substituted dihydrofurans (unsaturated compounds) that quickly react with OH radicals to form lower volatility products. SOA yields ranged from approximately 0.5% for C8 to approximately 53% for C15, with a sharp increase from approximately 8% for C11 to approximately 50% for C13. This was probably due to an increase in the contribution of first-generation products, as well as other factors. For example, SOA formed from the C10 reaction contained no first-generation products, while for the C15 reaction SOA was approximately 40% first-generation and approximately 60% higher-generation products, respectively. First-generation sigma-hydroxycarbonyls are especially important in SOA formation, since their subsequent reactions can rapidly form low volatility compounds. In the atmosphere, substituted dihydrofurans created from sigma-hydroxycarbonyls will primarily react with O3 or NO3 radicals, thereby opening reaction pathways not normally accessible to saturated compounds.
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Affiliation(s)
- Yong Bin Lim
- Air Pollution Research Center, University of California, Riverside 92521, USA
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182
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Sato K. Chemical Compositions of Secondary Organic Aerosol from the Ozonolysis of Cyclohexene in the Absence of Seed Particles. CHEM LETT 2005. [DOI: 10.1246/cl.2005.1584] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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183
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Hastings WP, Koehler CA, Bailey EL, De Haan DO. Secondary organic aerosol formation by glyoxal hydration and oligomer formation: humidity effects and equilibrium shifts during analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:8728-35. [PMID: 16323769 DOI: 10.1021/es050446l] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Glyoxal is a significant atmospheric aldehyde formed from both anthropogenic aromatic compounds and biogenic isoprene emissions. The chemical behavior of glyoxal relevant to secondary organic aerosol (SOA) formation and analysis is examined in GC-MS, electrospray ionization (ESI)-MS, and particle chamber experiments. Glyoxal oligomers are shown to rapidly decompose to glyoxal in GC injection ports at temperatures > or = 120 degrees C. Glyoxal dihydrate monomer is dehydrated at temperatures > or = 140 degrees C during GC analysis but shows only oligomers (n < or = 7) upon ESI-MS analysis. Thus both of these analytical techniques will cause artifacts in speciation of glyoxal in SOA. In particle chamber experiments, glyoxal (at -0.1 Torr) condensed via particle-phase reactions when relative humidity levels exceeded a threshold of -26%. Both the threshold humidity and particle growth rates (-0.1 nm/min) are consistent with a recent study performed at glyoxal concentrations 4 orders of magnitude below those used here. This consistency suggests a mechanism where the surface water layer of solid-phase aerosol becomes saturated with glyoxal dihydrate monomer, triggering polymerization and the establishment of an organic phase.
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Affiliation(s)
- William P Hastings
- Chemistry Department, University of San Diego, 5998 Alcala Park, San Diego, California 92110, USA
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184
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Katrib Y, Biskos G, Buseck PR, Davidovits P, Jayne JT, Mochida M, Wise ME, Worsnop DR, Martin ST. Ozonolysis of Mixed Oleic-Acid/Stearic-Acid Particles: Reaction Kinetics and Chemical Morphology. J Phys Chem A 2005; 109:10910-9. [PMID: 16331935 DOI: 10.1021/jp054714d] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ozonolysis of mixed oleic-acid/stearic-acid (OL/SA) aerosol particles from 0/100 to 100/0 wt % composition is studied. The magnitude of the divergence of the particle beam inside an aerosol mass spectrometer shows that, in the concentration range 100/0 to 60/40, the mixed OL/SA particles are liquid prior to reaction. Upon ozonolysis, particles having compositions of 75/25 and 60/40 change shape, indicating that they have solidified during reaction. Transmission electron micrographs show that SA(s) forms needles. For particles having compositions of 75/25, 60/40, and greater SA content, the reaction kinetics exhibit an initial fast decay of OL for low O(3) exposure with no further loss of OL at higher O(3) exposures. For compositions from 50/50 to 10/90, the residual OL concentration remains at 28 +/- 2% of its initial value. The initial reactive uptake coefficient for O(3), as determined by OL loss, decreases linearly from 1.25 (+/-0.2) x 10(-3) to 0.60 (+/-0.15) x 10(-3) for composition changes of 100/0 to 60/40. At 50/50 composition, the uptake coefficient drops abruptly to 0.15 (+/-0.1) x 10(-3), and there are no further changes with increased SA content. These observations can be explained with a combination of three postulates: (1) Unreacted mixed particles remain as supersaturated liquids up to 60/40 composition, and the OL in this form rapidly reacts with O(3). (2) SA, as it solidifies, locks into its crystal structure a significant amount of OL, and this OL is completely inaccessible to O(3). (3) Accompanying crystallization, some stearic acid molecules connect as a filamentous network to form a semipermeable gel containing liquid OL but with a reduced uptake coefficient because of the decrease in molecular diffusivity in the gel. An individual particle of 50/50 to 90/10 is hypothesized as a combination of SA crystals having OL impurities (postulate 2) that are partially enveloped by an SA/OL gel (postulate 3) to explain (a) the abrupt drop in the uptake coefficient from 60/40 to 50/50 and (b) the residual OL content even after high ozone exposure. The results of this study, pointing out the important effects of particle phase, composition, and morphology on chemical reactivity, contribute to an improved understanding of the aging processes of atmospheric aerosol particles.
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Affiliation(s)
- Y Katrib
- Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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185
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Huff Hartz KE, Rosenørn T, Ferchak SR, Raymond TM, Bilde M, Donahue NM, Pandis SN. Cloud condensation nuclei activation of monoterpene and sesquiterpene secondary organic aerosol. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005754] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kara E. Huff Hartz
- Department of Chemical Engineering; Carnegie Mellon University; Pittsburgh Pennsylvania USA
| | - Thomas Rosenørn
- Department of Chemistry; University of Copenhagen; Copenhagen Denmark
| | - Shaun R. Ferchak
- Department of Chemical Engineering; Carnegie Mellon University; Pittsburgh Pennsylvania USA
| | - Timothy M. Raymond
- Department of Chemical Engineering; Bucknell University; Lewisburg Pennsylvania USA
| | - Merete Bilde
- Department of Chemistry; University of Copenhagen; Copenhagen Denmark
| | - Neil M. Donahue
- Department of Chemical Engineering; Carnegie Mellon University; Pittsburgh Pennsylvania USA
| | - Spyros N. Pandis
- Department of Chemical Engineering; Carnegie Mellon University; Pittsburgh Pennsylvania USA
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186
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Zhang Q, Alfarra MR, Worsnop DR, Allan JD, Coe H, Canagaratna MR, Jimenez JL. Deconvolution and quantification of hydrocarbon-like and oxygenated organic aerosols based on aerosol mass spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:4938-52. [PMID: 16053095 DOI: 10.1021/es048568l] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A new technique has been developed to deconvolve and quantify the mass concentrations of hydrocarbon-like and oxygenated organic aerosols (HOA and OOA) using highly time-resolved organic mass spectra obtained with an Aerodyne Aerosol Mass Spectrometer (AMS). This technique involves a series of multivariate linear regressions that use mass-to-charge ratios (ml/s) 57 (mostly C4H9+) and 44 (mostly CO2+)-the identified AMS mass spectral tracers for HOA and OOA, respectively-as the initial principal components. Two algorithms have been developed: algorithm 1 is based solely on m/z 44 and m/z 57, and algorithm 2 is an iterative procedure expanded from algorithm 1. This technique was applied to the AMS organic aerosol data acquired at the EPA Pittsburgh Supersite during September 2002. The reconstructed organic concentrations (= HOA + OOA) agree well with the measured values (r2 = 0.997, slope = 0.998), and the reconstructed organic data matrix (size = 3199 time steps x 300 m/z's) explains 99% of the variance in the measured time series. In addition, the extracted mass spectrum of HOA shows high similarity to those of diesel exhaust, lubricating oil, and freshly emitted traffic aerosols observed in urban areas, while the spectrum of OOA closely resembles those of aged organic aerosols sampled in rural areas and also shows similarity with the spectrum of fulvic acid- a humic-like substance that is ubiquitous in the environment and has previously been used as an analogue to represent polyacid components found in highly processed and oxidized atmospheric organic aerosols. There is evidence for the presence of a third component, although its contribution to the total organic signal appears to be small in this study. The most important result is that m/z 44 and m/z 57 are reliable AMS mass spectral "markers" that provide the "first guess" for algorithm 2 which allows the quantitative description of the organic aerosol concentration and mass spectra over a period of 16 days in a major urban area and allows the extraction of mass spectra of OOA and HOA that can be interpreted chemically. These findings indicate the potential of performing organic source apportionment on the basis of total particle mass, rather than on the basis of organic tracer compounds that contribute a small fraction of this mass.
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Affiliation(s)
- Qi Zhang
- Cooperative Institute for Research in Environmental Sciences (CIRES), Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, Colorado 80309-0216, USA
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187
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Sullivan RC, Prather KA. Recent Advances in Our Understanding of Atmospheric Chemistry and Climate Made Possible by On-Line Aerosol Analysis Instrumentation. Anal Chem 2005; 77:3861-85. [PMID: 15952760 DOI: 10.1021/ac050716i] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ryan C Sullivan
- Department of Chemistry & Biochemistry and Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0314, USA
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188
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Minofar B, Vrbka L, Mucha M, Jungwirth P, Yang X, Wang XB, Fu YJ, Wang LS. Interior and Interfacial Aqueous Solvation of Benzene Dicarboxylate Dianions and Their Methylated Analogues: A Combined Molecular Dynamics and Photoelectron Spectroscopy Study. J Phys Chem A 2005; 109:5042-9. [PMID: 16833856 DOI: 10.1021/jp050836u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aqueous solvation of benzene dicarboxylate dianions (BCD(2-)) was studied by means of photoelectron spectroscopy and molecular dynamics simulations. Photoelectron spectra of hydrated o- and p-BCD(2-) with up to 25 water molecules were obtained. An even-odd effect was observed for the p-BCD(2-) system as a result of the alternate solvation of the two negative charges. However, the high polarizability of the benzene ring makes the two carboxylate groups interact with each other in p-BCD(2-), suppressing the strength of this even-odd effect compared with the linear dicarboxylate dianions linked by an aliphatic chain. No even-odd effect was observed for the o-BCD(2-) system, because each solvent molecule can interact with the two carboxylate groups at the same time due to their proximity. For large solvated clusters, the spectral features of the solute decreased while the solvent features became dominant, suggesting that both o- and p-BCD(2-) are situated in the center of the solvated clusters. Molecular dynamics simulations with both nonpolarizable and polarizable force fields confirmed that all three isomers (o-, m-, and p-BCD(2-)) solvate in the aqueous bulk. However, upon methylation the hydrophobic forces overwhelm electrostatic interactions and, as a result, the calculations predict that the tetramethyl-o-BCD(2-) is located at the water surface with the carboxylate groups anchored in the liquid and the methylated benzene ring tilted away from the aqueous phase.
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Affiliation(s)
- Babak Minofar
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
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189
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Hung HM, Katrib Y, Martin ST. Products and Mechanisms of the Reaction of Oleic Acid with Ozone and Nitrate Radical. J Phys Chem A 2005; 109:4517-30. [PMID: 16833788 DOI: 10.1021/jp0500900] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The heterogeneous reactions of deposited, millimeter-sized oleic acid droplets with ozone and nitrate radicals are studied. Attenuated total reflectance infrared spectroscopy (ATR-IR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS) are used for product identification and quantification. The condensed-phase products of the ozonolysis of oleic acid droplets are 1-nonanal (30 +/- 3% carbon yield), 9-oxononanoic acid (14 +/- 2%), nonanoic acid (7 +/- 1%), octanoic acid (1 +/- 0.2%), azelaic acid (6 +/- 3%), and unidentified products. The infrared spectra show that a major fraction of the unidentified products contain an ester group. Additionally, the mass spectra show that at least some of the unidentified products have molecular weights greater than 1000 amu, which implicates a polymerization reaction. The observed steps of 172 amu (9-oxononanoic acid) and 188 amu (azelaic acid Criegee intermediate) in the mass spectra suggest that these species are the monomers in the condensed-phase polymerization reactions. 9-Oxononanoic acid is proposed to lengthen the molecular chain via secondary ozonide formation; the azelaic acid Criegee intermediate links molecules units via ester formation (specifically, alpha-acyloxyalkyl hydroperoxides). For the reaction of oleic acid with nitrate radicals, functional groups including -ONO(2), -O(2)NO(2), and -NO(2) are observed in the infrared spectra, and high molecular weight molecules are formed. Environmental scanning electron microscopy (ESEM) is employed to examine the hygroscopic properties of the oleic acid droplets before and after exposure to ozone or nitrate radical. After reaction, the droplets take up water at lower relative humidities compared to the unreacted droplets. The increased hygroscopic response may indicate that the oxidative aging of atmospheric organic aerosol particles has significant impact on radiative forcing.
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Affiliation(s)
- Hui-Ming Hung
- Division of Engineering and Applied Sciences, 29 Oxford Street, Pierce Hall, Room 122, Harvard University, Cambridge, Massachusetts 02138, USA
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190
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Griffin RJ. Development and initial evaluation of a dynamic species-resolved model for gas phase chemistry and size-resolved gas/particle partitioning associated with secondary organic aerosol formation. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005219] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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191
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192
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VanReken TM. Cloud condensation nucleus activation properties of biogenic secondary organic aerosol. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005465] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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193
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Gao S, Ng NL, Keywood M, Varutbangkul V, Bahreini R, Nenes A, He J, Yoo KY, Beauchamp JL, Hodyss RP, Flagan RC, Seinfeld JH. Particle phase acidity and oligomer formation in secondary organic aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:6582-6589. [PMID: 15669315 DOI: 10.1021/es049125k] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A series of controlled laboratory experiments are carried out in dual Teflon chambers to examine the presence of oligomers in secondary organic aerosols (SOA) from hydrocarbon ozonolysis as well as to explore the effect of particle phase acidity on SOA formation. In all seven hydrocarbon systems studied (i.e., alpha-pinene, cyclohexene, 1-methyl cyclopentene, cycloheptene, 1-methyl cyclohexene, cyclooctene, and terpinolene), oligomers with MW from 250 to 1600 are present in the SOA formed, both in the absence and presence of seed particles and regardless of the seed particle acidity. These oligomers are comparable to, and in some cases, exceed the low molecular weight species (MW < 250) in ion intensities in the ion trap mass spectra, suggesting they may comprise a substantial fraction of the total aerosol mass. It is possible that oligomers are widely present in atmospheric organic aerosols, formed through acid- or base-catalyzed heterogeneous reactions. In addition, as the seed particle acidity increases, larger oligomers are formed more abundantly in the SOA; consequently, the overall SOA yield also increases. This explicit effect of particle phase acidity on the composition and yield of SOA may have important climatic consequences and need to be considered in relevant models.
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Affiliation(s)
- Song Gao
- Department of Environmental Science, California Institute of Technology, MC 210-41, Pasadena, California 91125, USA
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194
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Gao S, Keywood M, Ng NL, Surratt J, Varutbangkul V, Bahreini R, Flagan RC, Seinfeld JH. Low-Molecular-Weight and Oligomeric Components in Secondary Organic Aerosol from the Ozonolysis of Cycloalkenes and α-Pinene. J Phys Chem A 2004. [DOI: 10.1021/jp047466e] [Citation(s) in RCA: 249] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Song Gao
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Melita Keywood
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Nga L. Ng
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Jason Surratt
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Varuntida Varutbangkul
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Roya Bahreini
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Richard C. Flagan
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - John H. Seinfeld
- Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
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Keywood MD, Varutbangkul V, Bahreini R, Flagan RC, Seinfeld JH. Secondary organic aerosol formation from the ozonolysis of cycloalkenes and related compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:4157-4164. [PMID: 15352455 DOI: 10.1021/es035363o] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The secondary organic aerosol (SOA) yields from the laboratory chamber ozonolysis of a series of cycloalkenes and related compounds are reported. The aim of this work is to investigate the effect of the structure of the hydrocarbon parent molecule on SOA formation for a homologous set of compounds. Aspects of the compound structures that are varied include the number of carbon atoms present in the cycloalkene ring (C5 to C8), the presence and location of methyl groups, and the presence of an exocyclic or endocyclic double bond. The specific compounds considered here are cyclopentene, cyclohexene, cycloheptene, cyclooctene, 1-methyl-1-cyclopentene, 1-methyl-1-cyclohexene, 1-methyl-1-cycloheptene, 3-methyl-1-cyclohexene, and methylenecyclohexane. The SOA yield is found to be a function of the number of carbons present in the cycloalkene ring, with an increasing number resulting in increased yield. The yield is enhanced by the presence of a methyl group located at a double-bonded site but reduced by the presence of a methyl group at a non-double-bonded site. The presence of an exocyclic double bond also leads to a reduced yield relative to that of the equivalent methylated cycloalkene. On the basis of these observations, the SOA yield for terpinolene relative to the other cyclic alkenes is qualitatively predicted, and this prediction compares well to measurements of the SOA yield from the ozonolysis of terpinolene. This work shows that relative SOA yields from ozonolysis of cyclic alkenes can be qualitatively predicted from properties of the parent hydrocarbons.
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Affiliation(s)
- M D Keywood
- Departments of Environmental Science and Engineering and of Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Wechsler AS, Auerbach BJ, Graham TC, Sabiston DC. Distribution of intramyocardial blood flow during pericardial tamponade. Correlation with microscopic anatomy and intrinsic myocardial contractility. J Thorac Cardiovasc Surg 1975. [PMID: 4423787 DOI: 10.1002/2015jd023697-t] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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