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Shahi H, Reiisi S, Sadeghiani M, Mahsa M, Bahreini R, Moghni M, Damavandi M, Fatollahi F, Shahverdi E, Ramezani G, Shirzad H. Prevalence of cagA and babA2 genes in Helicobacter Pylori strains Isolated from Iranian gastrointestinal disorder patients and their gas-tritis classification. ACTA ACUST UNITED AC 2014. [DOI: 10.15412/j.jbtw.01031201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Bahreini R, Middlebrook AM, Brock CA, de Gouw JA, McKeen SA, Williams LR, Daumit KE, Lambe AT, Massoli P, Canagaratna MR, Ahmadov R, Carrasquillo AJ, Cross ES, Ervens B, Holloway JS, Hunter JF, Onasch TB, Pollack IB, Roberts JM, Ryerson TB, Warneke C, Davidovits P, Worsnop DR, Kroll JH. Mass spectral analysis of organic aerosol formed downwind of the Deepwater Horizon oil spill: field studies and laboratory confirmations. Environ Sci Technol 2012; 46:8025-8034. [PMID: 22788666 DOI: 10.1021/es301691k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In June 2010, the NOAA WP-3D aircraft conducted two survey flights around the Deepwater Horizon (DWH) oil spill. The Gulf oil spill resulted in an isolated source of secondary organic aerosol (SOA) precursors in a relatively clean environment. Measurements of aerosol composition and volatile organic species (VOCs) indicated formation of SOA from intermediate-volatility organic compounds (IVOCs) downwind of the oil spill (Science2011, 331, doi 10.1126/science.1200320). In an effort to better understand formation of SOA in this environment, we present mass spectral characteristics of SOA in the Gulf and of SOA formed in the laboratory from evaporated light crude oil. Compared to urban primary organic aerosol, high-mass-resolution analysis of the background-subtracted SOA spectra in the Gulf (for short, "Gulf SOA") showed higher contribution of C(x)H(y)O(+) relative to C(x)H(y)(+) fragments at the same nominal mass. In each transect downwind of the DWH spill site, a gradient in the degree of oxidation of the Gulf SOA was observed: more oxidized SOA (oxygen/carbon = O/C ∼0.4) was observed in the area impacted by fresher oil; less oxidized SOA (O/C ∼0.3), with contribution from fragments with a hydrocarbon backbone, was found in a broader region of more-aged surface oil. Furthermore, in the plumes originating from the more-aged oil, contribution of oxygenated fragments to SOA decreased with downwind distance. Despite differences between experimental conditions in the laboratory and the ambient environment, mass spectra of SOA formed from gas-phase oxidation of crude oil by OH radicals in a smog chamber and a flow tube reactor strongly resembled the mass spectra of Gulf SOA (r(2) > 0.94). Processes that led to the observed Gulf SOA characteristics are also likely to occur in polluted regions where VOCs and IVOCs are coemitted.
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Affiliation(s)
- R Bahreini
- Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, Colorado, USA.
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Moore RH, Cerully K, Bahreini R, Brock CA, Middlebrook AM, Nenes A. Hygroscopicity and composition of California CCN during summer 2010. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd017352] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ahmadov R, McKeen SA, Robinson AL, Bahreini R, Middlebrook AM, de Gouw JA, Meagher J, Hsie EY, Edgerton E, Shaw S, Trainer M. A volatility basis set model for summertime secondary organic aerosols over the eastern United States in 2006. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016831] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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de Gouw JA, Middlebrook AM, Warneke C, Ahmadov R, Atlas EL, Bahreini R, Blake DR, Brock CA, Brioude J, Fahey DW, Fehsenfeld FC, Holloway JS, Le Henaff M, Lueb RA, McKeen SA, Meagher JF, Murphy DM, Paris C, Parrish DD, Perring AE, Pollack IB, Ravishankara AR, Robinson AL, Ryerson TB, Schwarz JP, Spackman JR, Srinivasan A, Watts LA. Organic aerosol formation downwind from the Deepwater Horizon oil spill. Science 2011; 331:1295-9. [PMID: 21393539 DOI: 10.1126/science.1200320] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A large fraction of atmospheric aerosols are derived from organic compounds with various volatilities. A National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft made airborne measurements of the gaseous and aerosol composition of air over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico that occurred from April to August 2010. A narrow plume of hydrocarbons was observed downwind of DWH that is attributed to the evaporation of fresh oil on the sea surface. A much wider plume with high concentrations of organic aerosol (>25 micrograms per cubic meter) was attributed to the formation of secondary organic aerosol (SOA) from unmeasured, less volatile hydrocarbons that were emitted from a wider area around DWH. These observations provide direct and compelling evidence for the importance of formation of SOA from less volatile hydrocarbons.
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Affiliation(s)
- J A de Gouw
- Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA.
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Nowak JB, Neuman JA, Bahreini R, Brock CA, Middlebrook AM, Wollny AG, Holloway JS, Peischl J, Ryerson TB, Fehsenfeld FC. Airborne observations of ammonia and ammonium nitrate formation over Houston, Texas. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jd014195] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bahreini R, Ervens B, Middlebrook AM, Warneke C, de Gouw JA, DeCarlo PF, Jimenez JL, Brock CA, Neuman JA, Ryerson TB, Stark H, Atlas E, Brioude J, Fried A, Holloway JS, Peischl J, Richter D, Walega J, Weibring P, Wollny AG, Fehsenfeld FC. Organic aerosol formation in urban and industrial plumes near Houston and Dallas, Texas. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011493] [Citation(s) in RCA: 198] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Neuman JA, Nowak JB, Zheng W, Flocke F, Ryerson TB, Trainer M, Holloway JS, Parrish DD, Frost GJ, Peischl J, Atlas EL, Bahreini R, Wollny AG, Fehsenfeld FC. Relationship between photochemical ozone production and NOxoxidation in Houston, Texas. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011688] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bahreini R, Keywood MD, Ng NL, Varutbangkul V, Gao S, Flagan RC, Seinfeld JH, Worsnop DR, Jimenez JL. Measurements of secondary organic aerosol from oxidation of cycloalkenes, terpenes, and m-xylene using an Aerodyne aerosol mass spectrometer. Environ Sci Technol 2005; 39:5674-88. [PMID: 16124302 DOI: 10.1021/es048061a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The Aerodyne aerosol mass spectrometer (AMS) was used to characterize physical and chemical properties of secondary organic aerosol (SOA) formed during ozonolysis of cycloalkenes and biogenic hydrocarbons and photo-oxidation of m-xylene. Comparison of mass and volume distributions from the AMS and differential mobility analyzers yielded estimates of "effective" density of the SOA in the range of 0.64-1.45 g/cm3, depending on the particular system. Increased contribution of the fragment at m/z 44, C02+ ion fragment of oxygenated organics, and higher "delta" values, based on ion series analysis of the mass spectra, in nucleation experiments of cycloalkenes suggest greater contribution of more oxygenated molecules to the SOA as compared to those formed under seeded experiments. Dominant negative "delta" values of SOA formed during ozonolysis of biogenics indicates the presence of terpene derivative structures or cyclic or unsaturated oxygenated compounds in the SOA. Evidence of acid-catalyzed heterogeneous chemistry, characterized by greater contribution of higher molecular weight fragments to the SOA and corresponding changes in "delta" patterns, is observed in the ozonolysis of alpha-pinene. Mass spectra of SOA formed during photooxidation of m-xylene exhibit features consistent with the presence of furandione compounds and nitro organics. This study demonstrates that mixtures of SOA compounds produced from similar precursors result in broadly similar AMS mass spectra. Thus, fragmentation patterns observed for biogenic versus anthropogenic SOA may be useful in determining the sources of ambient SOA.
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Affiliation(s)
- R Bahreini
- Department of Environmental Science and Engineering, California Institute of Technology, Mail Code 210-41, 1200 East California Boulevard, Pasadena, California 91125, USA
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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. Environ Sci Technol 2004; 38:4157-4164. [PMID: 15352455 DOI: 10.1021/es035363o] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Conant WC, VanReken TM, Rissman TA, Varutbangkul V, Jonsson HH, Nenes A, Jimenez JL, Delia AE, Bahreini R, Roberts GC, Flagan RC, Seinfeld JH. Aerosol-cloud drop concentration closure in warm cumulus. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd004324] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- W. C. Conant
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
| | - T. M. VanReken
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - T. A. Rissman
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - V. Varutbangkul
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - H. H. Jonsson
- Center for Interdisciplinary Remotely-Piloted Aircraft Studies; Naval Postgraduate School; Monterey California USA
| | - A. Nenes
- Schools of Earth and Atmospheric Sciences and Chemical and Biomolecular Engineering; Georgia Institute of Technology; Atlanta Georgia USA
| | - J. L. Jimenez
- Department of Chemistry and Biochemistry, Cooperative Institute for Research in Environmental Sciences; University of Colorado; Boulder Colorado USA
| | - A. E. Delia
- Program in Atmospheric and Oceanic Sciences; University of Colorado; Boulder Colorado USA
| | - R. Bahreini
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
| | - G. C. Roberts
- Center for Atmospheric Sciences, Scripps Institution of Oceanography; University of California, San Diego; La Jolla California USA
| | - R. C. Flagan
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
| | - J. H. Seinfeld
- Department of Environmental Science and Engineering; California Institute of Technology; Pasadena California USA
- Department of Chemical Engineering; California Institute of Technology; Pasadena California USA
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Keywood MD, Kroll JH, Varutbangkul V, Bahreini R, Flagan RC, Seinfeld JH. Secondary organic aerosol formation from cyclohexene ozonolysis: effect of OH scavenger and the role of radical chemistry. Environ Sci Technol 2004; 38:3343-3350. [PMID: 15260334 DOI: 10.1021/es049725j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To isolate secondary organic aerosol (SOA) formation in ozone-alkene systems from the additional influence of hydroxyl (OH) radicals formed in the gas-phase ozone-alkene reaction, OH scavengers are employed. The detailed chemistry associated with three different scavengers (cyclohexane, 2-butanol, and CO) is studied in relation to the effects of the scavengers on observed SOA yields in the ozone-cyclohexene system. Our results confirm those of Docherty and Ziemann that the OH scavenger plays a role in SOA formation in alkene ozonolysis. The extent and direction of this influence are shown to be dependent on the specific alkene. The main influence of the scavenger arises from its independent production of HO2 radicals, with CO producing the most HO2, 2-butanol an intermediate amount, and cyclohexane the least. This work provides evidence for the central role of acylperoxy radicals in SOA formation from the ozonolysis of alkenes and generally underscores the importance of gas-phase radical chemistry beyond the initial ozone-alkene reaction.
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Affiliation(s)
- M D Keywood
- Department of Environmental Science, California Institute of Technology, Pasadena, California 91125, USA
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