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115 results on '"Edney, Edward O."'

2. Contribution of primary and secondary sources to organic aerosol and [PM.sub.2.5] at search network sites

Author

Kleindienst, Tadeusz E., Lewandowski, Michael, Offenberg, John H., Edney, Edward O., Jaoui, Mohammed, Zheng, Mei, Ding, Xiang, and Edgerton, Eric S.

Subjects
Aerosols -- Properties -- Environmental aspects, Organic compounds -- Environmental aspects, Carbon -- Environmental aspects, Environmental services industry, Environmental issues, Science and technology
Abstract

ABSTRACT Chemical tracer methods for determining contributions to primary organic aerosol (POA) are fairly well established, whereas similar techniques for secondary organic aerosol (SOA), inherently complicated by time-dependent atmospheric processes, [...]

Published
2010
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3. Investigation of a systematic offset in the measurement of organic carbon with a semicontinuous analyzer

Author

Offenberg, John H., Lewandowski, Michael, Edney, Edward O., Kleindienst, Tadeusz E., and Jaoui, Mohammed

Subjects
Aerosols -- Environmental aspects -- Usage -- Measurement, Semiconductor rectifiers -- Usage, Carbon compounds -- Measurement -- Environmental aspects -- Usage, Environmental services industry, Environmental issues, Science and technology
Abstract

ABSTRACT Organic carbon (OC) was measured semicontinuously in laboratory experiments of steady-state secondary organic aerosol formed by hydrocarbon + nitrogen oxide irradiations. Examination of the mass of carbon measured on [...]

Published
2007

7. Barrierless Reactions with Loose Transition States Govern the Yields and Lifetimes of Organic Nitrates Derived from Isoprene

Author

Piletic, Ivan R., Edney, Edward O., and Bartolotti, Libero J.

Abstract

The chemical reaction mechanism of NO addition to two β and δ isoprene hydroxy–peroxy radical isomers is examined in detail using density functional theory, coupled cluster methods, and the energy resolved master equation formalism to provide estimates of rate constants and organic nitrate yields. At the M06-2x/aug-cc-pVTZ level, the potential energy surfaces of NO reacting with β-(1,2)-HO-IsopOO•and δ-Z-(1,4)-HO-IsopOO•possess barrierless reactions that produce alkoxy radicals/NO2and organic nitrates. The nudged elastic band method was used to discover a loosely bound van der Waals (vdW) complex between NO2and the alkoxy radical that is present in both exit reaction channels. Semiempirical master equation calculations show that the β organic nitrate yield is 8.5 ± 3.7%. Additionally, a relatively low barrier to C–C bond scission was discovered in the β-vdW complex that leads to direct HONO formation in the gas phase with a yield of 3.1 ± 1.3%. The δ isomer produces a looser vdW complex with a smaller dissociation barrier and a larger isomerization barrier, giving a 2.4 ± 0.8% organic nitrate yield that is relatively pressure and temperature insensitive. By considering all of these pathways, the first-generation NOxrecycling efficiency from isoprene organic nitrates is estimated to be 21% and is expected to increase with decreasing NOxconcentration.

Published
2024
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10. Multigenerational Theoretical Study of Isoprene Peroxy Radical 1–5-Hydrogen Shift Reactions that Regenerate HOxRadicals and Produce Highly Oxidized Molecules

Author

Piletic, Ivan R., Howell, Richard, Bartolotti, Libero J., Kleindienst, Tadeusz E., Kaushik, Surender M., and Edney, Edward O.

Abstract

A computational protocol is employed to glean new insight into the kinetics of several 1,5-hydrogen atom (H) shift reactions subsequent to first- and second-generation OH/O2additions to isoprene. The M06-2X density functional was initially used with the Nudged Elastic Band (NEB) method to determine the potential energy surface of OH/O2addition reactions, the 1,5-H shift reactions, and the fragmentation exit channels. The Master Equation Solver for Multi-Energy Well Reactions (MESMER) was applied to determine the rate constants for OH addition and the 1,5-H shifts. M06-2X was capable of quantifying the rate constants of OH addition to the first and second double bonds of isoprene with deviations less than 17% from the experimentally determined values. However, M06-2X underestimated the 1,5-H shift rate constants of second-generation isoprene peroxy radicals. Consequently, MN15, ωB97X-D, and CBS-QB3 methods were employed to compute average barrier heights to first- and second-generation 1,5-H shifts. In the first generation, the rate constants of H abstraction by β-(1,2) and (4,3) isoprene hydroxy-peroxy radicals from the neighboring hydroxyl group are 1.1 × 10–3and 2.4 × 10–3s–1, respectively. These values are determined primarily by the barrier of the H shift reaction and, to a smaller albeit nonnegligible extent, by the stability of the resulting alkoxy radical and the exit barrier leading to C–C bond dissociation. In contrast, the average second-generation rate constant of 1,5-H shifts from H–R–OH sites to the peroxy radical is 1.8 × 10–1s–1, with tunneling playing the significant role of increasing this value relative to first-generation 1,5-H shifts. Under low NOxconditions, first-generation isoprene oxidation reactions may recycle HOxat levels ranging from 10 to 30% due in large part to 1,5-H shifts, with the recycling efficiency being sensitive to HO2concentrations and temperature. HOxrecycling is expected to increase to levels beyond 80% in second-generation reactions of oxidized isoprene species because of isoprene epoxydiol (IEPOX) formation and further 1,5-H shifts that are kinetically favorable.

Published
2018
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11. Epoxide Pathways Improve Model Predictions of Isoprene Markers and Reveal Key Role of Acidity in Aerosol Formation

Author

Pye, Havala O. T., primary, Pinder, Robert W., additional, Piletic, Ivan R., additional, Xie, Ying, additional, Capps, Shannon L., additional, Lin, Ying-Hsuan, additional, Surratt, Jason D., additional, Zhang, Zhenfa, additional, Gold, Avram, additional, Luecken, Deborah J., additional, Hutzell, William T., additional, Jaoui, Mohammed, additional, Offenberg, John H., additional, Kleindienst, Tadeusz E., additional, Lewandowski, Michael, additional, and Edney, Edward O., additional

Published
2013
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18. Organosulfate Formation in Biogenic Secondary Organic Aerosol

Author

Surratt, Jason D., primary, Gómez-González, Yadian, additional, Chan, Arthur W. H., additional, Vermeylen, Reinhilde, additional, Shahgholi, Mona, additional, Kleindienst, Tadeusz E., additional, Edney, Edward O., additional, Offenberg, John H., additional, Lewandowski, Michael, additional, Jaoui, Mohammed, additional, Maenhaut, Willy, additional, Claeys, Magda, additional, Flagan, Richard C., additional, and Seinfeld, John H., additional

Published
2008
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21. 3-methyl-1,2,3-butanetricarboxylic acid: An atmospheric tracer for terpene secondary organic aerosol

Author

Szmigielski, Rafal, primary, Surratt, Jason D., additional, Gómez-González, Yadian, additional, Van der Veken, Pieter, additional, Kourtchev, Ivan, additional, Vermeylen, Reinhilde, additional, Blockhuys, Frank, additional, Jaoui, Mohammed, additional, Kleindienst, Tadeusz E., additional, Lewandowski, Michael, additional, Offenberg, John H., additional, Edney, Edward O., additional, Seinfeld, John H., additional, Maenhaut, Willy, additional, and Claeys, Magda, additional

Published
2007
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23. Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/(−) electrospray ionization mass spectrometry

Author

Gómez‐González, Yadian, primary, Surratt, Jason D., additional, Cuyckens, Filip, additional, Szmigielski, Rafal, additional, Vermeylen, Reinhilde, additional, Jaoui, Mohammed, additional, Lewandowski, Michael, additional, Offenberg, John H., additional, Kleindienst, Tadeusz E., additional, Edney, Edward O., additional, Blockhuys, Frank, additional, Van Alsenoy, Christian, additional, Maenhaut, Willy, additional, and Claeys, Magda, additional

Published
2007
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28. Hydroxydicarboxylic Acids: Markers for Secondary Organic Aerosol from the Photooxidation of α-Pinene

Author

Claeys, Magda, primary, Szmigielski, Rafal, additional, Kourtchev, Ivan, additional, Van der Veken, Pieter, additional, Vermeylen, Reinhilde, additional, Maenhaut, Willy, additional, Jaoui, Mohammed, additional, Kleindienst, Tadeusz E., additional, Lewandowski, Michael, additional, Offenberg, John H., additional, and Edney, Edward O., additional

Published
2007
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30. Evidence for Organosulfates in Secondary Organic Aerosol

Author

Surratt, Jason D., primary, Kroll, Jesse H., additional, Kleindienst, Tadeusz E., additional, Edney, Edward O., additional, Claeys, Magda, additional, Sorooshian, Armin, additional, Ng, Nga L., additional, Offenberg, John H., additional, Lewandowski, Michael, additional, Jaoui, Mohammed, additional, Flagan, Richard C., additional, and Seinfeld, John H., additional

Published
2006
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36. Epoxide as a precursor to secondary organic aerosol formation from isoprene photooxidation in the presence of nitrogen oxides.

Author

Ying-Hsuan Lin, Haofei Zhang, Pye, Havala O. T., Zhenfa Zhang, Marth, Wendy J., Park, Sarah, Arashiro, Maiko, Tianqu Cui, Budisulistiorini, Sri Hapsari, Sexton, Kenneth G., Vizuete, William, Ying Xie, Luecken, Deborah J., Piletic, Ivan R., Edney, Edward O., Bartolotti, Libero J., Gold, Avram, and Surratt, Jason D.

Subjects
EPOXY compounds, AEROSOLS, ISOPRENE, PHOTOOXIDATION, NITROGEN oxides
Abstract

Isoprene is a substantial contributor to the global secondary organic aerosol (SOA) burden, with implications for public health and the climate system. The mechanism by which isoprene-derived SOA is formed and the influence of environmental conditions, however, remain unclear. We present evidence from controlled smog chamber experiments and field measurements that in the presence of high levels of nitrogen oxides (NOx = NO + NO2) typical of urban atmospheres, 2-methyloxirane-2-carboxylic acid (methacrylic acid epoxide, MAE) is a precursor to known isoprene-derived SOA tracers, and ultimately to SOA. We propose that MAE arises from decomposition of the OH adduct of methacryloylperoxynitrate (MPAN). This hypothesis is supported by the similarity of SOA constituents derived from MAE to those from photooxidation of isoprene, methacrolein, and MPAN under high-NOx conditions. Strong support is further derived from computational chemistry calculations and Community Multiscale Air Quality model simulations, yielding predictions consistent with field observations. Field measurements taken in Chapel Hill, North Carolina, considered along with the modeling results indicate the atmospheric significance and relevance of MAE chemistry across the United States, especially in urban areas heavily impacted by isoprene emissions. Identification of MAE implies a major role of atmospheric epoxides in forming SOA from isoprene photooxidation. Updating current atmospheric modeling frameworks with MAE chemistry could improve the way that SOA has been attributed to isoprene based on ambient tracer measurements, and lead to SOA parameterizations that better capture the dependency of yield on NOx. [ABSTRACT FROM AUTHOR]

Published
2013
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38. Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/( −) electrospray ionization mass spectrometry.

Author

Gómez-González, Yadian, Surratt, Jason D., Cuyckens, Filip, Szmigielski, Rafal, Vermeylen, Reinhilde, Jaoui, Mohammed, Lewandowski, Michael, Offenberg, John H., Kleindienst, Tadeusz E., Edney, Edward O., Blockhuys, Frank, Van Alsenoy, Christian, Maenhaut, Willy, and Claeys, Magda

Published
2008
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42. Secondary Organic Carbon and Aerosol Yields from the Irradiations of Isoprene and α-Pinene in the Presence of NOx and SO2.

Author

Kleindienst, Tadeusz E., Edney, Edward O., Lewandowski, Michael, Offenberg, John H., and Jaoui, Mohammed

Subjects
*IRRADIATION, *ISOPRENE, *HYDROCARBONS, *ORGANIC compounds, *AEROSOLS, *AIR pollution, *NITROGEN oxides, *NITRILE oxides, *TERPENES
Abstract

A laboratory study was carried out to investigate the secondary organic carbon (SOC) yields of α-pinene and isoprene in the presence of SO2, which produces acidic aerosol in the system. Experiments were based on irradiating each hydrocarbon (HC) with NOx in a 14.5 m³ smog chamber operated in the dynamic mode. The experimental design consisted of several multi-part experiments for each HC. In the first part of each experiment, an HC/NOx irradiation was conducted in the absence of SO2 and was followed by irradiations with the addition of SO2 in subsequent parts. Filter-based analyses for organic carbon were made using a thermal-optical approach either with an off-line instrument or in situ with an automated instrument. For isoprene in the absence of SO2, the SOC yield was approximately 0.001, a value consistent with earlier work from this laboratory. With the addition of up to 200 ppb SO2, the yield increased by a factor of 7. For α-pinene in the absence of SO2, the SOC yield of the irradiated mixture was found to average 0.096 from two experiments. With SO2 in the system, the SOC yield increased on average to 0.132. These results suggest that SO2, and by inference acidic aerosol, may play a role in increasing the yield of SOC from the photooxidation products of biogenic hydrocarbons or by the direct uptake of biogenic hydrocarbons onto acidic aerosol. [ABSTRACT FROM AUTHOR]

Published
2006
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45. Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/(−) electrospray ionization mass spectrometry

Author

Gómez‐González, Yadian, Surratt, Jason D., Cuyckens, Filip, Szmigielski, Rafal, Vermeylen, Reinhilde, Jaoui, Mohammed, Lewandowski, Michael, Offenberg, John H., Kleindienst, Tadeusz E., Edney, Edward O., Blockhuys, Frank, Van Alsenoy, Christian, Maenhaut, Willy, and Claeys, Magda

Abstract

In the present study, we have characterized in detail the MS2 and MS3 fragmentation behaviors, using electrospray ionization (ESI) in the negative ion mode, of previously identified sulfated isoprene secondary organic aerosol compounds, including 2‐methyltetrols, 2‐methylglyceric acid, 2‐methyltetrol mononitrate derivatives, glyoxal and methylglyoxal. A major fragmentation pathway for the deprotonated molecules of the sulfate esters of 2‐methyltetrols and 2‐methylglyceric acid and of the sulfate derivatives of glyoxal and methylglyoxal is the formation of the bisulfate [HSO4]− anion, while the deprotonated sulfate esters of 2‐methyltetrol mononitrate derivatives preferentially fragment through loss of nitric acid. Rational interpretation of MS2, MS3 and accurate mass data led to the structural characterization of unknown polar compounds in K‐puszta fine aerosol as organosulfate derivatives of photooxidation products of unsaturated fatty acids, i.e. 2‐hydroxy‐1,4‐butanedialdehyde, 4,5‐ and 2,3‐dihydroxypentanoic acids, and 2‐hydroxyglutaric acid, and of α‐pinene, i.e. 3‐hydroxyglutaric acid. The deprotonated molecules of the sulfated hydroxyacids, 2‐methylglyceric acid, 4,5‐ and 2,3‐dihydroxypentanoic acid, and 2‐ and 3‐hydroxyglutaric acids, showed in addition to the [HSO4]− ion (m/z 97) neutral losses of water, CO2 and/or SO3, features that are characteristic of humic‐like substances. The polar organosulfates characterized in the present work are of climatic relevance because they may contribute to the hydrophilic properties of fine ambient aerosol. In addition, these compounds probably serve as ambient tracer compounds for the occurrence of secondary organic aerosol formation under acidic conditions. Copyright © 2007 John Wiley & Sons, Ltd.

Published
2008
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