Grantee Research Project Results
Final Report: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: UC-Riverside
EPA Grant Number: R826371C007Subproject: this is subproject number 007 , established and managed by the Center Director under grant R826371
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States
Center Director: Seinfeld, John
Title: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: UC-Riverside
Investigators: Atkinson, Roger , Arey, Janet
Institution: University of California - Riverside
EPA Project Officer: Hahn, Intaek
Project Period: April 15, 1998 through April 14, 2003
RFA: Special Opportunity in Tropospheric Ozone (1997) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Objective:
This is one of the projects conducted by the Research Consortium. The main objectives of this research project were to select and target areas of uncertainty in the gas-phase atmospheric chemistry of organic species critical to understanding the formation of ozone and fine particles in urban and regional areas, including the formation of multifunctional product species and the formation of secondary organic aerosol.
Summary/Accomplishments (Outputs/Outcomes):
Aromatic Chemistry. Aromatic compounds typically account for approximately
20 percent of the nonmethane organic compounds observed in ambient air in urban
areas. Therefore, accurate knowledge of the products and mechanisms of the
atmospheric reactions of aromatic species are critical inputs for air quality
models. To address questions regarding the product yields of OH radical-initiated
reactions of polycyclic aromatic hydrocarbons (PAHs) under realistic ambient
NO2 concentrations, products of the gas-phase reactions of the OH radical with
p-xylene and 1,2,3- and 1,2,4-trimethylbenzene (the only important atmospheric
transformation process for these compounds) were measured by gas chromatography
in the presence of varying concentrations of NO2. The ring-cleavage products
2,3-butanedione (from 1,2,3- and 1,2,4-trimethylbenzene) and 3-hexene-2,5-dione
(from p-xylene and 1,2,4-trimethylbenzene), which were shown to be primary
products, exhibited a dependence of their formation yields on the NO2 concentration,
with higher yields from the reactions of the OH-aromatic adducts with O2 than
from their reactions with NO2. Our product yields indicated that under atmospheric
conditions, approximately 65-75 percent of the reaction products were accounted
for from the p-xylene and 1,2,3- and 1,2,4-trimethylbenzene reactions, assuming
that -dicarbonyls and unsaturated 1,4-dicarbonyls were coproducts formed in
identical yield.
We then investigated the products formed from the gas-phase reaction of OH radicals with 3-hexene-2,5-dione in the presence of NO at room temperature and atmospheric pressure of air using in situ atmospheric pressure ionization tandem mass spectrometry (API-MS). Products of molecular weight 102 and 191 were identified and from consideration of the potential reactions, these were attributed to CH3C(O)CH(OH)CHO and CH3C(O)CH(OH)CH(ONO2)C(O)CH3, respectively. Our product data indicated that the intermediate CH3C(O)CH(OH)CH(O·)C(O)CH3 alkoxy radical dominantly decomposed to CH3C(O)CH(OH)CHO plus CH3C·O, rather than decomposing to CH3C(O)CHO plus CH3C(O)C·HOH (and ultimately forming two molecules of methylglyoxal). These results were consistent with a previous study from this laboratory showing that methylglyoxal is not formed to any significant extent from this reaction.
Acenaphthene and acenaphthylene are PAHs emitted into the atmosphere from a variety of incomplete combustion sources such as diesel exhaust. Both PAHs were present in the gas phase under typical atmospheric conditions and therefore could undergo atmospheric gas-phase reactions with the OH radical and for acenaphthylene with ozone. Using a relative rate method, rate constants were measured at 296 ± 2 K for the OH radical reactions with acenaphthene and acenaphthylene. These rate constants (in units of 10-11 cm3 molecule-1 s-1) were 8.0 ± 0.4 and 12.4 ± 0.7, respectively; for the O3 reaction with acenaphthylene, the rate constant was (1.6 ± 0.1) x 10-16 cm3 molecule-1 s-1. The products of the gas-phase reactions of acenaphthene and acenaphthylene and their fully deuterated analogs were investigated using in situ API-MS and combined gas chromatography-mass spectrometry (GC-MS). The major products identified from the OH radical-initiated reaction of acenaphthene and acenaphthylene were a 10-carbon ring-opened product and a dialdehyde, respectively. The major product observed from the API-MS analysis of the O3 reaction with acenaphthylene was a secondary ozonide, which was not observed by GC-MS. Aerosol formation following the OH radical-initiated reaction of acenaphthene and acenaphthylene was not significant, being less than 1 percent in each case, while aerosol formation from the reaction of O3 with acenaphthylene accounted for approximately 13 percent of the product mass balance.
Ozone-Alkene Chemistry. The gas-phase reactions of O3 with 1-octene, trans-7-tetradecene,
1,2-dimethyl-1-cyclohexene and -pinene were studied in the presence of an
OH radical scavenger, primarily using in situ API-MS, to investigate the products
formed from the reactions of the thermalized Criegee intermediates in the presence
of water vapor and 2-butanol (1-octene and trans-7-tetradecene form the same
Criegee intermediate). With H3O+(H2O)n as the reagent ions, ion peaks at 149
u ([M+H]+) were observed in the API-MS analyses of the 1-octene and trans-7-tetradecene
reactions, which showed a neutral loss of 34 u (H2O2) and were attributed to
the
-hydroxyhydroperoxide CH3(CH2)5CH(OH)OOH, which must therefore have a
lifetime with respect to decomposition of tens of minutes or more. No evidence
for the presence of
-hydroxyhydroperoxides was obtained in the 1,2-dimethyl-1-cyclohexene
or
-pinene reactions, although the smaller yields of thermalized Criegee intermediates
in these reactions makes observation of a-hydroxyhydroperoxides from these
reactions less likely than from the 1-octene and trans-7-tetradecene reactions.
Quantifications of 2,7-octanedione from the 1,2-dimethyl-1-cyclohexene reactions
and of pinonaldehyde from the a-pinene reactions were made by gas chromatographic
analyses during reactions with cyclohexane or 2-butanol as the OH radical scavenger.
The measured yields of 2,7-octanedione from 1,2-dimethyl-1-cyclohexene and
of pinonaldehyde from
-pinene were 0.110 ± 0.020 and 0.164 ± 0.029,
respectively, and were independent of the OH radical scavenger used. Our data
suggested that mono-alkyl-substituted Criegee intermediates, RCHOO, form
-hydroxyhydroperoxides,
which have lifetimes with respect to decomposition of tens of minutes or more
and may therefore play a role in the formation of secondary organic aerosol
from the O3 reactions with alkenes and other organics containing >C=C< bonds.
Atmospheric Chemistry of Selected Oxygenated Products of Alkenes and Alkanes. A number of diols were used as solvents. Diols are formed in the atmosphere from the OH radical-initiated reactions of alkenes at sufficiently low NO concentrations. Organic peroxy + organic peroxy radical reactions were significant. Rate constants were measured at room temperature for the gas-phase reactions of OH radicals with 1,2-butanediol, 2,3-butanediol, 1,3-butanediol and 2-methyl-2,4-pentanediol, leading to estimated lifetimes of these diols of 4-6 hours. Gas chromatographic analyses showed the formation of hydroxycarbonyls in large yield. However, the hydroxyaldehydes expected to be formed were not observed because these compounds do not elute from gas chromatographic columns unless derivatized.
4,5-Dihydro-2-methylfuran (DHMF) formed from cyclization of 5-hydroxy-2-pentanone, an important gas-phase photooxidation product of n-pentane and a representative 1,4-hydroxycarbonyl. At very low (<< 1 percent) relative humidity, a lifetime of approximately 1.1 hour was obtained for the transformation of 5-hydroxy-2-pentanone to DHMF. Rate constants and products of the gas-phase reactions of DHMF with OH radicals, NO3 radicals, and O3 have been determined at room temperature, resulting in estimated tropospheric lifetimes of 1.3 hours, 24 seconds, and 7 minutes for the OH radical, NO3 radical, and O3 reactions, respectively. The major product observed from the OH radical-initiated reaction was CH3C(O)OCH2CH2CHO in 74 ± 19 percent yield, and CH3C(O)OCH2CH2CHO also was observed from the NO3 radical and O3 reactions, with measured yields of 5.4-12 percent and 23 percent, respectively.
Journal Articles on this Report : 6 Displayed | Download in RIS Format
| Other subproject views: | All 6 publications | 6 publications in selected types | All 6 journal articles |
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| Other center views: | All 47 publications | 44 publications in selected types | All 44 journal articles |
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Baker J, Aschmann SM, Arey J, Atkinson R. Reactions of stabilized criegee intermediates from the gas-phase reactions of O3 with selected alkenes. International Journal of Chemical Kinetics 2002;34(2):73-85. |
R826371 (Final) R826371C007 (Final) |
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Bethel HL, Atkinson R, Arey J. Products of the gas-phase reactions of OH radicals with p-xylene and 1,2,3- and 1,2,4-trimethylbenzene: effect of NO2 concentration. Journal of Physical Chemistry A 2000;104(39):8922-8929. |
R826371C007 (Final) R825252 (1998) R825252 (1999) R825252 (2000) R825252 (Final) |
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Bethel HL, Arey J, Atkinson R. Products of the OH radical-initiated reaction of 3-hexene-2,5-dione. Environmental Science & Technology 2001;35(22):4477-4480. |
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Bethel HL, Atkinson R, Arey J. Kinetics and products of the reactions of selected diols with the OH radical. International Journal of Chemical Kinetics 2001;33(5):310-316. |
R826371C007 (Final) R825252 (1998) R825252 (1999) R825252 (2000) R825252 (Final) |
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Martin P, Tuazon EC, Aschmann SM, Arey J, Atkinson R. Formation and atmospheric reactions of 4,5-dihydro-2-methylfuran. Journal of Physical Chemistry A 2002;106(47):11492-11501. |
R826371 (Final) R826371C007 (Final) |
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Reisen F, Arey J. Reactions of hydroxyl radicals and ozone with acenaphthene and acenaphthylene. Environmental Science & Technology 2002;36(20):4302-4311. |
R826371 (Final) R826371C007 (Final) |
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Supplemental Keywords:
air quality modeling, ambient air, particulate, ozone, environmental chemistry, California, CA, Northeastern United States., RFA, Scientific Discipline, Air, particulate matter, Environmental Chemistry, Analytical Chemistry, tropospheric ozone, Atmospheric Sciences, aerosol formation, atmospheric particulate matter, fine particles, airborne particulate matter, fine particulates, ozone, gas phase atmospheric chemistry, air sampling, air pollution models, air quality model, chemical composition, atmospheric aerosol particles, aersol particles, California, atmospheric chemistry, ambient aerosol particlesProgress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R826371 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R826371C001 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Cal Tech, UC-Riverside, UC-San Diego, UC-Davis Report
R826371C002 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Cal Tech, Carnegie Mellon, Georgia Institute, NJIT, Oregon Institute, UC-Irvine, UC-Riverside Report
R826371C003 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Cal Tech Report
R826371C004 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: California - Irvine Report
R826371C005 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Carnegie Mellon Report
R826371C006 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Carnegie Mellon Report
R826371C007 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: UC-Riverside
R826371C008 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Oregon Health and Science Report
R826371C009 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: NJIT Report
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.