Final Report: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: UC-Riverside

EPA Grant Number: R826371C007
Subproject: 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: Shapiro, Paul
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 alpha-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 alpha-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 alpha-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 alpha-hydroxyhydroperoxides was obtained in the 1,2-dimethyl-1-cyclohexene or alpha-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 alpha-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 alpha-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
Other center views: All 49 publications 46 publications in selected types All 46 journal articles
Type Citation Sub Project Document Sources
Journal Article 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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  • Journal Article 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)
  • Abstract: American Chemical Society Abstract
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  • Journal Article 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. R826371 (Final)
    R826371C007 (Final)
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  • Journal Article 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)
  • Abstract: InterScience Abstract
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  • Journal Article 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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  • Journal Article 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 particles

    Progress and Final Reports:

    Original Abstract
  • 1998
  • 1999
  • 2000
  • 2001

  • Main 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