Grantee Research Project Results
Final Report: Chemistry of Secondary Organic Aerosol Formation from the Oxidation of Aromatic Hydrocarbons
EPA Grant Number: R833752Title: Chemistry of Secondary Organic Aerosol Formation from the Oxidation of Aromatic Hydrocarbons
Investigators: Ziemann, Paul J. , Arey, Janet , Atkinson, Roger
Institution: University of California - Riverside
EPA Project Officer: Chung, Serena
Project Period: October 1, 2007 through September 30, 2010 (Extended to March 31, 2012)
Project Amount: $514,464
RFA: Sources and Atmospheric Formation of Organic Particulate Matter (2007) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air
Objective:
In this project the overall goal was to develop a quantitative understanding of the kinetics, products, and mechanisms of secondary organic aerosol (SOA) formation from the photooxidation of aromatic hydrocarbons, and to provide this information to the scientific community in a form that can be readily incorporated into SOA modules used in air quality models for predicting atmospheric organic PM2.5 concentrations. These types of models are widely used to evaluate the potential effects of aerosols on global climate, air pollution and visibility, and human health, which are all important problems confronting society. Experimental studies were conducted in large Teflon environmental chambers under simulated atmospheric conditions and gas and particle chemical composition was analyzed using online and offline state-of-the-art methods including gas and liquid chromatography, spectrophotometry, and gas and particle mass spectrometry.
Summary/Accomplishments (Outputs/Outcomes):
1. Gas-Phase Studies
In year 1 of this program, environmental chamber experiments were carried out to identify and quantify dicarbonyl products formed from reactions of OH radicals with toluene, o-, m- and p-xylene and 1,2,3-, 1,2,4- and 1,3,5-trimethylbenzene. Gas-phase products were collected using denuders coated with XAD resin and O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) to derivatize carbonyl-containing products for GC/MS analysis. The 1,2-dicarbonyls glyoxal, methylglyoxal and biacetyl were observed, as were 8 of 9 possible unsaturated 1,4-dicarbonyl co-products. Compared to their potential co-product 1,2-dicarbonyls, unsaturated 1,4-diketones had similar formation yields, whereas all but one unsaturated 1,4-dialdehyde and keto-aldehyde had lower yields. Measured yields (%) were as follows (G = glyoxal, MG = methylglyoxal, BA = biacetyl, and UDC = unsaturated 1,4-dicarbonyls): toluene: G = 17, MG = 16, UDC = 3.5–10, 0.5–1.4 and 11-32; o-xylene: G = 7, MG = 34, BA = 20, UDC = 0.3–1, 9–26, and 10–29; m-xylene: G = 6, MG = 40, UDC = 0.7–2, 12–34 and 5–14; p-xylene: G = 32, MG = 17, UDC = 20–59 and 2–7; 1,2,3-trimethylbenzene: G = 2, MG = 15, BA = 42, UDC = 0.03–0.09, 2–5, and 9–26; 1,2,4-trimethylbenzene: G = 5, MG = 39, BA = 6, UDC = 2–7, 0.1–0.4, 0.3–0.9, 20–59, and 2–6; 1,3,5-trimethylbenzene: MG = 60, UDC = 5–14. The gloxal and methylglyoxal yields (and presumably also the unsaturated dicarbonyl yields) from toluene, the xylene isomers and 1,3,5-trimethylbenzene decreased with increasing NO2 concentration, but with no effect of NO2 concentration on the glyoxal and methylglyoxal yields from 1,2,3- and 1,2,4-trimethylbenzene. These results provide new product yields from aromatic reactions that can be used as inputs to atmospheric models.
In addition, the photolysis rate of 2-formylcinnamaldehyde was measured by monitoring its time dependent signal during the naphthalene-OH reaction using atmospheric pressure ionization mass spectrometry (API-MS). 2-Formylcinnamaldehyde is a major product of the OH radical-initiated reaction of naphthalene, the atmospherically most abundant polycyclic aromatic hydrocarbon, whose oxidation has been suggested as a possible source of SOA in urban atmospheres. Results were used with those from our earlier (1997) study to determine a 2-formylcinnamaldehyde formation yield of 56%. Combined with other previously observed and quantified products, we now can account for ~92% of naphthalene reaction products under conditions where the NO2 concentration is greater than ~60 ppbv.
In year 2 of this project, the formation yields of glyoxal were measured from the OH radical-initiated reactions of naphthalene, 1-methylnaphthalene, 1,4-dimethylnaphthalene, acenaphthene and acenaphthylene, using solid phase microextraction (SPME) fibers pre-coated with PFBHA for collection of glyoxal and GC-FID for analysis. In the presence of NOx, glyoxal was observed as a first-generation product from these PAHs, with yields of 5%, 3%, 2%, 10-15% and <2%, respectively, and with a yield from naphthalene in the absence of NOx of 3%. Second-generation formation was obvious from the 1-methylnaphthalene, 1,4-dimethylnaphthalene and acenaphthene reactions. Simultaneous measurements of phthaldialdehyde from naphthalene, of 2-acetylbenzaldehyde from 1-methylnaphthalene and of 1,2-diacetylbenzene from 1,4-dimethylnaphthelene suggest that these aromatic dicarbonyls are co-products to glyoxal. The formation yields of glyoxal and methylglyoxal were measured from the gas-phase OH radical-initiated reactions of toluene, o-, m- and p-xylene, and 1,2,3-, 1,2,4- and 1,3,5-trimethylbenzene as a function of the NO2 concentration [(0.1-4) ppm]. Glyoxal and methylglyoxal were collected onto SPME fibers pre-coated with PFBHA and analyzed as their oximes by GC-FID. The glyoxal and methylglyoxal yields generally decrease with increasing NO2 concentration. However, for formation of glyoxal from 1,2,3-trimethylbenzene and of glyoxal and methylglyoxal from 1,2,4-trimethylbenzene, the yields were independent of the NO2 concentration within the experimental errors. These data allow, by a very short extrapolation, glyoxal and methylglyoxal yields appropriate for atmospheric conditions.
In years 2 and 3 of this project, 2-formylcinnamaldehyde formation from OH + naphthalene was investigated in the absence of NOx (using O3 + alkene to generate OH radicals) and in the presence of NOx at 0.1 and 1 ppm NOx. SPME fibers were used for sample collection, and our data show that 2-formylcinnamaldehyde is formed in the absence (as well as in the presence) of NOx, indicating that the OH-naphthalene adduct + O2 reaction forms 2-formylcinnamaldehyde. Based on our previous 2-formylcinnamaldehyde yield at ppm levels of NO2, the 2-formylcinnamaldehyde yields at 0.1 ppm NOx and in the absence of NOx are ~37% and ~17%, respectively. In the absence of NO, RO2 + RO2 and RO2 + HO2 radical reactions will dominate and a lower yield of 2-formylcinnamaldehyde is expected if 2-formylcinnamaldehyde is formed from an alkoxy radical. However, another route to 2-formylcinnamaldehyde formation from the OH-naphthalene + O2 reaction has been proposed, involving isomerization of the OH-naphthalene-O2 radical to O-naphthalene-OOH followed by elimination of OH and formation of 2-formylcinnamaldehyde. Our data indicate that the 2-formylcinnamaldehyde formation yields from the OH-naphthalene adduct reactions with NO2 and O2 are 56% and 14%, respectively. We investigated the formation of unsaturated 1,4-dicarbonyls (and other products) from the OH radical-initiated reactions of furans (furan, 2- and 3-methylfuran, and 2,3- and 2,5-dimethylfuran), using PFBHA-coated denuders, gas chromatography and API-MS. These studies are valuable for understanding the chemistry of aromatic reactions because the unsaturated 1,4-dicarbonyls formed from these furans are the same as those formed from aromatics, but are formed in higher yields and with fewer co-products so they can be used more easily to investigate the subsequent kinetics and products of the 1,4-unsaturated dicarbonyl reactions. We find that furan forms HC(O)CH=CHCHO, 2-methylfuran forms CH3C(O)CH=CHCHO, 3-methylfuran forms HC(O)C(CH3)=CHCHO, 2,3-dimethylfuran forms CH3C(O)C(CH3)=CHCHO, and 2,5-dimethylfuran forms CH3C(O)CH=CHC(O)CH3, with formation yields in the presence of NO of 82 ± 9%, 31 ± 5%, 38 ± 2%, 8± 2%, and 24 ± 3%, respectively. The formation yield of CH3C(O)CH=CHC(O)CH3 (mainly the cis-isomer) from OH + 2,5-dimethylfuran in the absence of NO was also measured, and determined to be 34 ± 4%. API-MS analyses showed the formation of additional products from the all of the furans studied which are attributed to (taking furan as an example) HC(O)CH=CHCOOH and/or the isomeric hydroxylactone. In addition, for OH + 2,5-dimethylfuran API-MS analyses showed the formation of a product attributed to the keto-ester CH3C(O)OCH=CHC(O)CH3. Using API-MS to monitor the 1,4-unsaturated dicarbonyls, the concentration-time dependence of the 1,4-unsaturated dicarbonyls have been studied from the five furans available; the results indicate that in our chambers with blacklamp irradiation, removal of the unsaturated 1,4-dicarbonyls is dominated by reaction with OH radicals, with OH radical reaction rate constants of (6 ± 2) x 10-11 cm3 molecule-1 s-1, and showing no evidence of rapid photolysis or wall loss rate of the unsaturated 1,4-dicarbonyls.
We have investigated formation of cresols from the OH + m-xylene and OH + p-cymene reactions to assess the importance of dealkylation (e.g., OH + m-xylene → cresol + CH3). We see no evidence for cresol formation from either reaction (<1% of any cresol isomer from m-xylene and <2% of any cresol isomer from p-cymene). Formation of 4-methylacetophenone, a product expected after H-atom abstraction from the CH(CH3)2 group, was observed from p-cymene, and a yield of 14.8 ± 3.2% measured. Inclusion of other products arising after H-atom abstraction from the methyl and isopropyl substituent groups indicates that H-atom abstraction from these substituent groups accounts for 20 ± 4% of the overall OH radical reaction for p-cymene. The formation yields of dimethylnitronaphthalenes have been measured from the reactions of OH radicals with 1,7- and 2,7-dimethylnaphthalene (these are the dominant dimethylnitronaphthalenes during daytime in the atmosphere) as a function of NO2 concentration. The yield of 1,7-dimethylnitronaphthalenes from OH + 1,7-dimethylnaphthalene is ~0.25%, and that for 2,7-dimethylnitronaphthalenes from OH + 2,7-dimethylnaphthalene is ~0.07%, both with a dependence on the NO2 concentration similar to that for naphthalene.
During year 4 of this program, we investigated the behavior of PAHs and nitro-PAHs in ambient particles, collected on filters, exposed to O3, OH radicals in the presence of NOx, and NO3 radicals in the presence of N2O5 and NO2. This work has been conducted at UCR in collaboration with Prof. Staci Simonich of Oregon State University, and particulate matter from Riverside and other locations in the Los Angeles basin and from Beijing, China, have been exposed. Chemical and data analyses are still under way. However, for exposure to NO3 radicals in the presence of N2O5 and NO2, it appears to a first approximation that formation of nitro-PAHs occurs for freshly emitted particulate matter (e.g., collected in downtown Los Angeles during nighttime) while little or no change in PAHs or nitro-PAHs occurs for particulate matter that has been photochemically aged (e.g., particulate matter collected in Riverside). A more comprehensive picture will emerge after the chemical and data analyses are complete.
Dimethylnitronaphthalene (DMNN) formation yields from the reactions of 1,7- and 2,7-dimethylnaphthalene (DMN) with OH radicals were measured over the NO2 concentration range 0.04-1.4 ppm. The measured DMNN formation yields under conditions that the OH-DMN adducts reacted solely with NO2 were 0.252 ± 0.094% for Σ1,7-DMNNs and 0.010 ± 0.005% for Σ2,7-DMNNs. 1,7-DM-5-NN was the major isomer formed, with a limiting high-NO2 concentration yield of 0.212 ± 0.080% and with equal reactions of the adduct with NO2 and O2 occurring in air at 60 ± 39 ppbv of NO2 (similar to the corresponding value for the OH-naphthalene adduct reactions). The reactions of the OH-DMN adducts with NO2 must therefore result in products other than DMNNs. Although the yields of the DMNNs are low, ≤0.3%, the DMNN (and ethylnitronaphthalene) profiles from chamber experiments match well with those observed in polluted urban areas under conditions where OH radical-initiated chemistry is dominant.
Additionally, in year 4 we investigated the products formed from OH + cycloalkane reactions as a means to better understand the chemistry of cyclic radical intermediates. In particular, we investigated whether or not the cycloalkoxy radicals undergo isomerization (mass spectral peaks in the SOA from OH + cyclododecane and cyclopentadecane suggest the presence of products formed subsequent to cycloalkoxy radical isomerization). We investigated the products from cyclohexane, cycloheptane, cyclooctane and cyclodecane reactions using atmospheric pressure ionization mass spectrometry and gas chromatography. Formation yields of the cycloketones (formed from cycloalkoxy + O2 reactions) were 4.2% for cycloheptanone from cycloheptane, 0.85% for cyclooctanone from cyclooctane, and 4.9% for cyclodecanone from cyclodecane. The formation of cyclic hydroxyketones (expected products of the cycloalkoxy radical isomerization) were observed for the cycloheptane, cyclooctane and cyclodecane reactions, but not from cyclohexane. Analyses of products showed, in addition to the cycloketones and cyclic hydroxyketones, the presence of cycloalkyl nitrates, hydroxydicarbonyls, hydroxycarbonyl nitrates, and products attributed to carbonyl nitrates and/or cyclic hydroxynitrates. The observed formation of cyclic hydroxyketones from the cycloheptane, cyclooctane and cyclodecane reactions, with estimated molar yields of 46%, 28%, and 15%, respectively, indicates the occurrence of cycloalkoxy radical isomerization.
2. Secondary Organic Aerosol Studies
The approach to SOA studies has built on our growing understanding of gas-phase chemistry and has sought to determine the specific gas-phase reaction products and conditions that lead to SOA formation. The chemistry is complicated because products of OH radical-initiated reactions of aromatics are influenced by concentrations of NO, NO2, RO2• and HO2 radicals. NO2 can compete with O2 in reactions of the OH-aromatic adduct, NO can compete with isomerization of the aromatic hydroxyperoxy radical, and NO, NO2, RO2•, and HO2 radicals can all compete with each other in reactions with RO2• radicals. Furthermore, it appears that oligomers are a major component of SOA and the reactions that lead to their formation are complex and influenced by the specific mix of gas-phase products, RH, and acidity. In years 2 and 3 of this project, a large number of environmental chamber reactions were conducted to investigate the yields of SOA formed from OH radical-initiated reactions of m-xylene, 3-methylfuran, and 2-methylfuran under different NO, NO2, and RH regimes. It currently is known that a variety of products are formed from aromatic reactions. Two of those formed in the presence of NOx are aromatic products that include aldehydes and dimethyl phenols. Non-aromatic products include bicyclic peroxides, diunsaturated dicarbonyls and unsaturated epoxydicarbonyls formed by ring opening, and 1,2-dicarbonyls and their unsaturated 1,4-dicarbonyl co-products formed by ring opening followed by decomposition.
It has been thought that highly multifunctional, second-generation products formed by the reactions of the unsaturated 1,4-dicarbonyls with OH radicals might be significant contributors to SOA formation. To investigate this possibility, the yields of SOA formed from the reactions of m-xylene were compared with those formed from similar reactions of 3-methylfuran and 2-methylfuran, which form the unsaturated 1,4-dicarbonyls 2-methyl-2-butene-dial and 4-oxo-pentenal in higher yields than from the m-xylene reaction. SOA yields/reacted unsaturated 1,4-dicarbonyl were estimated from the measurements and it was observed that under all conditions the SOA yields from the m-xylene reactions were much larger (often by more than an order of magnitude) than could be explained by the products of unsaturated 1,4-dicarbonyl reactions. This indicates that the products formed from reactions of unsaturated 1,4-dicarbonyls were not by themselves responsible for SOA formation from m-xylene. This conclusion was supported by real-time and temperature-programmed thermal desorption particle mass spectra, which showed that the SOA formed from the m-xylene and methylfuran reactions had very different compositions. In year 4, measurements of UV-Vis spectra, elemental composition, functional groups, and mass spectra, followed by data interpretation that built on the results of the gas phase products analysis described above, showed that the SOA formed in the furan and methylfuran reactions with OH radicals is composed primarily of oligomeric esters formed by the particle phase reactions of the first generation unsaturated oxoacid and hydroxylactone products. This is one of the few studies to definitively identify oligomeric products in SOA (most are highly complex mixtures) and their precursors, and also demonstrates the potentially facile nature of ester forming reactions.
It often has been reported that SOA formation from the photooxidation of aromatics is much higher in the absence of NO (conditions indicative of the clean atmosphere), with the usual explanation being that under these conditions organic peroxides are formed that contribute significantly to SOA formation. This explanation has never been tested, so in year 3 we measured the mass of organic peroxides in SOA formed from OH-initiated reactions of toluene, m-xylene, p-xylene, 1,3,5-trimethylbenzene, and benzaldehyde in the presence and absence of NO using an iodometric-spectrophotometric method we developed previously. Results were quite consistent, with SOA mass fractions of organic peroxides of ~5–6% for reactions in the presence of NO and ~13–16% in the absence of NO. These results provide the first direct evidence that organic peroxides contribute significantly to SOA formation from aromatic oxidation, especially in the absence of NO, but that other components also are important.
One potential explanation for the other SOA components we considered was that methylglyoxal, aromatic aldehydes, or dimethyl phenols, which are not formed in the methylfuran reactions, or some unknown products, are important for SOA formation, either alone or through oligomer-forming reactions with the products of the unsaturated 1,4-dicarbonyl reactions. This possibility was explored by adding methyglyoxal, aromatic aldehydes, and phenols to a chamber containing the products of methylfuran reactions, but no additional SOA was formed. This result supports the conclusion that second-generation reaction products of unsaturated 1,4-dicarbonyls, as well as aromatic aldehydes, dimethyl phenols, and 1,2-dicarbonyls do not play a significant role in SOA formation from the oxidation or aromatic compounds in the presence of NOx in dry air. Furthermore, reactions of aromatics conducted under dry and humid (~50% RH) conditions produced similar particle mass spectra, indicating that humidity has little effect on SOA formation in these systems.
Having ruled out many of the known gas-phase reaction products as potential contributors to SOA formation, in year 4 additional chamber experiments were conducted with toluene, m-xylene (including a series using two types of deuterium labeled compounds), p-xylene, and 1,3,5-trimethylbenzene with OH radicals in the presence and absence of NOx in an attempt to identify the SOA products of aromatic oxidation. Distinctive patterns in the particle mass spectra and thermal desorption profiles of SOA provided strong evidence that most of the SOA consists of unsaturated epoxydicarbonyls, the second-generation products of the reactions of OH radicals with these compounds, which are expected to be mostly multifunctional carbonyls, hydroxycarbonyls, and hydroxycarbonyl nitrates, and also bicyclic peroxides and nitrophenols. The second-generation products of the reactions of OH radicals with diunsaturated dicarbonyls also appear to contribute, but these compounds are not expected to be present in the atmosphere where NO concentrations are lower. Whereas some of these compounds might exist in the particles as monomers, based on thermal desorption profiles it is more likely that all the compounds are present in the form and hemiacetals and (for low NOx conditions) peroxyhemiacetals, again demonstrating the important role of oligomers in SOA formation from aromatic oxidation reactions.
Conclusions:
The primary objectives of this project, which were to investigate the formation of gas-phase and aerosol products from the OH radical-initiated reactions of a variety of aromatic compounds and appropriate model alkenes and dienes, including the effects of humidity, particle acidity, ammonia, and organic mixtures, have been met. A significant amount of valuable new data on kinetics and product yields for these reactions has been obtained, and substantial new insight into the products of aromatic reactions that are (and are not) responsible for SOA formation achieved. As summarized in our review article (see Ziemann and Atkinson 2012 in publications list), reactions of monoaromatic compounds with OH radicals appear to proceed by a now reasonably well-established mechanism that involves both addition of OH radicals to the aromatic ring and H-atom abstraction from substituent groups. Using yields from the literature (including our measured values) for glyoxal, methylglyoxal and biacetyl formation at low NO2 concentration, under atmospheric conditions the formation of 1,2-dicarbonyls accounts for approximately 47%, 64%, 63%, 58%, 62%, 46%, and 58% of the overall products from the toluene, o-, m-, p-xylene, 1,2,3-, 1,2,4-, and 1,3,5-trimethylbenzene reactions, respectively. Products arising from the H-atom abstraction pathway and phenolic compounds formed after OH radical addition also are formed and increase the above numbers to approximately 72%, 76%, 79%, 80%, 54%, and 65% of the overall products from the toluene, o-, m-, p-xylene, 1,2,4-, and 1,3,5-trimethylbenzene reactions, respectively (no formation yields of H-atom abstraction products or of phenolic products have been measured to date from the OH + 1,2,3-trimethylbenzene reaction). The measured bicyclic nitrate yields for benzene, toluene, p-xylene and 1,3,5-trimethylbenzene are in the range 2–3%, which when combined with the other data indicate that reaction pathways leading to H-atom abstraction products, phenols, and 1,2-dicarbonyls, unsaturated 1,4-dicarbonyls, and associated bicyclic nitrates account for approximately 75%, 79%, 82%, 83%, 65% 57%, and 68% of products from the toluene, o-, m-, p-xylene, 1,2,3-, 1,2,4-, and 1,3,5-trimethylbenzene reactions, respectively, with the reaction pathway proceeding through the bicyclic radical intermediate accounting for ~60% of the total OH addition pathways. The remaining ~20–40% of the reaction products are presumably unsaturated epoxydicarbonyls which have been identified but not as well quantified as the other products. The unsaturated epoxydicarbonyls, the second-generation products of the reactions of OH radicals with these compounds and with diunsaturated dicarbonyls, which are mostly multifunctional carbonyls, hydroxycarbonyls, and hydroxycarbonyl nitrates, and also bicyclic peroxides and nitrophenols appear to explain reasonably well the SOA mass spectra, yields, and other experimental results obtained here on SOA formed from reactions of aromatic compounds. Whereas some of these compounds might exist in the particles as monomers, it is more likely that all the compounds are present in the form of hemiacetals and for low NOx conditions also peroxyhemiacetals, demonstrating the key role of oligomers in SOA formation from aromatic oxidation reactions.
For the purposes of atmospheric modeling of SOA formation from the reactions of aromatic compounds it should be possible to simulate with some confidence much of the gas-phase chemistry leading to first- and second-generation products based on kinetics and product yield data that now are available or can be estimated from the literature. Yield data on unsaturated epoxydicarbonyls are still lacking, however, and there are still challenges that need to be met to accurately model gas-particle partitioning and oligomer-forming reactions. For the hemiacetals and peroxyhemiacetals that appear to be formed from the products of aromatics oxidation, a starting point is the summary of literature data on these reactions provided in the Ziemann and Atkinson 2012 review article. In addition to filling some gaps in knowledge of gas-phase chemistry (which should consider more carefully the potential effects of wall losses of volatile and semivolatile organic products to chamber walls, which may be especially important in aromatic reactions), future studies need to investigate oligomer-forming reactions from a larger variety of multifunctional compounds than has been done thus far, and also the role of aqueous-phase oxidation of small water-soluble reaction products such as glyoxal and methylglyoxal.
Journal Articles on this Report : 16 Displayed | Download in RIS Format
Other project views: | All 34 publications | 16 publications in selected types | All 16 journal articles |
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Arey J, Obermeyer G, Aschmann SM, Chattopadhyay S, Cusick RD, Atkinson R. Dicarbonyl products of the OH radical-initiated reaction of a series of aromatic hydrocarbons. Environmental Science & Technology 2009;43(3):683-689. |
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Aschmann SM, Arey J, Atkinson R. Extent of H-atom abstraction from OH + p-cymene and upper limits to the formation of cresols from OH + m-xylene and OH + p-cymene. Atmospheric Environment 2010;44(32):3970-3975. |
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Aschmann SM, Arey J, Atkinson R. Reactions of OH radicals with C6-C10 cycloalkanes in the presence of NO:isomerization of C7-C10 cycloalkoxy radicals. Journal of Physical Chemistry A 2011;115(50):14452-14461. |
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Aschmann SM, Nishino N, Arey J, Atkinson R. Kinetics of the reactions of OH radicals with 2-and 3-methylfuran, 2,3-and 2,5-dimethylfuran, and E-and Z-3-hexene-2,5-dione, and products of OH + 2,5-dimethylfuran. Environmental Science & Technology 2011;45(5):1859-1865. |
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Nishino N, Atkinson R, Arey J. Formation of nitro products from the gas-phase OH radical-initiated reactions of toluene, naphthalene, and biphenyl: effect of NO2 concentration. Environmental Science & Technology 2008;42(24):9203-9209. |
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Nishino N, Arey J, Atkinson R. Formation and reactions of 2-formylcinnamaldehyde in the OH radical-initiated reaction of naphthalene. Environmental Science & Technology 2009;43(5):1349-1353. |
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Nishino N, Arey J, Atkinson R. Yields of glyoxal and ring-cleavage co-products from the OH radical-initiated reactions of naphthalene and selected alkylnaphthalenes. Environmental Science & Technology 2009;43(22):8554-8560. |
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Nishino N, Arey J, Atkinson R. Formation of nitro-products from the gas-phase OH radical-initiated reactions of toluene, naphthalene and biphenyl: effect of NO2 concentration (erratum). Environmental Science & Technology 2010;44(9):3644-3645. |
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Nishino N, Arey J, Atkinson R. Formation yields of glyoxal and methyglyoxal from the gas-phase OH radical-initiated reactions of toluene, xylenes, and trimethylbenzenes as a function of NO2 concentration. The Journal of Physical Chemistry A 2010;114(37):10140-10147. |
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Nishino N, Arey J, Atkinson R. 2-Formylcinnamaldehyde formation yield from the OH radical-initiated reaction of naphthalene:effect of NO2 concentration. Environmental Science & Technology 2012;46(15):8198-8204. |
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Strollo CM, Ziemann PJ. Products and mechanism of secondary organic aerosol formation from the reaction of 3-methylfuran with OH radicals in the presence of NOx. Atmospheric Environment 2013;77:534-543. |
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Strollo CM, Ziemann PJ. Investigation of the formation of benzoyl peroxide, benzoic anhydride, and other potential aerosol products from gas-phase reactions of benzoylperoxy radicals. Atmospheric Environment 2016;130:202-210. |
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Ziemann PJ, Atkinson R. Kinetics, products, and mechanisms of secondary organic aerosol formation. Chemical Society Reviews 2012;41(19):6582-6605. |
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Zimmermann K, Atkinson R, Arey J, Kojima Y, Inazu K. Isomer distributions of molecular weight 247 and 273 nitro-PAHs in ambient samples, NIST diesel SRM, and from radical-initiated chamber reactions. Atmospheric Environment 2012;55:431-439. |
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Zimmermann K, Atkinson R, Arey J. Effect of NO2 concentration on dimethylnitronaphthalene yields and isomer distribution patterns from the gas-phase OH radical-initiated reactions of selected dimethylnaphthalenes. Environmental Science & Technology 2012;46(14):7535-7542. |
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Zimmermann K, Jariyasopit N, Massey Simonich SL, Tao S, Atkinson R, Arey J. Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with N2O5/NO3/NO2. Environmental Science & Technology 2013;47(15):8434-8442. |
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Supplemental Keywords:
absorption, chemicals, environmental chemistry, global climate, oxidants, particulates, PAHs, regional and climate models, toxics, tropospheric, VOCRelevant Websites:
http://www.envisci.ucr.edu/faculty/arey.html Exit
http://www.envisci.ucr.edu/faculty/atkinson.html Exit
http://www.envisci.ucr.edu/faculty/ziemann.html Exit
Progress and Final Reports:
Original AbstractThe 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.
Project Research Results
- 2011 Progress Report
- 2010 Progress Report
- 2009 Progress Report
- 2008 Progress Report
- Original Abstract
16 journal articles for this project