Laboratory observation of oligomers in the aerosol from isoprene/NO<sub>x</sub> photooxidation

Dommen, Josef; Metzger, Axel; Duplissy, Jonathan; Kalberer, Markus; Alfarra, M. Rami; Gascho, A.; Weingärtner, E.; Prévôt, Andrê S. H.; Verheggen, B.; Baltensperger, Urs

doi:10.1029/2006gl026523

Cited by 176 publications

(226 citation statements)

References 24 publications

(39 reference statements)

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“…5). Dommen et al (32) observed lowervolatility isoprene SOA (which is consistent with the formation of oligomers) to form under dry rather than humid conditions, which is consistent with a mechanism that involves decomposition of the C 4 -hydroxynitrate-PAN into 2-MG and allows for subsequent esterification of 2-MG into the observed oligoesters. We do not, however, have conclusive chemical evidence to support the hypothesis that the C 4 -hydroxynitrate-PAN is the main precursor to the isoprene high-NO x SOA.…”

Section: Identification Of Mpan As Key Intermediate In Formation Of Ssupporting

confidence: 53%

Reactive intermediates revealed in secondary organic aerosol formation from isoprene

Surratt

Chan

Eddingsaas

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

940

1,432

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Isoprene is a significant source of atmospheric organic aerosol; however, the oxidation pathways that lead to secondary organic aerosol (SOA) have remained elusive. Here, we identify the role of two key reactive intermediates, epoxydiols of isoprene (IEPOX ¼ β-IEPOX þ δ-IEPOX) and methacryloylperoxynitrate (MPAN), which are formed during isoprene oxidation under low-and high-NO x conditions, respectively. Isoprene low-NO x SOA is enhanced in the presence of acidified sulfate seed aerosol (mass yield 28.6%) over that in the presence of neutral aerosol (mass yield 1.3%). Increased uptake of IEPOX by acid-catalyzed particle-phase reactions is shown to explain this enhancement. Under high-NO x conditions, isoprene SOA formation occurs through oxidation of its secondgeneration product, MPAN. The similarity of the composition of SOA formed from the photooxidation of MPAN to that formed from isoprene and methacrolein demonstrates the role of MPAN in the formation of isoprene high-NO x SOA. Reactions of IEPOX and MPAN in the presence of anthropogenic pollutants (i.e., acidic aerosol produced from the oxidation of SO 2 and NO 2 , respectively) could be a substantial source of "missing urban SOA" not included in current atmospheric models.acid-catalyzed particle-phase reactions | epoxides | methacryloylperoxynitrate | organosulfates I soprene (2-methyl-1,3-butadiene, C 5 H 8 ) is the most abundant nonmethane hydrocarbon emitted into the Earth's atmosphere, with emissions estimated to be 440-660 TgC yr −1 (1). The atmospheric hydroxyl (OH) radical-initiated oxidation of isoprene, so-called photooxidation, plays a key role in establishing the balance of hydrogen oxide (HO x ¼ OH þ HO 2 ) radicals in vegetated areas (2, 3) and influences urban ozone formation in populated areas blanketed with biogenic emissions (4). Formation of low-volatility compounds during isoprene oxidation has been estimated to be the single largest source of atmospheric organic aerosol [i.e., secondary organic aerosol (SOA)] (5-8).The photooxidation of unsaturated volatile organic compounds (VOCs) proceeds through formation of a hydroxy peroxy (RO 2 ) radical, the fate of which depends on the concentration of nitrogen oxides (NO x ¼ NO þ NO 2 ). Higher SOA yields from isoprene are observed under low-NO x (or NO x -free) conditions; in this regime, RO 2 radicals react primarily with HO 2 , a pathway that tends to produce lower-volatility oxidation products than that involving the reaction of RO 2 with NO (9-11). Under high-NO x conditions, RO 2 radicals react with NO to produce alkoxy (RO) radicals, or as a minor pathway, organic nitrates (RONO 2 ). For small VOCs (≤C 10 ), like isoprene, these RO radicals generally fragment into smaller more volatile products, resulting in small amounts of SOA (9-11). Despite the fact that SOA from isoprene has been extensively studied (8), the chemical pathways to its formation under both low-and high-NO x conditions have remained unclear. In this study we examine the mechanism of isoprene SOA formation in these two ...

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Section: Identification Of Mpan As Key Intermediate In Formation Of Ssupporting

confidence: 53%

Reactive intermediates revealed in secondary organic aerosol formation from isoprene

Surratt

Chan

Eddingsaas

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

940

1,432

View full text Add to dashboard Cite

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“…Isoprene is also known to have a small but significant yield of SOA mass formation. Depending on seed aerosol, initial precursor concentration and relative NO x levels, SOA yields in the range of 1-5 % were reported in the literature (Kroll et al, 2005;Dommen et al, 2006;Kroll et al, 2006;Dommen et al, 2009). Including SOA from isoprene in calculations of the global SOA burden increases SOA by factors between 0.5 and 2 depending on scenarios used (Henze and Seinfeld, 2006).…”

Section: Resultsmentioning

confidence: 98%

Isoprene in poplar emissions: effects on new particle formation and OH concentrations

Kiendler‐Scharr¹,

Andres²,

Bachner³

et al. 2012

Atmos. Chem. Phys.

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Abstract. Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m −2 s −1 in non-transgenic controls (wild type WT) and nearly zero (<0.5 nmol m −2 s −1 ) in isoprene emission-repressed plants (line RA22), respectively. Nucleation rates of up to 3600 cm −3 s −1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C 5 D 8 ) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3 % of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

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“…Note that Virtanen et al (2010) found that particles formed in the plant chamber are in a glassy state, and we cannot rule out the possibility that the particles are initially in a liquid state, but become more glasslike and less volatile with the aging. Formation of lowvolatility components of SOA formed from photooxidation of α-pinene (Paulsen et al, 2006;Baltensperger et al, 2005), aromatic compounds (Kalberer et al, 2004;Baltensperger et al, 2005), and isoprene (Dommen et al, 2006) have also been observed even after the completion of gas-phase chemistry. Those components are usually as a result of formation of high molecular weight compounds from oligomerization or polymerization processes.…”

Section: Oh-and O 3 -Initiated Chemistrymentioning

confidence: 99%

“…Further oxidation of semi-volatile products in the gas and particle phase Chan et al, 2007) and secondary generation products (Ng et al, 2006) caused by OH and O 3 could also alter final SOA production. Moreover, organic products in the condensed phase may also undergo chemical reactions, affecting their physicochemical properties (Joutsensaari et al, 2004) and volatility (Paulsen et al, 2006;Dommen et al, 2006;Baltensperger et al, 2005;Kalberer et al, 2004). The volatility of 30 nm and 50 nm diameter SOA at temperature of 150 • C, formed in the OH-dominated and O 3 -initiated chemical systems, is displayed in Fig.…”

Section: Oh-and O 3 -Initiated Chemistrymentioning

confidence: 99%

Mass yields of secondary organic aerosols from the oxidation of α-pinene and real plant emissions

et al. 2011

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Abstract. Biogenic volatile organic compounds (VOCs) are a significant source of global secondary organic aerosol (SOA); however, quantifying their aerosol forming potential remains a challenge. This study presents smog chamber laboratory work, focusing on SOA formation via oxidation of the emissions of two dominant tree species from boreal forest area, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies), by hydroxyl radical (OH) and ozone (O 3 ). Oxidation of α-pinene was also studied as a reference system. Tetramethylethylene (TME) and 2-butanol were added to control OH and O 3 levels, thereby allowing SOA formation events to be categorized as resulting from either OHdominated or O 3 -initiated chemistry. SOA mass yields from α-pinene are consistent with previous studies while the yields from the real plant emissions are generally lower than that from α-pinene, varying from 1.9% at an aerosol mass loading of 0.69 µg m −3 to 17.7% at 26.0 µg m −3 . Mass yields from oxidation of real plant emissions are subject to the interactive effects of the molecular structures of plant emissions and their reaction chemistry with OH and O 3 , which Correspondence to: L. Q. Hao (hao.liqing@uef.fi) lead to variations in condensable product volatility. SOA formation can be reproduced with a two-product gas-phase partitioning absorption model in spite of differences in the source of oxidant species and product volatility in the real plant emission experiments. Condensable products from OH-dominated chemistry showed a higher volatility than those from O 3 -initiated systems during aerosol growth stage. Particulate phase products became less volatile via aging process which continued after input gas-phase oxidants had been completely consumed.

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Laboratory observation of oligomers in the aerosol from isoprene/NO_x photooxidation

Cited by 176 publications

References 24 publications

Reactive intermediates revealed in secondary organic aerosol formation from isoprene

Reactive intermediates revealed in secondary organic aerosol formation from isoprene

Isoprene in poplar emissions: effects on new particle formation and OH concentrations

Mass yields of secondary organic aerosols from the oxidation of α-pinene and real plant emissions

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Laboratory observation of oligomers in the aerosol from isoprene/NOx photooxidation

Cited by 176 publications

References 24 publications

Reactive intermediates revealed in secondary organic aerosol formation from isoprene

Reactive intermediates revealed in secondary organic aerosol formation from isoprene

Isoprene in poplar emissions: effects on new particle formation and OH concentrations

Mass yields of secondary organic aerosols from the oxidation of α-pinene and real plant emissions

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Product

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Laboratory observation of oligomers in the aerosol from isoprene/NO_x photooxidation