Atmospheric photooxidation of isoprene part II: The ozone‐isoprene reaction

Paulson, Suzanne E.; Flagan, Richard C.; Seinfeld, John H.

doi:10.1002/kin.550240110

Cited by 172 publications

(150 citation statements)

References 25 publications

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“…However, recent theoretical results suggest the contrary (Mackenzie-Rae et al, 2016), with steric effects raising the energy barrier for entry to the more substituted double bond, resulting in addition to the less substituted double bond in α-phellandrene being favoured. This finding is consistent with experimental evidence for isoprene, where methacrolein, not methyl vinyl ketone, is the favoured first-generation product (Paulson et al, 1992;Grosjean et al, 1993;Aschmann and Atkinson, 1994;Rickard et al, 1999). Nevertheless, the average energy difference for addition to the two double bonds is minor, with both entry channels expected to be important.…”

Section: Modelling Rate Constants and Oh Yieldssupporting

confidence: 89%

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

et al. 2017

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Abstract. The ozonolysis of α-phellandrene, a highly reactive conjugated monoterpene largely emitted by Eucalypt species, is characterised in detail for the first time using a smog chamber at the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. Gas-phase species were monitored by a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF), with yields from a large number of products obtained, including formaldehyde (5-9 %), acetaldehyde (0.2-8 %), glyoxal (6-23 %), methyl glyoxal (2-9 %), formic acid (22-37 %) and acetic acid (9-22 %). Higher m/z second-generation oxidation products were also observed, with products tentatively identified according to a constructed degradation mechanism. OH yields from α-phellandrene and its first-generation products were found to be 35 ± 12 and 15 ± 7 %, respectively, indicative of prominent hydroperoxide channels. An average first-generation rate coefficient was determined as 1.0 ± 0.7 × 10 −16 cm 3 molecule −1 s −1 at 298 K, showing ozonolysis as a dominant loss process for both α-phellandrene and its first-generation products in the atmosphere. Endocyclic conjugation in α-phellandrene was also found to be conducive to the formation of highly condensible products with a large fraction of the carbon mass partitioning into the aerosol phase, which was monitored with a scanning mobility particle sizer (SMPS) and a high-resolution timeof-flight aerosol mass spectrometer (AMS). Nucleation was observed almost instantaneously upon ozonolysis, indicating the rapid formation of extremely low-volatility compounds. Particle nucleation was found to be suppressed by the addition of either NO 2 or a Criegee scavenger, with it being proposed that stabilised Criegee intermediates are important for new particle formation in the system. Aerosol yields ranged from 25 to 174 % depending on mass loadings, with both first-and second-generation products identified as large contributors to the aerosol mass. In short, with a high chemical reactivity and aerosol-forming propensity, α-phellandrene is expected to have an immediate impact on the local environment to which it is emitted, with ozonolysis likely to be an important contributor to the significant blue haze and frequent nocturnal nucleation events observed over Eucalypt forests.

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Section: Modelling Rate Constants and Oh Yieldssupporting

confidence: 89%

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

et al. 2017

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“…30% of the isoprene concentration. This is close to the yields of 25 % and 24 % measured in chamber experiments by Paulson et al (1992) and Atkinson (1994),…”

Section: Concentrations Of Reaction Products Of Terpenessupporting

confidence: 88%

Sesquiterpenes identified as key species for atmospheric chemistry in boreal forest by terpenoid and OVOC measurements

Hellén

Praplan

Tykkä

et al. 2018

Preprint

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Abstract. Concentrations of terpenoids (isoprene, monoterpenes, sesquiterpenes) and oxygenated volatile organic compounds (OVOCs, i.e. aldehydes, alcohols, acetates and volatile organic acids) were investigated during two years at a boreal forest site in Hyytiälä, Finland, using in situ gas chromatograph-mass spectrometers (GC-MS). Seasonal and diurnal variations of terpenoid and OVOC concentrations as well as their relationship with meteorological factors were studied.Of the studied VOCs, C2-C7 unbranched volatile organic acids (VOAs) were found to have the highest concentrations mainly 20 due to their low reactivity. Of the terpenoids, monoterpenes (MTs) had highest concentrations at the site, but also 7 different highly reactive sesquiterpenes (SQTs) were detected. Monthly and daily mean concentrations of most terpenoids, aldehydes and VOAs were found to be highly dependent on the temperature. Highest exponential correlation with temperature was found for a SQT (β-caryophyllene) in summer. The diurnal variations of the concentrations could be explained by sources, sinks and vertical mixing. Especially the diurnal variations of MT concentrations were strongly affected by vertical mixing. Based on 25 the temperature correlations and mixing layer height simple proxies were developed for estimating MT and SQT concentrations.To estimate the importance of different compound groups and compounds for the local atmospheric chemistry, reactivity with main oxidants (OH, NO3 and O3) and production rates of oxidation products (OxPR) were calculated. MTs dominated OH and NO3 radical chemistry, but SQTs had a major impact on ozone chemistry, even though concentrations of SQT were 30 times 30 lower than MT concentrations. SQTs were the most important also for the production of oxidation products. Since SQTs have high secondary organic aerosol (SOA) yields, results clearly indicate the importance of SQTs for local SOA production.Atmos. Chem. Phys. Discuss., https://doi

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“…Herein, the OH reached steady state concentrations of about 3×10 7 cm −3 , as described above. Ozonolysis alone did not induce new particle formation with detectable yields, although all SQT and a portion of the MT were consumed by ozone (including a contribution by dark OH arising from the ozonolysis of unsaturated VOC, since we did not use OH-scavengers, see Atkinson and Aschmann, 1993;Paulson et al, 1992Paulson et al, , 1998.…”

Section: Resultsmentioning

confidence: 99%

Photochemical production of aerosols from real plant emissions

Mentel¹,

Wildt²,

et al. 2009

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Abstract. Emission of biogenic volatile organic compounds (VOC) which on oxidation form secondary organic aerosols (SOA) can couple the vegetation with the atmosphere and climate. Particle formation from tree emissions was investigated in a new setup: a plant chamber coupled to a reaction chamber for oxidizing the plant emissions and for forming SOA. Emissions from the boreal tree species birch, pine, and spruce were studied. In addition, α-pinene was used as reference compound. Under the employed experimental conditions, OH radicals were essential for inducing new particle formation, although O 3 (≤80 ppb) was always present and a fraction of the monoterpenes and the sesquiterpenes reacted with ozone before OH was generated. Formation rates of 3 nm particles were linearly related to the VOC carbon mixing ratios, as were the maximum observed volume and the condensational growth rates. For all trees, the threshold of new particle formation was lower than for α-pinene. It was lowest for birch which emitted the largest fraction of oxygenated VOC (OVOC), suggesting that OVOC may play a role in the nucleation process. Incremental mass yields were ≈5% for pine, spruce and α-pinene, and ≈10% for birch. α-Pinene was a good model compound to describe the yield and the growth of SOA particles from coniferous emissions. The mass fractional yields agreed well with observations for boreal forests. Despite the somewhat enhanced VOC and OH concentrations our results may be up-scaled to eco-system level. Using the mass fractional yields observed for the tree Correspondence to: Th. F. Mentel (t.mentel@fz-juelich.de) emissions and weighting them with the abundance of the respective trees in boreal forests SOA mass concentration calculations agree within 6% with field observations. For a future VOC increase of 50% we predict a particle mass increase due to SOA of 19% assuming today's mass contribution of pre-existing aerosol and oxidant levels.

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Atmospheric photooxidation of isoprene part II: The ozone‐isoprene reaction

Cited by 172 publications

References 25 publications

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

Sesquiterpenes identified as key species for atmospheric chemistry in boreal forest by terpenoid and OVOC measurements

Photochemical production of aerosols from real plant emissions

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Atmospheric photooxidation of isoprene part II: The ozone‐isoprene reaction

Cited by 172 publications

References 25 publications

Ozonolysis of &lt;i&gt;α&lt;/i&gt;-phellandrene – Part 1: Gas- and particle-phase characterisation

Ozonolysis of &lt;i&gt;α&lt;/i&gt;-phellandrene – Part 1: Gas- and particle-phase characterisation

Sesquiterpenes identified as key species for atmospheric chemistry in boreal forest by terpenoid and OVOC measurements

Photochemical production of aerosols from real plant emissions

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Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation