Effect of the OH Radical Scavenger Hydrogen Peroxide on Secondary Organic Aerosol Formation from α-Pinene Ozonolysis

Henry, Kaytlin M.; Donahue, Neil M.

doi:10.1080/02786826.2011.552926

Cited by 31 publications

(42 citation statements)

References 21 publications

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“…Hao et al (2011) reported a higher volatility and thus lower yields from OH dominated chemistry than for O 3 initiated oxidation. In contrast, there are other experiments which show that OH yields are a little higher than the O 3 yields (N. Donahue, personal communication, 2011;Henry and Donahue, 2011). Finally, we assumed that aerosol formation from isoprene can be neglected due to the low concentrations of this precursor at our study location (e.g.…”

Section: Gas-phase Chemistrymentioning

confidence: 65%

Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

et al. 2012

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Abstract. We study the combined effects of land surface conditions, atmospheric boundary layer dynamics and chemistry on the diurnal evolution of biogenic secondary organic aerosol in the atmospheric boundary layer, using a model that contains the essentials of all these components. First, we evaluate the model for a case study in Hyytiälä, Finland, and find that it is able to satisfactorily reproduce the observed dynamics and gas-phase chemistry. We show that the exchange of organic aerosol between the free troposphere and the boundary layer (entrainment) must be taken into account in order to explain the observed diurnal cycle in organic aerosol (OA) concentration. An examination of the budgets of organic aerosol and terpene concentrations show that the former is dominated by entrainment, while the latter is mainly driven by emission and chemical transformation. We systematically investigate the role of the land surface, which governs both the surface energy balance partitioning and terpene emissions, and the large-scale atmospheric process of vertical subsidence. Entrainment is especially important for the dilution of organic aerosol concentrations under conditions of dry soils and low terpene emissions. Subsidence suppresses boundary layer growth while enhancing entrainment. Therefore, it influences the relationship between organic aerosol and terpene concentrations. Our findings indicate that the diurnal evolution of secondary organic aerosols (SOA) in the boundary layer is the result of coupled effects of the land surface, dynamics of the atmospheric boundary layer, chemistry, and free troposphere conditions. This has potentially some consequences for the design of both field campaigns and large-scale modeling studies.

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Section: Gas-phase Chemistrymentioning

confidence: 65%

Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

et al. 2012

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“…It has been estimated that the ozonolysis of α-pinene results in the formation of OH radicals with a yield between 0.8 and 1.0 (Atkinson et al, 1997;Presto and Donahue, 2004). Therefore, without the use of an OH radical scavenger, a substantial fraction of α-pinene and other terpenes present in the mixture can be oxidised by OH radicals (Henry and Donahue, 2011). During the dark ageing experiments (Fig.…”

Section: Interactive Discussionmentioning

confidence: 99%

Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry

Kourtchev¹,

Doussin²,

Giorio³

et al. 2015

Preprint

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Abstract. Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidised molecules. Aerosol processing or further oxidation (ageing) of organic aerosol has been suggested to be responsible for their formation through heterogeneous uptake of oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several ageing processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography ultrahigh resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated ageing was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O/C ratios of the SOA components. None of the ageing processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH radical-initiated α-pinene oxidation had a significantly higher overall OSC and O/C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidised species in ambient biogenic SOA.

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“…The model flow time, τ model,flow , was determined to be the time at which the diameter of the hole at the centre of the halftorus decreased to half its original size, with simulations performed until τ model,flow was within 1 % of τ exp,flow . Based on prior observations of Newtonian behaviour in sucrose-water solutions Hosny et al (2013); Saggin and Coupland (2004), which are commonly used as proxies for SOM, the SOM was assumed to be Newtonian in nature for simulations.…”

Section: Simulations Of Fluid Flowmentioning

confidence: 99%

Effect of varying experimental conditions on the viscosity of <i>α</i>-pinene derived secondary organic material

et al. 2016

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Abstract. Knowledge of the viscosity of particles containing secondary organic material (SOM) is useful for predicting reaction rates and diffusion in SOM particles. In this study we investigate the viscosity of SOM particles as a function of relative humidity and SOM particle mass concentration, during SOM synthesis. The SOM was generated via the ozonolysis of α-pinene at < 5 % relative humidity (RH). Experiments were carried out using the poke-and-flow technique, which measures the experimental flow time (τexp, flow) of SOM after poking the material with a needle. In the first set of experiments, we show that τexp, flow increased by a factor of 3600 as the RH increased from < 0.5 RH to 50 % RH, for SOM with a production mass concentration of 121 µg m−3. Based on simulations, the viscosities of the particles were between 6  ×  105 and 5  ×  107 Pa s at < 0.5 % RH and between 3  ×  102 and 9  ×  103 Pa s at 50 % RH. In the second set of experiments we show that under dry conditions τexp, flow decreased by a factor of 45 as the production mass concentration increased from 121 to 14 000 µg m−3. From simulations of the poke-and-flow experiments, the viscosity of SOM with a production mass concentration of 14 000 µg m−3 was determined to be between 4  ×  104 and 1.5  ×  106 Pa s compared to between 6  ×  105 and 5  ×  107 Pa s for SOM with a production mass concentration of 121 µg m−3. The results can be rationalized by a dependence of the chemical composition of SOM on production conditions. These results emphasize the shifting characteristics of SOM, not just with RH and precursor type, but also with the production conditions, and suggest that production mass concentration and the RH at which the viscosity was determined should be considered both when comparing laboratory results and when extrapolating these results to the atmosphere.

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Effect of the OH Radical Scavenger Hydrogen Peroxide on Secondary Organic Aerosol Formation from α-Pinene Ozonolysis

Cited by 31 publications

References 21 publications

Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry

Effect of varying experimental conditions on the viscosity of <i>α</i>-pinene derived secondary organic material

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Effect of the OH Radical Scavenger Hydrogen Peroxide on Secondary Organic Aerosol Formation from α-Pinene Ozonolysis

Cited by 31 publications

References 21 publications

Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry

Effect of varying experimental conditions on the viscosity of &lt;i&gt;α&lt;/i&gt;-pinene derived secondary organic material

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Effect of varying experimental conditions on the viscosity of <i>α</i>-pinene derived secondary organic material