Stereochemical transfer to atmospheric aerosol particles accompanying the oxidation of biogenic volatile organic compounds

Ebben, C. J.; Zorn, S. R.; Lee, Seungbok; Artaxo, Paulo; Martin, Scot T.; Geiger, Franz M.

doi:10.1029/2011gl048599

Cited by 25 publications

(21 citation statements)

References 36 publications

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“…Comparable filter loadings (upper limits of 20 μg vs 285 μg) and similar particle sizes (about 93 nm) were used for the present flow tube and 2011 chamber studies. 31,48 Control studies carried out as part of this present work show that a filter containing α-pinene-derived SOM from the flow tube produced higher SFG signal intensity than SOM transferred from the same Teflon filter onto a fused silica window when probed in external reflection geometry (see Supporting Information). The weak SFG signal in the latter case may be due to the small quantity of material transferred from the Teflon filter onto the fused silica window.…”

Section: Resultsmentioning

confidence: 93%

“…Control experiments using a HEPA filter to remove the SOA particles from the chamber outflow while sending the vapor phase over collection filters resulted in no appreciable SFG signal from the collection filter. 48 We conclude that the high volatility of the SOA gas phase species prevents them from binding irreversibly to the Teflon filter.…”

Section: Limit Of Detection Analysis and Condensational Versus Coagulmentioning

confidence: 97%

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Vibrational Sum Frequency Generation Spectroscopy of Secondary Organic Material Produced by Condensational Growth from α-Pinene Ozonolysis

et al. 2013

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Secondary organic material (SOM) was produced in a flow tube from α-pinene ozonolysis, and collected particles were analyzed spectroscopically via a nonlinear coherent vibrational spectroscopic technique, namely sum frequency generation (SFG). The SOM precursor α-pinene was injected into the flow tube reactor at concentrations ranging from 0.125 ± 0.01 ppm to 100 ± 3 ppm. The oxidant ozone was varied from 0.15 ± 0.02 to 194 ± 2 ppm. The residence time was 38 ± 1 s. The integrated particle number concentrations, studied using a scanning mobility particle sizer (SMPS), varied from no particles produced up to (1.26 ± 0.02) × 10(7) cm(-3) for the matrix of reaction conditions. The mode diameters of the aerosols increased from 7.7 nm (geometric standard deviation (gsd), 1.0) all the way to 333.8 nm (gsd, 1.9). The corresponding volume concentrations were as high as (3.0 ± 0.1) × 10(14) nm(3) cm(-3). The size distributions indicated access to different particle growth stages, namely condensation, coagulation, or combination of both, depending on reaction conditions. For filter collection and subsequent spectral analysis, reaction conditions were selected that gave a mode diameter of 63 ± 3 nm and 93 ± 3 nm, respectively, and an associated mass concentration of 12 ± 2 μg m(-3) and (1.2 ± 0.1) × 10(3) μg m(-3) for an assumed density of 1200 kg m(-3). Teflon filters loaded with 24 ng to 20 μg of SOM were analyzed by SFG. The SFG spectra obtained from particles formed under condensational and coagulative growth conditions were found to be quite similar, indicating that the distribution of SFG-active C-H oscillators is similar for particles prepared under both conditions. The spectral features of these flow-tube particles agreed with those prepared in an earlier study that employed the Harvard Environmental Chamber. The SFG intensity was found to increase linearly with the number of particles, consistent with what is expected from SFG signal production from particles, while it decreased at higher mass loadings of 10 and 20 μg, consistent with the notion that SFG probes the top surface of the SOM material following the complete coverage of the filter. The linear increase in SFG intensity with particle density also supports the notion that the average number of SFG active oscillators per particle is constant for a given particle size, that the particles are present on the collection filters in a random array, and that the particles are not coalesced. The limit of detection of SFG intensity was established as 24 ng of mass on the filter, corresponding to a calculated density of about 100 particles in the laser spot. As established herein, the technique is applicable for detecting low particle number or mass concentrations in ambient air. The related implication is that SFG is useful for short collection times and would therefore provide increased temporal resolution in a locally evolving atmospheric environment.

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Section: Resultsmentioning

confidence: 93%

Section: Limit Of Detection Analysis and Condensational Versus Coagulmentioning

confidence: 97%

Vibrational Sum Frequency Generation Spectroscopy of Secondary Organic Material Produced by Condensational Growth from α-Pinene Ozonolysis

et al. 2013

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“…The synthetic epoxide and tetraol samples were analyzed at room temperature by SFG by contacting a fused silica window with (a) their equilibrium vapor pressure (Lide, 1997) and (b) their condensed phase following spin coating of the sample dissolved in deuterated methanol. Synthetic SOA particle material, condensed over the course of several days onto 50 nm-sized ammonium sulfate seed particles during the reaction of isoprene and OH radicals at the HEC and subsequently collected on Teflon filters as described in our earlier work (Ebben et al, 2011a), was probed by SFG by pressing a fused silica window against a Teflon filter containing SOA particle material (Ebben et al, 2011b(Ebben et al, , 2012. Finally, field-derived SOA particle material, collected on nucleopore impactor substrates sampled using a micro-orifice uniformdeposit impactor (MOUDI) (Marple et al, 1991) in the central Amazon Basin from 9 April 2008 to 17 April 2008 at the site of the AMAZE-08 campaign (Martin et al, 2010a), was probed by SFG in the same way as the synthetic SOA particle material prepared at the HEC.…”

Section: Sample Configurationsmentioning

confidence: 99%

Towards the identification of molecular constituents associated with the surfaces of isoprene-derived secondary organic aerosol (SOA) particles

et al. 2014

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Abstract. Secondary organic aerosol (SOA) particle formation ranks among the least understood chemical processes in the atmosphere, rooted in part in the lack of knowledge about chemical composition and structure at the particle surface, and little availability of reference compounds needed for benchmarking and chemical identification in pure and homogenous form. Here, we synthesize and characterize SOA particle constituents consisting of the isoprene oxidation products α-, δ-, and cis- and trans-β-IEPOX (isoprene epoxide), as well as syn- and anti-2-methyltetraol. Paying particular attention to their phase state (condensed vs. vapor), we carry out a surface-specific and orientationally selective chemical analysis by vibrational sum frequency generation (SFG) spectroscopy of these compounds in contact with a fused silica window. Comparison to the vibrational SFG spectra of synthetic isoprene-derived SOA particle material prepared at the Harvard Environmental Chamber yields a plausible match with trans-β-IEPOX, suggesting it is an abundant species on their surfaces, while the other species studied here, if present, appear to be SFG inactive and thus likely to be localized in a centrosymmetric environment, e.g., the particle bulk. No match is found for authentic SOA particle material collected at the site of the Amazonian Aerosol Characterization Experiment (AMAZE-08) with the surface SFG spectra of the compounds surveyed here, yet we cannot rule out this mismatch being attributable to differences in molecular orientation. The implications of our findings for SOA formation are discussed in the context of condensational particle growth and reactivity.

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“…Chiral molecules do not possess a center of inversion, and, using the proper polarization combination, their SFG responses can be nonzero and originate from the surface and the bulk of the aerosol particle, depending on symmetry. Details regarding the role of chirality in SOA particles are discussed in our recently published work (Ebben et al, 2011;Martinez et al, 2011). We emphasize that the present work is carried out using the SSPpolarization combination, which is insensitive to molecular chirality and yields SFG signals from the CH oscillators that are located at the surface of the aerosol particles as opposed to those that are located in the bulk.…”

Section: Sfg Theorymentioning

confidence: 99%

Contrasting organic aerosol particles from boreal and tropical forests during HUMPPA-COPEC-2010 and AMAZE-08 using coherent vibrational spectroscopy

Ebben¹,

Martinez²,

Shrestha³

et al. 2011

Preprint

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We present the vibrational sum frequency generation spectra of organic particles collected in a boreal forest in Finland and a tropical forest in Brazil. These spectra are compared to those of secondary organic material produced in the Harvard Environmental Chamber. By comparing coherent vibrational spectra of a variety of terpene and olefin reference compounds, along with the secondary organic material synthesized in the environmental chamber, we show that submicron aerosol particles sampled in Southern Finland during HUMPPA-COPEC-2010 are composed to a large degree of material similar in chemical composition to synthetic α-pinene-derived material. For material collected in Brazil as part of AMAZE-08, the organic component is found to be chemically complex in the coarse mode but highly uniform in the fine mode. When combined with histogram analyses of the isoprene and monoterpene abundance recorded during the HUMPPA-COPEC-2010 and AMAZE-08 campaigns, the findings presented here indicate that if air is rich in monoterpenes, submicron-sized secondary aerosol particles that form under normal OH and O<sub>3</sub> concentration levels can be described in terms of their hydrocarbon content as being similar to α-pinene-derived model secondary organic aerosol particles. If the isoprene concentration dominates the chemical composition of organic compounds in forest air, then the hydrocarbon component of secondary organic material in the submicron size range is not simply well-represented by that of isoprene-derived model secondary organic aerosol particles but is more complex. Throughout the climate-relevant size range of the fine mode, however, we find that the chemical composition of the secondary organic particle material from such air is invariant with size, suggesting that the particle growth does not change the chemical composition of the hydrocarbon component of the particles in a significant way

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Stereochemical transfer to atmospheric aerosol particles accompanying the oxidation of biogenic volatile organic compounds

Cited by 25 publications

References 36 publications

Vibrational Sum Frequency Generation Spectroscopy of Secondary Organic Material Produced by Condensational Growth from α-Pinene Ozonolysis

Vibrational Sum Frequency Generation Spectroscopy of Secondary Organic Material Produced by Condensational Growth from α-Pinene Ozonolysis

Towards the identification of molecular constituents associated with the surfaces of isoprene-derived secondary organic aerosol (SOA) particles

Contrasting organic aerosol particles from boreal and tropical forests during HUMPPA-COPEC-2010 and AMAZE-08 using coherent vibrational spectroscopy

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