Organic reactions increasing the absorption index of atmospheric sulfuric acid aerosols

Nozière, Barbara; Esteve, Williams

doi:10.1029/2004gl021942

Cited by 72 publications

(66 citation statements)

References 17 publications

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“…While hexanal has no absorption features in the visible region, the long wavelength edge of the aldol spectrum extends into the visible region, leading to the observed yellow color of the product solution. This characteristic has been attributed to polymerization by others (Limbeck et al, 2003;Noziere and Esteve, 2005;Zhao et al, 2005). For example, Noziere and Esteve (2005) have suggested in the acid-catalyzed reaction of acetaldehyde the appearance of a product peak at 350 nm is due to the formation of three conjugated double bonds, which would occur if three acetaldehyde molecules reacted.…”

Section: Optical Propertiesmentioning

confidence: 97%

“…This characteristic has been attributed to polymerization by others (Limbeck et al, 2003;Noziere and Esteve, 2005;Zhao et al, 2005). For example, Noziere and Esteve (2005) have suggested in the acid-catalyzed reaction of acetaldehyde the appearance of a product peak at 350 nm is due to the formation of three conjugated double bonds, which would occur if three acetaldehyde molecules reacted. In this study, 1 H-NMR data indicates that no polymerization has occurred in the aldol condensation reaction of hexanal, implying that the conjugation in the aldol condensation product alone accounts for the color of the product.…”

Section: Optical Propertiesmentioning

confidence: 97%

“…Many studies have suggested that in order for the organic vapors to be incorporated into the aerosol, oligomerization or polymerization must occur (Jang and Kamens, 2001;Czoschke et al, 2003;Jang et al, 2003aJang et al, , b, 2002Jang et al, , 2005Kalberer et al, 2004;Tolocka et al, 2004;Noziere and Esteve, 2005). However, while it is clear that acidic aerosols take up more organic mass than non-acidic aerosols, the identification of reaction pathways (if a reaction is indeed occurring) and identification of specific molecular products in these studies has been incomplete.…”

Section: Introductionmentioning

confidence: 97%

“…For example, UV-VIS spectra of the acid-catalyzed reaction products of acetaldehyde and isoprene have been found to have absorption features which extend to visible wavelengths (Limbeck et al, 2003;Noziere and Esteve, 2005). The addition of light-absorbing organic material into atmospheric aerosols may have important consequences in the aerosol direct effect on climate change.…”

Section: Introductionmentioning

confidence: 99%

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Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

Garland

Elrod

Kincaid

et al. 2006

Atmospheric Environment

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While it is well established that organics compose a large fraction of the atmospheric aerosol mass, the mechanisms through which organics are incorporated into atmospheric aerosols are not well understood. Acid-catalyzed reactions of compounds with carbonyl groups have recently been suggested as important pathways for transfer of volatile organics into acidic aerosols. In the present study, we use the aerodyne aerosol mass spectrometer (AMS) to probe the uptake of gasphase hexanal into ammonium sulfate and sulfuric acid aerosols. While both deliquesced and dry non-acidic ammonium sulfate aerosols showed no organic uptake, the acidic aerosols took up substantial amounts of organic material when exposed to hexanal vapor. Further, we used 1 H-NMR, Fourier transform infrared (FTIR) spectroscopy and GC-MS to identify the products of the acid-catalyzed reaction of hexanal in acidic aerosols. Both aldol condensation and hemiacetal products were identified, with the dominant reaction products dependent upon the initial acid concentration of the aerosol. The aldol condensation product was formed only at initial concentrations of 75-96 wt% sulfuric acid in water. The hemiacetal was produced at all sulfuric acid concentrations studied, 30-96 wt% sulfuric acid in water. Aerosols up to 88.4 wt% organic/11.1 wt% H 2 SO 4 /0.5 wt% water were produced via these two dimerization reaction pathways. The UV-VIS spectrum of the isolated aldol condensation product, 2-butyl 2-octenal, extends into the visible region, suggesting these reactions may impact aerosol optical properties as well as aerosol composition. In contrast to previous suggestions, no polymerization of hexanal or its products was observed at any sulfuric acid concentration studied, from 30 to 96 wt% in water. r

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Section: Optical Propertiesmentioning

confidence: 97%

Section: Optical Propertiesmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

Garland

Elrod

Kincaid

et al. 2006

Atmospheric Environment

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“…A recent modeling study has investigated the role of dicarboxylic acids in atmospheric ice formation and found that changes in water uptake can affect the size of particles containing organics and thus can explain the observations that organic containing particles are less efficient at ice nucleation (Kärcher and Koop, 2005). While ice nucleation has mainly been studied for mixtures of dicarboxylic acids with ammonium sulfate, other carbonyl-containing compounds, such as aldehydes and ketones, have been investigated at warmer temperatures to probe acid-catalyzed reactions with sulfuric acid (Iraci and Tolbert, 1997;Jang et al, 2002;Nozière and Riemer, 2003;Michelsen et al, 2004;Garland et al, 2006;Liggio et al, 2005;Nozière and Esteve, 2005;Zhao et al, 2005). An important characteristic of these acid-catalyzed reactions is the ability to form products of lower vapor pressure and solubility as well as higher melting points than the initial reactant compounds.…”

Section: Introductionmentioning

confidence: 99%

Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation

et al. 2006

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Abstract.Using an aerosol flow tube apparatus, we have studied the effects of aliphatic aldehydes (C 3 to C 10 ) and ketones (C 3 and C 9 ) on ice nucleation in sulfuric acid aerosols. Mixed aerosols were prepared by combining an organic vapor flow with a flow of sulfuric acid aerosols over a small mixing time (∼60 s) at room temperature. No acid-catalyzed reactions were observed under these conditions, and physical uptake was responsible for the organic content of the sulfuric acid aerosols. In these experiments, aerosol organic content, determined by a Mie scattering analysis, was found to vary with the partial pressure of organic, the flow tube temperature, and the identity of the organic compound. The physical properties of the organic compounds (primarily the solubility and melting point) were found to play a dominant role in determining the inferred mode of nucleation (homogenous or heterogeneous) and the specific freezing temperatures observed. Overall, very soluble, low-melting organics, such as acetone and propanal, caused a decrease in aerosol ice nucleation temperatures when compared with aqueous sulfuric acid aerosol. In contrast, sulfuric acid particles exposed to organic compounds of eight carbons and greater, of much lower solubility and higher melting temperatures, nucleate ice at temperatures above aqueous sulfuric acid aerosols. Organic compounds of intermediate carbon chain length, C 4 -C 7 , (of intermediate solubility and melting temperatures) nucleated ice at the same temperature as aqueous sulfuric acid aerosols. Interpretations and implications of these results for cirrus cloud formation are discussed.

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Biomass burning dominates brown carbon absorption in the rural southeastern United States

Washenfelder

Attwood

Brock

et al. 2015

Geophysical Research Letters

249

243

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Brown carbon aerosol consists of light-absorbing organic particulate matter with wavelength-dependent absorption. Aerosol optical extinction, absorption, size distributions, and chemical composition were measured in rural Alabama during summer 2013. The field site was well located to examine sources of brown carbon aerosol, with influence by high biogenic organic aerosol concentrations, pollution from two nearby cities, and biomass burning aerosol. We report the optical closure between measured dry aerosol extinction at 365 nm and calculated extinction from composition and size distribution, showing agreement within experiment uncertainties. We find that aerosol optical extinction is dominated by scattering, with single-scattering albedo values of 0.94 ± 0.02. Black carbon aerosol accounts for 91 ± 9% of the total carbonaceous aerosol absorption at 365 nm, while organic aerosol accounts for 9 ± 9%. The majority of brown carbon aerosol mass is associated with biomass burning, with smaller contributions from biogenically derived secondary organic aerosol.

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Organic reactions increasing the absorption index of atmospheric sulfuric acid aerosols

Cited by 72 publications

References 17 publications

Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation

Biomass burning dominates brown carbon absorption in the rural southeastern United States

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