Interfacial photochemistry of biogenic surfactants: a major source of abiotic volatile organic compounds

Films of biogenic compounds exposed to the atmosphere are ubiquitously found on the surfaces of cloud droplets, aerosol particles, buildings, plants, soils and the ocean. These air/water interfaces host countless amphiphilic compounds concentrated there with respect to in bulk water, leading to a unique chemical environment. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants and VOC production. In particular, irradiation of samples containing solely biofilm cells without matrix components exhibited the strongest VOC production upon irradiation. In agreement with previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC productionviaperoxy radical chemistry. Up to now, such VOC emissions were directly accounted to high biological activity in surface waters. However, the results obtained suggest that abiotic photochemistry can lead to similar emissions into the atmosphere, especially in less biologically-active regions. Furthermore, chamber experiments suggest that oxidation (O3/OH radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth’s radiation budget.

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Aqueous-phase behavior of glyoxal and methylglyoxal observed with carbon and oxygen K-edge X-ray absorption spectroscopy

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-2881-2021 ◽

2021 ◽

Vol 21 (4) ◽

pp. 2881-2894

Author(s):

Georgia Michailoudi ◽

Jack J. Lin ◽

Hayato Yuzawa ◽

Masanari Nagasaka ◽

Marko Huttula ◽

...

Keyword(s):

Aqueous Solutions ◽

Absorption Spectroscopy ◽

Atmospheric Chemistry ◽

Aldol Condensation ◽

Cloud Formation ◽

Aqueous Environment ◽

Aerosol Formation ◽

X Ray ◽

Dilute Aqueous Solutions ◽

X Ray Absorption

Abstract. Glyoxal (CHOCHO) and methylglyoxal (CH3C(O)CHO) are well-known components of atmospheric particles and their properties can impact atmospheric chemistry and cloud formation. To get information on their hydration states in aqueous solutions and how they are affected by the addition of inorganic salts (sodium chloride (NaCl) and sodium sulfate (Na2SO4)), we applied carbon and oxygen K-edge X-ray absorption spectroscopy (XAS) in transmission mode. The recorded C K-edge spectra show that glyoxal is completely hydrated in the dilute aqueous solutions, in line with previous studies. For methylglyoxal, supported by quantum chemical calculations we identified not only C–H, C=O and C–OH bonds, but also fingerprints of C–OH(CH2) and C=C bonds. The relatively low intensity of C=O transitions implies that the monohydrated form of methylglyoxal is not favored in the solutions. Instead, the spectral intensity is stronger in regions where products of aldol condensation and enol tautomers of the monohydrates contribute. The addition of salts was found to introduce only very minor changes to absorption energies and relative intensities of the observed absorption features, indicating that XAS in the near-edge region is not very sensitive to these intermolecular organic–inorganic interactions at the studied concentrations. The identified structures of glyoxal and methylglyoxal in an aqueous environment support the uptake of these compounds to the aerosol phase in the presence of water and their contribution to secondary organic aerosol formation.

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Aqueous phase behavior of glyoxal and methylglyoxal observed with carbon and oxygen K-edge X-ray absorption spectroscopy

10.5194/acp-2020-393 ◽

2020 ◽

Author(s):

Georgia Michailoudi ◽

Jack J. Lin ◽

Hayato Yuzawa ◽

Masanari Nagasaka ◽

Marko Huttula ◽

...

Keyword(s):

Aqueous Solutions ◽

Absorption Spectroscopy ◽

Atmospheric Chemistry ◽

Aldol Condensation ◽

Cloud Formation ◽

Aqueous Environment ◽

Aerosol Formation ◽

X Ray ◽

Dilute Aqueous Solutions ◽

X Ray Absorption

Abstract. Glyoxal (CHOCHO) and methylglyoxal (CH3C(O)CHO) are well-known components of atmospheric particles and their properties can impact atmospheric chemistry and cloud formation. To get information on their hydration states in aqueous solutions and how they are affected by addition of inorganic salts (sodium chloride (NaCl) and sodium sulfate (Na2SO4)), we applied carbon and oxygen K-edge X-ray absorption spectroscopy (XAS) in transmission mode. The recorded C K-edge spectra show that glyoxal is completely hydrated in the dilute aqueous solutions, in line with previous studies. For methylglyoxal, we identified, supported by quantum chemical calculations, not only C-H, C=O and C-OH bonds, but also fingerprints of C-OH(CH2) and C=C bonds. This implies the presence of both mono- and dihydrated forms of methylglyoxal, as well as products of aldol condensation, and enol tautomers of the monohydrates. The addition of salts was found to introduce only very minor changes to absorption energies and relative intensities of the observed absorption features, indicating that the organic-inorganic interactions at the studied concentrations are not strong enough to affect the spectra in this work. The identified structures of glyoxal and methylglyoxal in aqueous environment support the uptake of these compounds to the aerosol phase in the presence of water and their contribution on secondary organic aerosol formation.

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New pathways of the reaction of OH radicals with dimethyl sulfide based on CH3SCH2O2 isomerization

10.5194/egusphere-egu2020-10345 ◽

2020 ◽

Author(s):

Torsten Berndt ◽

Wiebke Scholz ◽

Bernhard Mentler ◽

Lukas Fischer ◽

Erik Hans Hoffmann ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Dimethyl Sulfide ◽

Peroxy Radical ◽

Product Formation ◽

Experimental Investigations ◽

Oh Radicals ◽

Atmospheric Conditions ◽

Free Jet ◽

Isomerization Process ◽

Efficient Detection

Dimethyl sulfide (DMS), produced by marine organisms, represents the most abundant, biogenic sulfur emission into the Earth&#180;s atmosphere. The gas-phase degradation of DMS is mainly initiated by the reaction with the OH radical forming first CH3SCH2O2 radicals from the dominant H-abstraction channel. A fast CH3SCH2O2 isomerization process was proposed as a result of quantum chemical calculations. In the present study, experimental investigations on the product formation from OH + DMS have been conducted in a free-jet flow system at 295&#160;&#177;&#160;2&#160;K and 1 bar air. Very efficient detection of CH3SCH2O2 isomerization products has been achieved by iodide-CI-APi-TOF measurements allowing to run the reaction for close to atmospheric conditions. It is experimentally shown that the CH3SCH2O2 radicals undergo a two-step isomerization process finally forming a product consistent with the formula HOOCH2SCHO. The isomerization process is accompanied by OH recycling. The rate-limiting first isomerization step, CH3SCH2O2 &#8594; CH2SCH2OOH proceeds with k = (0.23 &#177; 0.12) s-1 at 295&#160;&#177;&#160;2&#160;K. Competing bimolecular CH3SCH2O2 reactions with NO, HO2 or RO2 radicals are less important for trace-gas conditions over the oceans. &#160;Results of atmospheric chemistry simulations demonstrate the predominance (&#8805;95%) of CH3SCH2O2 isomerization. The rapid peroxy radical isomerization, not yet considered in models, substantially changes the understanding of DMS&#180;s degradation processes in the atmosphere.

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Secondary organic aerosol formation from biomass burning emissions

10.5194/acp-2019-326 ◽

2019 ◽

Cited By ~ 2

Author(s):

Christopher Y. Lim ◽

David H. Hagan ◽

Matthew M. Coggon ◽

Abigail R. Koss ◽

Kanako Sekimoto ◽

...

Keyword(s):

Biomass Burning ◽

Secondary Organic Aerosol ◽

Total Concentration ◽

Organic Aerosol ◽

Oh Radicals ◽

Aerosol Formation ◽

Atmospheric Aging ◽

Aerosol Mass ◽

Photochemical Aging ◽

Organic Gases

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes is not fully understood. As part of the Fire Influence on Regional and Global Environments Experiment (FIREX 2016), we investigated the effect of photochemical aging on biomass burning organic aerosol (BBOA), with a focus on fuels from the western United States. Emissions were sampled into a small (150 L) environmental chamber and photochemically aged via the addition of ozone and irradiation by 254 nm light. While some fraction of species undergoes photolysis, the vast majority of aging occurs via reaction with OH radicals, with total OH exposures corresponding to the equivalent of up to 10 days of atmospheric oxidation. For all fuels burned, large and rapid changes are seen in the ensemble chemical composition of BBOA, as measured by an aerosol mass spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for all aging experiments and continues to grow with increasing OH exposure, but the magnitude of the SOA formation is highly variable between experiments. This variability can be explained well by a combination of experiment-to-experiment differences in OH exposure and the total concentration of non-methane organic gases (NMOGs) in the chamber before oxidation, measured by PTR-ToF-MS (r2 values from 0.64 to 0.83). From this relationship, we calculate the fraction of carbon from biomass burning NMOGs that is converted to SOA as a function of equivalent atmospheric aging time, with carbon yields ranging from 24 ± 4 % after 6 hours to 56 ± 9 % after 4 days.

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Atmospheric Chemistry of CH3CH2OCH3: Kinetics and Mechanism of Reactions with Cl Atoms and OH Radicals

International Journal of Chemical Kinetics ◽

10.1002/kin.21051 ◽

2016 ◽

Vol 49 (1) ◽

pp. 10-20 ◽

Cited By ~ 5

Author(s):

Mads P. Sulbaek Andersen ◽

Sissel Bjørn Svendsen ◽

Freja From Østerstrøm ◽

Ole John Nielsen

Keyword(s):

Atmospheric Chemistry ◽

Kinetics And Mechanism ◽

Oh Radicals ◽

Cl Atoms

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Oceanic phytoplankton are a potentially important source of benzenoids to the remote marine atmosphere

Communications Earth & Environment ◽

10.1038/s43247-021-00253-0 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Manon Rocco ◽

Erin Dunne ◽

Maija Peltola ◽

Neill Barr ◽

Jonathan Williams ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Dimethyl Sulfide ◽

Laboratory Culture ◽

Marine Phytoplankton ◽

Marine Atmosphere ◽

Aerosol Formation ◽

Incubation Experiments ◽

Phytoplankton Communities ◽

Anthropogenic Air Pollutants ◽

Benzene Toluene

AbstractBenzene, toluene, ethylbenzene and xylenes can contribute to hydroxyl reactivity and secondary aerosol formation in the atmosphere. These aromatic hydrocarbons are typically classified as anthropogenic air pollutants, but there is growing evidence of biogenic sources, such as emissions from plants and phytoplankton. Here we use a series of shipborne measurements of the remote marine atmosphere, seawater mesocosm incubation experiments and phytoplankton laboratory cultures to investigate potential marine biogenic sources of these compounds in the oceanic atmosphere. Laboratory culture experiments confirmed marine phytoplankton are a source of benzene, toluene, ethylbenzene, xylenes and in mesocosm experiments their sea-air fluxes varied between seawater samples containing differing phytoplankton communities. These fluxes were of a similar magnitude or greater than the fluxes of dimethyl sulfide, which is considered to be the key reactive organic species in the marine atmosphere. Benzene, toluene, ethylbenzene, xylenes fluxes were observed to increase under elevated headspace ozone concentration in the mesocosm incubation experiments, indicating that phytoplankton produce these compounds in response to oxidative stress. Our findings suggest that biogenic sources of these gases may be sufficiently strong to influence atmospheric chemistry in some remote ocean regions.

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Atmospheric chemistry of trans-CF3CHCHCl: Kinetics of the gas-phase reactions with Cl atoms, OH radicals, and O3

Journal of Photochemistry and Photobiology A Chemistry ◽

10.1016/j.jphotochem.2008.05.013 ◽

2008 ◽

Vol 199 (1) ◽

pp. 92-97 ◽

Cited By ~ 35

Author(s):

M.P. Sulbaek Andersen ◽

E.J.K. Nilsson ◽

O.J. Nielsen ◽

M.S. Johnson ◽

M.D. Hurley ◽

...

Keyword(s):

Gas Phase ◽

Atmospheric Chemistry ◽

Oh Radicals ◽

Gas Phase Reactions ◽

Kinetics Of ◽

Cl Atoms

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Air Temperature and Anthropogenic Forcing: Insights from the Solid Earth

Journal of Climate ◽

10.1175/2010jcli3500.1 ◽

2011 ◽

Vol 24 (2) ◽

pp. 569-574 ◽

Cited By ~ 13

Author(s):

Jean O. Dickey ◽

Steven L. Marcus ◽

Olivier de Viron

Keyword(s):

Air Temperature ◽

Decadal Variability ◽

Surface Air Temperature ◽

Radiation Budget ◽

Cloud Formation ◽

Length Of Day ◽

Anthropogenic Forcing ◽

The Core ◽

Earth’S Radiation Budget ◽

Gas Effect

Abstract Earth’s rotation rate [i.e., length of day (LOD)], the angular momentum of the core (CAM), and surface air temperature (SAT) all have decadal variability. Previous investigators have found that the LOD fluctuations are largely attributed to core–mantle interactions and that the SAT is strongly anticorrelated with the decadal LOD. It is shown here that 1) the correlation among these three quantities exists until 1930, at which time anthropogenic forcing becomes highly significant; 2) correcting for anthropogenic effects, the correlation is present for the full span with a broadband variability centered at 78 yr; and 3) this result underscores the reality of anthropogenic temperature change, its size, and its temporal growth. The cause of this common variability needs to be further investigated and studied. Since temperature cannot affect the CAM or LOD to a sufficient extent, the results favor either a direct effect of Earth’s core-generated magnetic field (e.g., through the modulation of charged-particle fluxes, which may impact cloud formation) or a more indirect effect of some other core process on the climate—or yet another process that affects both. In all three cases, their signals would be much smaller than the anthropogenic greenhouse gas effect on Earth’s radiation budget during the coming century.

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