Rate of atmospheric brown carbon whitening governed by environmental conditions

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(38)

Published: Sept. 12, 2022

Biomass burning organic aerosol (BBOA) in the atmosphere contains many compounds that absorb solar radiation, called brown carbon (BrC). While BBOA is atmosphere, BrC can undergo reactions with oxidants such as ozone which decrease absorbance, or whiten. The effect of temperature and relative humidity (RH) on whitening has not been well constrained, leading to uncertainties when predicting direct radiative climate. Using an flow-tube reactor, we show by oxidation strongly dependent RH temperature. a poke-flow technique, viscosity also depends these conditions. measured rate described data, assuming due occurring bulk BBOA, within thin shell beneath surface. our combined datasets, developed kinetic model this process, lifetime 1 d less below ∼1 km altitude but often much longer than above altitude. Including dependence chemical transport causes large change predicted warming Overall, results illustrate need be considered understand role atmosphere.

Language: Английский

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Viscosity, Glass Formation, and Mixing Times within Secondary Organic Aerosol from Biomass Burning Phenolics

ACS Earth and Space Chemistry, Journal Year: 2023, Volume and Issue: 7(7), P. 1388 - 1400

Published: June 13, 2023

Biomass burning events emit large amounts of phenolic compounds, which are oxidized in the atmosphere and form secondary organic aerosol (SOA). Using poke-flow technique, we measured relative humidity (RH)-dependent viscosities SOA generated by oxidation three biomass compounds: catechol, guaiacol, syringol. All systems had viscosity < 3 × 103 Pa s at RH ≳ 40% > 2 108 ≲ 3% room temperature. At values 0–10%, these were least orders magnitude higher than primary from burning. We also developed a parameterization for predicting as function Based on this parameterization, is strongly dependent both Under dry conditions, highly viscous temperature (∼109 s) becomes glass (viscosity 1012 when 280 K. For tropospheric values, often liquid state (η 102 below ∼2 km altitude, semi-solid (102 η between ∼9 km, glassy above km. Furthermore, mixing time molecules 200 nm particle exceeds 1 h troposphere.

Language: Английский

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Molecular Insights into Gas–Particle Partitioning and Viscosity of Atmospheric Brown Carbon

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 4, 2024

Biomass burning organic aerosol (BBOA), containing brown carbon chromophores, plays a critical role in atmospheric chemistry and climate forcing. However, the effects of evaporation on BBOA volatility viscosity under different environmental conditions remain poorly understood. This study focuses molecular characterization laboratory-generated proxies from wood pyrolysis emissions. The initial mixture, "pyrolysis oil (PO

Language: Английский

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Secondary Organic Aerosol from Biomass Burning Phenolic Compounds and Nitrate Radicals can be Highly Viscous over a Wide Relative Humidity Range

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(49), P. 21702 - 21715

Published: Nov. 27, 2024

Biomass burning events, including wildfires, can emit large amounts of phenolic compounds such as guaiacol. These undergo oxidation by nitrate radicals (NO

Language: Английский

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Insect Infestation Increases Viscosity of Biogenic Secondary Organic Aerosol

ACS Earth and Space Chemistry, Journal Year: 2023, Volume and Issue: 7(5), P. 1060 - 1071

Published: April 25, 2023

Plant stress alters emissions of volatile organic compounds. However, little is known about how this could influence climate-relevant properties secondary aerosol (SOA), particularly from complex mixtures such as real plant emissions. In study, the chemical composition and viscosity were examined for SOA generated healthy aphid-stressed Canary Island pine (Pinus canariensis) trees, which are commonly used landscaping in Southern California. Healthy (HCIP) stressed (SCIP) aerosols a 5 m3 environmental chamber at 35–84% relative humidity room temperature via OH-initiated oxidation. Viscosities collected particles measured using an offline poke-flow method, after conditioning humidified air flow. SCIP consistently more viscous than HCIP particles. The largest differences particle observed conditioned 50% where was order magnitude larger that increased tree attributed to fraction sesquiterpenes emission profile. particles, both aphid-stressed, α-pinene demonstrating limitation single monoterpene model compound predict physicochemical biogenic SOA. synthetic composed only few major compounds present (<10 compounds) can reproduce viscosities

Language: Английский

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Secondary Organic Aerosol from Biomass Burning Phenolics Could Increase Brown Carbon Lifetimes, Seed Ice Clouds, and Transport Pollutants

Published: Jan. 31, 2023

Biomass burning events emit large amounts of phenolic compounds, which are oxidized in the atmosphere and form secondary organic aerosol (SOA). Using poke-flow technique, we measured room-temperature relative humidity (RH)-dependent viscosities SOA generated by oxidation three biomass compounds: catechol, guaiacol, syringol. All systems had viscosity < 3 × 10³ Pa s at RH ⪆ 40% > 2 10⁸ ⪅ 3%. At values 0-10%, these were least orders magnitude higher than primary (POA) from burning. These results suggest that mixing POA may extend lifetime brown carbon atmosphere. Based on an extrapolation our to tropospheric temperature values, is a glassy state (𝜂 10¹² s) above ∼6 km troposphere, potentially acting as heterogeneous ice nuclei clouds, thereby influencing climate. Furthermore, time molecules 200 nm particle exceeds 1 h has implications for long-range transport pollutants.

Language: Английский

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Effects of volatility, viscosity, and non-ideality on particle–particle mixing timescales of secondary organic aerosols

Aerosol Science and Technology, Journal Year: 2023, Volume and Issue: 58(4), P. 411 - 426

Published: Sept. 26, 2023

Different populations of aerosol are constantly mixed throughout the atmosphere. Large-scale models often assume no particle–particle mixing or fast among populations, so that they stay externally instantaneously form internal mixtures. We apply kinetic multilayer model gas–particle interactions (KM-GAP) to simulate evaporation semi-volatile species from one particle population and partitioning into another with various phase states nonideal conditions. find timescale (τmix) is prolonged when transport a in which it miscible, as more mass must be transported. Extremes volatility prolong τmix, low-volatility evaporate slowly, while high-volatility condense slowly. When bulk diffusivities two greater than 10−15 cm2 s−1, mix rapidly; otherwise, τmix can beyond 1 h. KM-GAP experiments H-toluene SOA D-toluene limonene SOA, showing toluene highly viscous, initial gas rapid because low viscosity SOA. Simulations β-caryophyllene indicate apparent discrepancy limited under conditions where both predicted have explained by miscibility components. Our study demonstrates timescales affected complex interplay volatility, diffusion limitations, non-ideal miscibility.

Language: Английский

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Estimating viscosity of individual substrate-deposited particles from measurements of their height-to-width ratios

Aerosol Science and Technology, Journal Year: 2023, Volume and Issue: 58(4), P. 401 - 410

Published: Oct. 16, 2023

AbstractAirborne particles alter the radiative forcing of climate and have further consequences on air visibility, atmospheric chemistry, human health. Recent studies reported existence highly viscous semisolid even solid amorphous organic aerosol (OA) particles. Particle viscosity has an impact heterogeneous gas-particle partitioning, ice nucleation properties. Consequently, variations in particle must be considered when predicting OA. Here, we use scanning electron microscopy (SEM) transmission X-ray (STXM) to estimate individual deposited substrates based their characteristic height-to-width ratios, which are affected by changes morphology upon deposition. The ratios obtained from SEM STXM exhibit a strong correlation, demonstrating that both imaging approaches can applied separately for assessment substrate-deposited While these metrics largely qualitative, this method enables rapid ranges, distinguishing between (>1010 Pa·s), (104–108 liquid (10°–101 Pa·s) within ensembles ambient collected studies.Copyright © 2023 American Association Aerosol ResearchEditor: Cari Dutcher AcknowledgmentsThe project was performed at Life Science Microscope Facility Purdue University. beamline 5.3.2.2 Advanced Light Source Lawrence Berkeley National Laboratory. We thank Mr. Mark Carlsen, instrumentation specialist Purdue's Jonathan Amy Chemical Instrumentation, assembling drying system used generation collection.Authors' contributionsF.R. A.L. devised project. F.R., J.T., M.F., R.M. conducted measurements. F. R. E.M. laboratory experiments, samples standards, measurements, analyzed integrated all datasets. M.L. provided geometry derivations. F.R. wrote manuscript with contributions coauthors. authors report there no competing interests declare.Disclosure statementNo potential conflict interest author(s).Additional informationFundingU. S. Department Energy, Office Biological Environmental Research, Atmospheric System Research program, award DE-SC0021977.

Language: Английский

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Viscosity of aqueous ammonium nitrate–organic particles: Equilibrium partitioning may be a reasonable assumption for most tropospheric conditions

Published: May 30, 2024

Abstract. The viscosity of aerosol particles determines the critical mixing time gas–particle partitioning volatile compounds in atmosphere. semi-volatile ammonium nitrate (NH4NO3) might alter highly viscous secondary organic during their lifetime. In contrast to particles, data on internally mixed inorganic–organic are scarce. We determined an aqueous ternary system consisting NH4NO3 and a proxy compound for organic, sucrose. Three techniques were applied cover atmospherically relevant humidity range: viscometry, fluorescence recovery after photobleaching, poke-flow technique. show that viscosities NH4NO3–sucrose–H2O with inorganic dry mass ratio 4:1 four orders magnitude lower than those sucrose under low conditions (30 % relative (RH), 293 K). By comparing predictions rules AIOMFAC-VISC model, we found rule based mole fractions performs similarly when from corresponding binary subsystems available. Applying this rule, estimated characteristic internal indicating significantly faster inorganic—organic mixtures compared electrolyte-free especially at RH’s. Hence, assumption global atmospheric chemistry models quasi-instantaneous equilibrium is reasonable single-phase containing dissolved electrolytes (but not necessarily phase-separated particles), most planetary boundary layer. This may even hold entire troposphere mid-latitudes RH > 35 %.

Language: Английский

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Viscosity of aqueous ammonium nitrate–organic particles: equilibrium partitioning may be a reasonable assumption for most tropospheric conditions

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(23), P. 13341 - 13359

Published: Dec. 3, 2024

Abstract. The viscosity of aerosol particles determines the critical mixing time gas–particle partitioning volatile compounds in atmosphere. semi-volatile ammonium nitrate (NH4NO3) might alter highly viscous secondary organic during their lifetimes. In contrast to particles, data on internally mixed inorganic–organic are scarce. We determined an aqueous ternary system consisting NH4NO3 and a proxy compound for organic, sucrose. Three techniques were applied cover atmospherically relevant humidity range: viscometry, fluorescence recovery after photobleaching, poke-flow technique. show that NH4NO3–sucrose–H2O with inorganic dry mass ratio 4:1 is 4 orders magnitude lower than sucrose under low-humidity conditions (30 % relative (RH), 293 K). By comparing predictions rules those Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients Viscosity (AIOMFAC-VISC) model, we found rule based mole fractions performs similarly when from corresponding binary subsystems available. Applying this rule, estimated characteristic internal indicating significantly faster mixtures compared electrolyte-free especially at RH. Hence, assumption global atmospheric chemistry models quasi-instantaneous equilibrium reasonable single-phase containing dissolved electrolytes (but not necessarily phase-separated particles), most planetary boundary layer. Further needed see whether holds entire troposphere midlatitudes RH > 35 %.

Language: Английский

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