Influence of water‐soluble organic carbon on cloud drop number concentration

Ervens, B.

doi:10.1029/2004jd005634

Cited by 150 publications

(188 citation statements)

References 41 publications

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“…In Figure 4, the very high end for the measured GF r , n water /n solute and mfs versus water activity plots are shown for (NH 4 ) 2 SO 4 and are compared with simulations from the E-AIM model (solid lines). In this case, the highest a w reached with this averaged data set is 0.997, corresponding to a GF r value of 6.22 ( Figure 4A).…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

“…At molalities higher than 1 mol kg −1 , the close agreement between the measured and modeled osmotic coefficients for all systems suggests that the Figure 4. GF r , n water /n solute , and mfs for a w values between 0.88 and 1 for (NH 4 ) 2 SO 4 . Symbols: filled circles, experimental data points averaged over a minimum of 10 droplets; solid lines, calculated curves from the E-AIM model.…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

“…Sensitivity to Small Changes in Chemical Composition. Hygroscopic growth measurements on mixtures of NaCl and (NH 4 ) 2 SO 4 were also taken to evaluate the sensitivity of the experimental method to small changes in the chemical composition of the aerosol droplets. Three different (NH 4 ) 2 SO 4 /NaCl mass ratios were considered (50/50, 90/10, and 95/5) and the mfs and GF r vs a w experimental curves (circles) are compared with simulations from the E-AIM model (dashed lines) in Figure 8.…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

“…For the calculation of growth factors of these mixtures, the reference dry state is considered to be a solid particle made of nonmixed crystalline ammonium sulfate and sodium chloride. The dry density is calculated estimating the dry volumes separately for NaCl and (NH 4 ) 2 SO 4 and calculating the ratio between the total mass and the total volume of the two dry salts.…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

“…As an example, cloud parcel models have shown that the cloud droplet number can vary by as much as 50% depending on the strength of the assumed hygroscopic growth as saturation is approached. 4 Rigorous thermodynamic models for calculating the hygroscopic response of mixed component aerosol have been developed on the basis of bulk phase and aerosol phase measurements of the equilibrium response of binary solutions of a single solute and water. 5,6 When combined with treatments of solution density and surface tension, accurate predictions of the variation in equilibrium particle size with relative humidity are possible.…”

Section: Introductionmentioning

confidence: 99%

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Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity

et al. 2016

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Using a comparative evaporation kinetics approach, we describe a new and accurate method for determining the equilibrium hygroscopic growth of aerosol droplets. The time-evolving size of an aqueous droplet, as it evaporates to a steady size and composition that is in equilibrium with the gas phase relative humidity, is used to determine the time-dependent mass flux of water, yielding information on the vapor pressure of water above the droplet surface at every instant in time. Accurate characterization of the gas phase relative humidity is provided from a control measurement of the evaporation profile of a droplet of know equilibrium properties, either a pure water droplet or a sodium chloride droplet. In combination, and by comparison with simulations that account for both the heat and mass transport governing the droplet evaporation kinetics, these measurements allow accurate retrieval of the equilibrium properties of the solution droplet (i.e., the variations with water activity in the mass fraction of solute, diameter growth factor, osmotic coefficient or number of water molecules per solute molecule). Hygroscopicity measurements can be made over a wide range in water activity (from >0.99 to, in principle, <0.05) on time scales of <10 s for droplets containing involatile or volatile solutes. The approach is benchmarked for binary and ternary inorganic solution aerosols with typical uncertainties in water activity of <±0.2% at water activities >0.9 and ∼±1% below 80% RH, and maximum uncertainties in diameter growth factor of ±0.7%. For all of the inorganic systems examined, the time-dependent data are consistent with large values of the mass accommodation (or evaporation) coefficient (>0.1).

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Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity

et al. 2016

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Key parameters controlling OH‐initiated formation of secondary organic aerosol in the aqueous phase (aqSOA)

et al. 2014

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Secondary organic aerosol formation in the aqueous phase of cloud droplets and aerosol particles (aqSOA) might contribute substantially to the total SOA burden and help to explain discrepancies between observed and predicted SOA properties. In order to implement aqSOA formation in models, key processes controlling formation within the multiphase system have to be identified. We explore parameters affecting phase transfer and OH(aq)-initiated aqSOA formation as a function of OH(aq) availability. Box model results suggest OH(aq)-limited photochemical aqSOA formation in cloud water even if aqueous OH(aq) sources are present. This limitation manifests itself as an apparent surface dependence of aqSOA formation. We estimate chemical OH(aq) production fluxes, necessary to establish thermodynamic equilibrium between the phases (based on Henry's law constants) for both cloud and aqueous particles. Estimates show that no (currently known) OH(aq) source in cloud water can remove this limitation, whereas in aerosol water, it might be feasible. Ambient organic mass (oxalate) measurements in stratocumulus clouds as a function of cloud drop surface area and liquid water content exhibit trends similar to model results. These findings support the use of parameterizations of cloud-aqSOA using effective droplet radius rather than liquid water volume or drop surface area. Sensitivity studies suggest that future laboratory studies should explore aqSOA yields in multiphase systems as a function of these parameters and at atmospherically relevant OH(aq) levels. Since aerosol-aqSOA formation significantly depends on OH(aq) availability, parameterizations might be less straightforward, and oxidant (OH) sources within aerosol water emerge as one of the major uncertainties in aerosol-aqSOA formation.

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CCN activity of secondary aerosols from terpene ozonolysis under atmospheric relevant conditions

Cheng

Diao

et al. 2017

JGR Atmospheres

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Gas‐phase ozonolysis of terpenes is an important source of atmospheric secondary organic aerosol. The contribution of terpene‐derived aerosols to the atmospheric cloud condensation nucleus (CCN) burden under atmospheric conditions, however, remains highly uncertain. The results obtained in previous studies under simple laboratory conditions may not be applicable to atmospheric relevant conditions. Here we present that CCN activities of aerosols from terpene ozonolysis can be significantly affected by atmospheric relevant species that can act as stabilized Criegee intermediate (SCI) or OH scavengers. Ozonolysis reactions of α‐pinene, limonene, α‐cedrene, and α‐humulene were conducted in a 4.5 m3 collapsible fluoropolymer chamber at near‐atmospheric concentrations in the presence of different OH scavengers (cyclohexane, 2‐butanol, or CO) and SCI scavengers (CH3COOH, H2O, or SO2). The number size distribution and CCN activity of aerosol particles formed during ozonolysis were simultaneously determined. Additionally, particulate products were chemically analyzed by using a Filter Inlet for Gases and AEROsols High‐Resolution Time‐of‐Flight Chemical‐Ionization Mass Spectrometer. Results showed that aerosol CCN activity following monoterpene ozonolysis was more sensitive to the choice of OH scavengers, while that from sesquiterpene ozonolysis was significantly affected by SCI scavengers. Combined with chemical analysis results, it was concluded that the unimolecular decomposition of CIs giving hygroscopic organic products can be largely suppressed by bimolecular reactions during sesquiterpene ozonolysis but was not significantly impacted in monoterpene ozonolysis. Our study underscores the key role of CIs in the CCN activity of terpene ozonolysis‐derived aerosols. The effects of atmospheric relevant species (e.g., SO2, H2O, and CO) need to be considered when assessing the contribution of biogenic terpenes to the atmospheric CCN burden under ambient conditions.

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Influence of water‐soluble organic carbon on cloud drop number concentration

Cited by 150 publications

References 41 publications

Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity

Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity

Key parameters controlling OH‐initiated formation of secondary organic aerosol in the aqueous phase (aqSOA)

CCN activity of secondary aerosols from terpene ozonolysis under atmospheric relevant conditions

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