Surfactant effect on cloud condensation nuclei for two‐component internally mixed aerosols

Petters, Sarah Suda; Petters, M. D.

doi:10.1002/2015jd024090

Cited by 101 publications

(158 citation statements)

References 151 publications

(250 reference statements)

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“…This is consistent with a slight dynamic shape factor of 1.01-1.04 of crystallized ammonium sulfate (Biskos et al 2006;Zelenyuk et al 2006). Somewhat larger deviations were seen for sodium chloride, which has a dynamic shape factor of »1.08 in its cubic crystalline form (Zelenyuk et al 2006;Wang et al 2010;Petters and Petters 2016). More strongly shaped crystalline particles may bias viscosity estimates if D c and D uc are not both known.…”

Section: ¡3supporting

confidence: 69%

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Rothfuss

Petters

2016

Aerosol Science and Technology

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Viscosity of atmospheric aerosol spans at least 15 orders of magnitude, from thin liquids to glassy solids, with possible concomitant impact on multiple processes of meteorological and/or climatological concern. Recently there has been interest in aerosol phase assessment techniques based upon dimer coalescence. Theoretical treatment suggests discernible reductions in dimer diameter begin when viscosity »10 8 Pa¢s and the dimer is spherical at »10 5 Pa¢s for submicron particles, or the middle range of the semisolid regime. A method using nanoparticle dimers synthesized by utilizing differential mobility analyzers of opposite polarity to produce monomers of opposite charge that subsequently undergo electrostatically mediated coagulation has been developed and is detailed in this work. This method was used to assess the aerosol phase state of several atmospherically relevant organic species and inorganic salts at relative humidity (RH) values ranging between 10% and 100%. Ammonium sulfate, monosodium a-ketoglutaric acid, sodium chloride, and sucrose all displayed RH-dependent phase state. These observed viscous transitions occurred at RH values less than existing deliquescence RH data, a result consistent with existing literature reports of RH-induced structural rearrangements. Fully coalesced and fully uncoalesced diameters could be fitted to single values, indicating that the presented technique is absolute. The method was also used to assess the phase state of dry sucrose aerosol at temperatures between 20 C and 70 C. A phase transition was noted at 63.7 C § 4.4 C, near the glass transition temperature, suggesting the presented method may also be useful for probing phase responses to temperature perturbations.

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Section: ¡3supporting

confidence: 69%

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Rothfuss

Petters

2016

Aerosol Science and Technology

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“…Aerosols were generated by atomizing the aqueous solutions. Previous work has suggested that incomplete mixing of aerosol components in aqueous solution and/or fractionation of components during atomization can contribute to variability and uncertainty in hygroscopicity measurements for aerosol systems containing surface-active components, particularly for components with low water solubility (Petters and Petters, 2016). However, because PEG is highly water soluble, it is not expected that this was a significant contributor to uncertainty in experimental results.…”

Section: Aerosol Systemsmentioning

confidence: 99%

Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

et al. 2016

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Abstract. Discontinuities in apparent hygroscopicity below and above water saturation have been observed for organic and mixed organic-inorganic aerosol particles in both laboratory studies and in the ambient atmosphere. However, uncertainty remains regarding the factors that contribute to observations of low hygroscopic growth below water saturation but enhanced cloud condensation nuclei (CCN) activity for a given aerosol population. Utilizing laboratory surrogates for oligomers in atmospheric aerosols, we explore the extent to which such discontinuities are influenced by organic component molecular mass and viscosity, non-ideal thermodynamic interactions between aerosol components, and the combination of these factors. Measurements of hygroscopic growth under subsaturated conditions and the CCN activity of aerosols comprised of polyethylene glycol (PEG) with average molecular masses ranging from 200 to 10 000 g mol −1 and mixtures of PEG with ammonium sulfate (AS) were conducted. Experimental results are compared to calculations of hygroscopic growth at thermodynamic equilibrium conducted with the Aerosol Inorganic Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model, and the potential influence of kinetic limitations on observed water uptake was further explored through estimations of water diffusivity in the PEG oligomers. Particle-phase behavior, including the prevalence of liquid-liquid phase separation (LLPS), was also modeled with AIOMFAC. Under subsaturated relative humidity (RH) conditions, we observed little variability in hygroscopic growth across PEG systems with different molecular masses; however, an increase in CCN activity with increasing PEG molecular mass was observed. This effect is most pronounced for PEG-AS mixtures, and, in fact, an enhancement in CCN activity was observed for the PEG10000-AS mixture as compared to pure AS, as evidenced by a 15 % reduction in critical activation diameter at a supersaturation of 0.8 %. We also observed a marked increase in apparent hygroscopicity for mixtures of higher molecular mass PEG and AS under supersaturated conditions as compared to subsaturated hygroscopic growth. AIOMFAC-based predictions and estimations of water diffusivity in PEG suggest that such discontinuities in apparent hygroscopicity above and below water saturation can be attributed, at least in part, to differences in the sensitivity of water uptake behavior to surface tension effects. There is no evidence that kinetic limitations to water uptake due to the presence of viscous aerosol components influenced hygroscopic growth. For the systems that display an enhancement in apparent hygroscopicity above water saturation, LLPS is predicted to persist to high RH. This indicates a miscibilityPublished by Copernicus Publications on behalf of the European Geosciences Union. 12768 N. Hodas et al.: Discontinuities in the hygroscopicity of oligomers gap and is likely to influence bulk-to-surface partitioning of PEG at high RH, impacting droplet surface tension and CCN activity....

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“…No observable change in the particle flow temperature or humidity was measured after valve switching actions. Glucose was chosen as a reference compound because it is non-volatile at the time scale of DMA transit, its water activity vs. water content relationship is precisely known from isopiestic measurements (Miyajima et al 1983), the water activity vs. water content relationship is essentially independent of temperature (Zamora et al 2011;Christensen and Petters 2012), the variation of glucose growth factors with S H2O is similar to that of GLY allowing measurements to stay within a narrower overall DMA sizing range, and the dried dynamic particle shape factor approaches unity (Suda and Petters 2013;Petters and Petters 2016). The resulting humidigrams reflect the combined hygroscopic growth and evaporation at a fixed temperature vs. S H 2 O .…”

Section: Experimental Scan Strategiesmentioning

confidence: 99%

Thermodynamic and kinetic behavior of glycerol aerosol

Wright

Song

Sears

et al. 2016

Aerosol Science and Technology

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Glycerol and propylene glycol mixtures are common carrier solutions in electronic cigarettes. Aerosols produced from these mixtures will evaporate quickly in a dry environment due to their high volatility. In a humid environment, such as the lungs, the kinetics of evaporation and hygroscopic growth determine the evolution of aerosol plume glycerol. Here, we apply a temperature and relative humidity-controlled hygroscopicity/volatility tandem differential mobility analyzer system to study the growth and evaporation kinetics of glycerol aerosol over a wide range of temperature, relative humidity, and residence times. Results show that at dry conditions glycerol aerosols evaporate within seconds at temperatures warmer than 20 C and that the accommodation coefficient of glycerol vapor on dry glycerol particles is 0.8. Under humidified conditions, the mutual depression of vapor pressures of the aqueous glycerol/water solution slows the glycerol evaporation rate consistent with thermodynamic and kinetic model predictions. Model calculations show that water vapor aided condensation of glycerol can occur at high relative humidity for glycerol vapor concentrations that result in glycerol particle evaporation under dry conditions. The combined results will help with constraining computational modules that model the evolution of glycerol-containing aerosols along a prescribed thermodynamic trajectory.

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Surfactant effect on cloud condensation nuclei for two‐component internally mixed aerosols

Cited by 101 publications

References 151 publications

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

Thermodynamic and kinetic behavior of glycerol aerosol

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