Influence of Organic Films on the Hygroscopicity of Ultrafine Sulfuric Acid Aerosol

Xiong, Judy Q.; Zhong, Mianhua; Fang, C. P.; Chen, Lung Chi; Lippmann, Morton

doi:10.1021/es980019q

Cited by 93 publications

(82 citation statements)

References 25 publications

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“…In general, our results with the rather little soluble O 3 are in line with previous studies. Xiong et al (1998) showed that a C 18 coating reduced the hydroscopic growth rate of sulphuric acid aerosol, while a coating of oleic acid (nonlinear and unsaturated) had no effect, likely related to the fact that oleic acid does not form condensed liquid films at pressures, where the saturated straight chain C 18 fatty acid does (Seidl, 2000). Similarly, related the permeability of monolayers to the molecular properties and pressure-area isotherms and demonstrated that the uptake of acetic acid through monolayers of saturated C 18 and C 30 alcohols into an aqueous phase was strongly reduced.…”

Section: Discussionmentioning

confidence: 99%

The effect of fatty acid surfactants on the uptake of ozone to aqueous halogenide particles

Rouvière

Ammann

2010

Atmos. Chem. Phys.

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Abstract. The reactive uptake of ozone to deliquesced potassium iodide aerosol particles coated with linear saturated fatty acids (C 9 , C 12 , C 15 , C 18 and C 20 ) was studied. The experiments were performed in an aerosol flow tube at 293 K and atmospheric pressure. The uptake coefficient on pure deliquesced KI aerosol was γ = (1.10±0.20)×10 −2 at 72-75% relative humidity. In presence of organic coatings, the uptake coefficient decreased significantly for long straight chain surfactants (≥C 15 ), while it was only slightly reduced for the short ones (C 9 , C 12 ). We linked the kinetic results to the monolayer properties of the surfactants, and specifically to the expected phase state of the monolayer formed (liquid expanded or liquid condensed state). The results showed a decrease of the uptake coefficient by 30% for C 12 , 85% for C 15 and 50% for C 18 in presence of a monolayer of a fatty acid at the equilibrium spreading pressure at the air/water interface. The variation among C 12 , C 15 and C 18 follows the density of the monolayer at equilibrium spreading pressure, which is highest for the C 15 fatty acid. We also investigated the effect of organic films to mixed deliquesced aerosol composed of a variable mixture of KI and NaCl, which allowed determining the resistance exerted to O 3 at the aqueous surface by the two longer chained surfactants pentadecanoic acid (C 15 ) and stearic acid (C 18 ). For these, the probability that a molecule hitting the surface is actually transferred to the aqueous phase underneath was β C 15 = 6.8 × 10 −4 and β C 18 = 3.3 × 10 −4 , respectively. Finally, the effect of twocomponent coatings, consisting of a mixture of long and short chained surfactants, was studied qualitatively.

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Section: Discussionmentioning

confidence: 99%

The effect of fatty acid surfactants on the uptake of ozone to aqueous halogenide particles

Rouvière

Ammann

2010

Atmos. Chem. Phys.

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“…Sjogren et al (2004) found that (NH 4 ) 2 SO 4 -adipic acid particles (50 wt% and 76wt% adipic acid) exhibited a lower G f at a residence time of less than 4 s than the G f at more than 4 s at 78-91%RH after deliquescence. Xiong et al (1998) found that submicrometer sulfuric acid (H 2 SO 4 ) particles attained their equilibrium size within 6 s. On the other hand, the G f of H 2 SO 4 particles coated with three monolayers of lauric acid further increased as the residence time increased from 6 s to 10 s, providing evidence that the coated H 2 SO 4 particles had not yet reached their equilibrium size within 6 s. Organic films can act a physical barrier to retard the water condensation (or evaporation) rate in planar solutions and on particle surfaces (Gill et al, 1983;Barnes, 1986) and can lower the accommodation coefficient (Pandis et al, 1995). A summary of laboratory studies on the evaporation and condensation rates of water vapor from particles in the presence of organic films has been presented by Chuang (2003).…”

Section: Laboratory Measurementsmentioning

confidence: 99%

“…McMurry and Stolzenburg (1989) pointed out that the effects of organic coatings or surfactants in atmospheric particles on the equilibrium time are unknown. It is possible that an organic coating or surface-active compounds can hinder the transport of water across the particle/air interface and result in non-equilibrium growth measurements in field studies using a TDMA (Xiong et al, 1998).…”

Section: Field Measurementsmentioning

confidence: 99%

Mass transfer effects in hygroscopic measurements of aerosol particles

Chan

2005

Atmos. Chem. Phys.

100

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Abstract.The tandem differential mobility analyzer (TDMA) has been widely utilized to measure the hygroscopicity of laboratory-generated and atmospheric submicrometer particles. An important concern in investigating the hygroscopicity of the particles is if the particles have attained equilibrium state in the measurements. We present a literature survey to investigate the mass transfer effects in hygroscopicity measurements. In most TDMA studies, a residence time in the order of seconds is used for humidification (or dehumidification). NaCl and (NH 4 ) 2 SO 4 particles are usually used to verify the equilibrium measurements during this residence time, which is presumed to be sufficient for other particles. There have been observations that not all types of submicrometer particles, including atmospheric particles, attain their equilibrium sizes within this time scale. We recommend that experimentation with different residence times be conducted and that the residence time should be explicitly stated in future TDMA measurements. Mass transfer effects may also exist in the measurements of other properties related to the water uptake of atmospheric particles such as relative humidity dependent light scattering coefficients and cloud condensation nuclei activity.

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“…This does not necessarily rule out similarities: salt particles in Helsinki might be coated with, e.g. hydrocarbons from traffic and other combustion processes that affect their water solubility (Hansson et al, 1998;Xiong et al, 1998). Another potential explanation is that the higher growth mode in Helsinki results from ageing: originally less-hygroscopic particles tend to gain soluble properties when aged (e.g.…”

Section: Frequency Of Occurrencementioning

confidence: 99%

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles

et al. 2002

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Abstract. An Ultrafine Tandem Differential Mobility Analyser (UF-TDMA) has been used in several field campaigns over the last few years. The investigations were focused on the origin and properties of nucleation event aerosols, which are observed frequently in various environments. This paper gives a summary of the results of 10 nm and 20 nm particle hygroscopic properties from different measurement sites: an urban site, an urban background site and a forest site in Finland and a coastal site in western Ireland. The data can be classified in four hygroscopic growth classes: hydrofobic, less-hygroscopic, more-hygroscopic and sea-salt. Similar classification has been earlier presented for Aitken and accumulation mode particles. In urban air, the summertime 10 nm particles showed varying less-hygroscopic growth behaviour, while winter time 10 nm and 20 nm particles were externally mixed with two different hygroscopic growth modes. The forest measurements revealed diurnal behaviour of hygroscopic growth, with high growth factors at day time and lower during night. The urban background particles had growth behaviour similar to the urban and forest measurement sites depending on the origin of the observed particles. The coastal measurements were strongly affected by air mass history. Both 10 nm and 20 nm particles were hygroscopic in marine background air. The 10 nm particles produced during clean nucleation burst periods were hydrofobic. Diurnal variation and higher growth factors of 10 nm particles were observed in air affected by other source regions. External mixing was occasionally observed at all the sites, but incidents with more than two growth modes were Correspondence to: K. Hämeri (kaarle.hameri@occuphealth.fi) extremely rare.

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Influence of Organic Films on the Hygroscopicity of Ultrafine Sulfuric Acid Aerosol

Cited by 93 publications

References 25 publications

The effect of fatty acid surfactants on the uptake of ozone to aqueous halogenide particles

The effect of fatty acid surfactants on the uptake of ozone to aqueous halogenide particles

Mass transfer effects in hygroscopic measurements of aerosol particles

Field measurements of hygroscopic properties and state of mixing of nucleation mode particles

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