Laboratory studies of the influence of thin organic films on the neutralization reaction of H2SO4 aerosol with ammonia

Däumer, B; Nießner, Reinhard; Klockow, D.

doi:10.1016/0021-8502(92)90001-c

Cited by 65 publications

(86 citation statements)

References 30 publications

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“…Jefferson et al (1997) Seinfeld (2002), 0.65 and Easter et al (2004), 0.02. Laboratory and field studies have shown that the value of a e is reduced as a particle becomes increasingly covered in surfactants (Däumer et al, 1992). Marine air contains substantial surfactant concentrations from ocean bubble bursting which may be able to coat marine aerosol particles, thereby reducing accommodation coefficients.…”

Section: Balance Of Nucleation and Condensationmentioning

confidence: 99%

A global off-line model of size-resolved aerosol microphysics: II. Identification of key uncertainties

et al. 2005

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Abstract. We use the new GLOMAP model of global aerosol microphysics to investigate the sensitivity of modelled sulfate and sea salt aerosol properties to uncertainties in the driving microphysical processes and compare these uncertainties with those associated with aerosol and precursor gas emissions. Overall, we conclude that uncertainties in microphysical processes have a larger effect on global sulfate and sea salt derived condensation nuclei (CN) and cloud condensation nuclei (CCN) concentrations than uncertainties in present-day sulfur emissions. Our simulations suggest that uncertainties in predicted sulfate and sea salt CCN abundances due to poorly constrained microphysical processes are likely to be of a similar magnitude to long-term changes in sulfate and sea salt CCN due to changes in anthropogenic emissions. A microphysical treatment of the global sulfate aerosol allows the uncertainty in climate-relevant aerosol properties to be attributed to specific processes in a way that has not been possible with simpler aerosol schemes. In particular we conclude that: (1) changes in the binary H 2 SO 4 -H 2 O nucleation rate and condensation rate of gaseous H 2 SO 4 cause a shift in the vertical location of the upper tropospheric CN layer by as much as 3 km, while the shape of the CN profile is essentially pre-served (2) uncertainties in the binary H 2 SO 4 -H 2 O nucleation rate have a relatively insignificant effect on marine boundary layer (MBL) aerosol properties; (3) emitting a fraction of anthropogenic SO 2 as particulates (to represent production of sulfate particles in power plant plumes below the scale of the model grid (which is of the order of 300 km)) has the potential to change the global mean MBL sulfate-derived CN concentrations by up to 72%, and changes of up to a factor 20 can occur in polluted continental regions; (4) predicted global mean MBL sulfate and sea salt CCN concentrations change by 10 to 60% when several microphysical processes are changed within reasonable uncerCorrespondence to: D. V. Spracklen (dominick@env.leeds.ac.uk) tainty ranges; (5) sulfate and sea salt derived CCN concentrations are particularly sensitive to primary particle emissions, with global mean MBL sulfate and sea salt CCN changing by up to 27% and local concentrations over continental regions changing by more than 100% when the percentage of anthropogenic SO 2 emitted as particulates is changed from 0 to 5%; (6) large changes in sea spray flux have insignificant effects on global sulfate aerosol except when the mass accommodation coefficient of sulfuric acid on the salt particles is set unrealistically low.

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Section: Balance Of Nucleation and Condensationmentioning

confidence: 99%

A global off-line model of size-resolved aerosol microphysics: II. Identification of key uncertainties

et al. 2005

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“…Studies have shown that the presence of a surface active organic on ammonium sulfate and ammonium nitrate aerosols will decrease water evaporation rates (Shulman et al, 1997;. Further a coating of surface active organics can act as a barrier for the reactivity and transport of trace atmospheric gases into the bulk aerosol (Niessner, 1984;Daumer et al, 1992;Folkers et al, 2003). However, the effect of the coatings on water uptake and phase changes is not clear.…”

Section: Introductionmentioning

confidence: 99%

Impact of palmitic acid coating on the water uptake and loss of ammonium sulfate particles

et al. 2005

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Abstract. While water insoluble organics are prevalent in the atmosphere, it is not clear how the presence of such species alters the chemical and physical properties of atmospheric aerosols. Here we use a combination of FTIR spectroscopy, Transmission Electron Microscopy (TEM) and Aerosol Mass Spectrometry (AMS) to characterize ammonium sulfate particles coated with palmitic acid. Coated aerosols were generated by atomizing pure ammonium sulfate, mixing the particles with a heated flow of nitrogen with palmitic acid vapor, and then flowing the mixture through an in-line oven to create internally mixed particles. The mixing state of the particles was probed using the AMS data and images from the TEM. Both of these probes suggest that the particles were internally mixed. Water uptake by the mixed particles was then probed at 273 K. It was found that for ammonium sulfate containing ∼20 wt% palmitic acid the deliquescence relative humidity (DRH) was the same as for pure ammonium sulfate (80±3% RH). For particles with ∼50 wt% palmitic acid however, the mixed particles began to take up water at relative humidities as low at 69% and continued to slowly take up water to 85% RH without fully deliquescing. In addition to studies of water uptake, water loss was also investigated. Here coatings of up to 50 wt% had no impact on the efflorescence relative humidity. These studies suggest that even if insoluble substances coat salt particles in the atmosphere, there may be relatively little effect on the resulting water uptake and loss.

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“…Similarly, Xiong et al (1998) observed that a C18 coating reduced the hydroscopic growth rate of sulphuric acid aerosol, while coatings of oleic acid had no effect, even though they also saw an inhibition by the C12 acid, which should not have been in a condensed monolayer state. The uptake of gaseous ammonia to sulphuric acid droplets was shown to be strongly hindered by coatings of hexadecane or hexadecanol (Däumer et al, 1992). A monolayer of these compounds was found to reduce the uptake • C according to the model of Seidl (2000).…”

Section: Discussion Of Effects Of Fatty Acid Coatingsmentioning

confidence: 97%

“…A number of recent studies have addressed the effects of organic coatings on the phase transfer of atmospherically relevant molecules (Däumer et al, 1992;Jefferson et al, 1997;Folkers et al, 2003;Thornton and Abbatt, 2005;Glass et al, 2006;Gilman and Vaida, 2006;McNeill et al, 2006;Park et al, 2007;Clifford et al, 2007;Cosman et al, 2008). The observed effects different surfactants have vary substantially and depend on the substrate, the monolayer properties and also on the type of trace gas and its sink process in the condensed phase.…”

Section: Introductionmentioning

confidence: 99%

The effect of fatty acid surfactants on the uptake of nitric acid to deliquesced NaCl aerosol

et al. 2008

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Abstract. Surface active organic compounds have been observed in marine boundary layer aerosol. Here, we investigate the effect such surfactants have on the uptake of nitric acid (HNO 3 ), an important removal reaction of nitrogen oxides in the marine boundary layer. The uptake of gaseous HNO 3 on deliquesced NaCl aerosol was measured in a flow reactor using HNO 3 labelled with the short-lived radioactive isotope 13 N. The uptake coefficient γ on pure deliquesced NaCl aerosol was γ =0.5±0.2 at 60% relative humidity and 30 ppb HNO 3 (g). The uptake coefficient was reduced by a factor of 5-50 when the aerosol was coated with saturated linear fatty acids with carbon chain lengths of 18 and 15 atoms in monolayer quantities. In contrast, neither shorter saturated linear fatty acids with 12 and 9 carbon atoms, nor coatings with the unsaturated oleic acid (C18, cisdouble bond) had a detectable effect on the rate of HNO 3 uptake. It is concluded that it is the structure of the monolayers formed, which determines their resistance towards HNO 3 uptake. Fatty acids (C18 and C15), which form a highly ordered film in the so-called liquid condensed state, represent a significant barrier towards HNO 3 uptake, while monolayers of shorter-chain fatty acids (C9, C12) and of the unsaturated oleic acid form a less ordered film in the liquid expanded state and do not hinder the uptake. Similarly, high contents of humic acids in the aerosol, a structurally inhomogeneous, quite water soluble mixture of oxidised high molecular weight organic compounds did not affect HNO 3 uptake. As surfactant films on naturally occurring aerosol Correspondence to: M. Ammann (markus.ammann@psi.ch) are expected to be less structured due to their chemical inhomogeneity, it is likely that their inhibitory effect on HNO 3 uptake is smaller than that observed here for the C15 and C18 fatty acid monolayers.

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Laboratory studies of the influence of thin organic films on the neutralization reaction of H2SO4 aerosol with ammonia

Cited by 65 publications

References 30 publications

A global off-line model of size-resolved aerosol microphysics: II. Identification of key uncertainties

A global off-line model of size-resolved aerosol microphysics: II. Identification of key uncertainties

Impact of palmitic acid coating on the water uptake and loss of ammonium sulfate particles

The effect of fatty acid surfactants on the uptake of nitric acid to deliquesced NaCl aerosol

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