Investigation of molar volume and surfactant characteristics of water-soluble organic compounds in biomass burning aerosol
نویسندگان
چکیده
In this study, we characterize the CCN activity of the water-soluble organics in biomass burning aerosol. The aerosol after collection upon filters is dissolved in water using sonication. Hydrophobic and hydrophilic components are fractionated from a portion of the original sample using solid phase extraction, and subsequently desalted. The surface tension and CCN activity of these different samples are measured with a KSV CAM 200 goniometer and a DMT Streamwise Thermal Gradient CCN Counter, respectively. The measurements show that the strongest surfactants are isolated in the hydrophobic fraction, while the hydrophilics exhibit negligible surface tension depression. The presence of salts (primarily (NH4)2SO4) in the hydrophobic fraction substantially enhances surface tension depression; their synergistic effects considerably enhance CCN activity, exceeding that of pure (NH4)2SO4. From our analysis, average thermodynamic properties (i.e, molar volume) are determined for samples using our newly developed Köhler Theory Analysis (KTA) method. The molar mass of the hydrophilic and hydrophobic aerosol components is estimated to be 87±26 g mol−1 and 780±231 g mol−1, respectively. KTA also suggests that the relative proportion (in moles) of hydrophobic to hydrophilic compounds in the original sample to be 1:3. For the first time, KTA is applied to an aerosol with this level of complexity and displays its potential for providing physically-based constraints for GCM parameterizations of the aerosol indirect effect.
منابع مشابه
Interactive comment on “Investigation of molar volume and surfactant characteristics of water-soluble organic compounds in biomass burning aerosol” by A. Asa-Awuku et al
متن کامل
Köhler Theory Analysis for biomass burning aerosol
Investigation of molar volume and surfactant characteristics of water-soluble organic compounds in biomass burning aerosol A. Asa-Awuku, A. Nenes, A. P. Sullivan, C. J. Hennigan, and R. J. Weber School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA now at: Dep...
متن کاملChemical characterization of the ambient organic aerosol soluble in water: 2. Isolation of acid, neutral, and basic fractions by modified size- exclusion chromatography
[1] A method employing size-exclusion chromatography (SEC) with Total Organic Carbon detection is developed to isolate and quantify the water-soluble organic carbon (WSOC) component of ambient aerosol particles by acid, neutral, and basic functional groups. The method provides unique quantitative insights into the characteristics and possible sources of a large fraction of the organic aerosol. ...
متن کاملLow molecular weight organic acids in aerosol particles from Rondônia, Brazil, during the biomass-burning, transition and wet periods
Particles from biomass burning and regional haze were sampled in Rondônia, Brazil, during dry, transition and wet periods from September to November 2002, as part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate) field campaign. Water soluble organic and inorganic compounds in bulk (High Volume and Stacked Filter Unit sam...
متن کاملFunctional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley
The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component....
متن کامل