| Title: | Evidence for liquid-like and nonideal behavior of a mixture of organic aerosol components |
| Author(s): | Cappa CD; Lovejoy ER; Ravishankara AR; |
| Address: | "Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA. cdcappa@ucdavis.edu" |
| ISSN/ISBN: | 1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking) |
| Abstract: | "The condensation, evaporation, and repartitioning of semivolatile organic compounds (SVOCs) in the atmosphere depends both on the phase of condensed material and the effective condensed phase vapor pressures of the SVOCs. Although direct measurements of vapor pressures of individual SVOCs exist, there are limited measurements of how the properties of a given compound changes in mixtures of multiple components that exist in the atmosphere. Here, the evaporation behavior of mixtures of dicarboxylic acids, which are common atmospheric aerosol constituents, is investigated. These measurements demonstrate that complex mixtures of the individually solid organic compounds take on liquid-like properties. Additionally, the vapor pressures of individual components show strong, identity-dependent deviations from ideality (i.e., Raoult's Law), with the vapor pressures of the smaller, more volatile compounds decreased significantly in the mixtures. The addition of an inorganic compound (NaNO(3)) further influences the nonideal behavior, again in a compound-specific manner. These results suggest that nonideal behavior of particle-phase compounds influences the abundances of organic aerosol observed in the atmosphere and in the laboratory" |
| Keywords: | Aerosols/*chemistry Atmosphere Humans Organic Chemicals/*chemistry Particle Size Phase Transition Volatilization; |
| Notes: | "MedlineCappa, Christopher D Lovejoy, Edward R Ravishankara, A R eng Research Support, U.S. Gov't, Non-P.H.S. 2008/11/21 Proc Natl Acad Sci U S A. 2008 Dec 2; 105(48):18687-91. doi: 10.1073/pnas.0802144105. Epub 2008 Nov 19" |
