title: Size dependence of the structure of organic aerosol.
abstract: The effects of aerosol particles on heterogeneous atmospheric chemistry and climate are determined in part by the internal arrangement of compounds within the particles. We have used cryo-transmission electron microscopy to investigate the phase separation behavior of model organic aerosol composed of ammonium sulfate internally mixed with succinic or pimelic acid. We have found that no particle with a diameter <170 nm for succinic acid and 270 nm for pimelic acid is phase separated. Larger particles adopt a phase separated, partially engulfed structure. We therefore demonstrate that phase separation of aerosol particles is dependent on particle size and discuss implications for aerosol-climate interactions.
authors.affiliation: Department of Chemistry, The Pennsylvania State University , 104 Chemistry Building, University Park, Pennsylvania 16802, United States.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Veghte
authors.forename: Muhammad Bilal
authors.initials: MB
authors.lastname: Altaf
authors.forename: Miriam Arak
authors.initials: MA
authors.lastname: Freedman